References 13 website: JMR, http://fluoroquinolonethyroid.com

References 13

Links, Abstracts, Articles, etc.

These links should work as of 2014; sometimes you have to click on them

several times; if they don’t work, then Google/search the titles

Many of these are tryptophan-related topics; additional include: Myasthenia

Gravis, Nopterin, FQ’s, serotonin, choline, carnitine

Includes interesting discussion on MDMA overdose “Serotonin Syndrome”

http://www.ncbi.nlm.nih.gov/pubmed/7852347 Mutation of a conserved amino acid residue

(tryptophan 1173) in the tyrosine kinase domain of the IGF-I receptor abolishes autophosphorylation

but does not eliminate biologic function.

https://books.google.com/books?id=Vw9_Q5ut4UMC&pg=PA324&lpg=PA324&dq=tyrosine+kinase+tryp

tophan&source=bl&ots=m-PDFIhglm&sig=-

hxUMEvgGr3BYdcpVEILJO_hi2M&hl=en&sa=X&ved=0CFIQ6AEwCWoVChMI79vLh-

z_xwIVBAqSCh1KfgJ_#v=onepage&q=tyrosine%20kinase%20tryptophan&f=false Bioinformatics for

Geneticists: A Bioinformatics Primer for the Analysis of . . . “Tryptophan can be replaced by other

aromatic residues, but it is unique in chemistry and size, meaning often that replacement by anything

could be disastrous.”

From book “Recent Advances in Tryptophan Research: Tryptophan and Serotonin Pathways”: “ . . .the

biological significance of IDO induction . . . when tissues are invaded by viruses, bacteria, or parasites,

leukocytes and lymphocytes will accumulate at the site and interferon will be produced by these cells in

the inflammatory loci. The interferon thus produced is released and interacts with cell surface to trigger

IDO induction in the same or other type of cells. As a consequence of inflammation, superoxide anion is

liberated and serves as a substrate for IDO. Although it is possible that some tryptophan metabolites

may activate the immune system or act as bacteriostatic agents, available evidence does not support

this hypothesis. We therefore tentatively conclude that tryptophan is degraded by IDO and depleted,

whereby the growth of viruses, bacteria, and certain parasites is inhibited, because tryptophan is the

least available and therefore most important essential amino acid for their growth.

References 13 website: JMR, http://fluoroquinolonethyroid.com

Note: from Wiki: Indoleamine-pyrrole 2,3-dioxygenase (IDO or INDO EC 1.13.11.52) is an enzyme that

in humans is encoded by the IDO1 gene.[1][2] This enzyme catalyzes the degradation of the essential

amino acid L-tryptophan to N-formylkynurenine.[3] Indoleamine 2,3-dioxygenase is the first and rate-

limiting enzyme of tryptophan catabolism through kynurenine pathway, thus causing depletion of

tryptophan which can cause halted growth of microbes as well as T cells. IDO is an immune checkpoint

molecule in the sense that it is an immunomodulatory enzyme produced by some alternatively activated

macrophages and other immunoregulatory cells (also used as an immune subversion strategy by many

tumors). Interferon-gamma has an antiproliferative effect on many tumor cells and inhibits intracellular

pathogens such as Toxoplasma and chlamydia, at least partly because of the induction of indoleamine

2,3-dioxygenase. It has been shown that IDO permits tumor cells to escape the immune system by

depletion of L-Trp in the microenvironment of cells. A wide range of human cancers such as prostatic,

colorectal, pancreatic, cervical, gastric, ovarian, head, lung, etc. overexpress human IDO (hIDO).[4][5]

From the book: Tryptophan: Biochemical and Health Implications: “ . . . the actions of L-tryptophan on

hepatic cells may be similar to those of a hormone, such as insulin, steroid hormones, or T3 . . . a

competition may exist between hydrocortisone and tryptophan for receptor proteins on rat liver cytosol

. . . the maximal biological activity of one compound may be impaired by the other [Trp and

Dexamethasone] . . . the biologic effects of T3, estrogen, and retinoic acid indicate that their cognate

receptors can act to regulate distinct but overlapping sets of genes. Recent findings suggest a probable

relationship between nuclear receptors for T3 and tryptophan. Both ligands, T3 and tryptophan, affect

the binding affinity of the nuclear receptor for tryptophan . . . T3 may inhibit tryptophan transport to the

liver. A mutual competitive inhibition between the transport of tryptophan (mediated by the aromatic

amino acid transport system T) and T3 has been reported . . . interactions between thyroid hormone and

tryptophan transport in rat liver have been reported to be modulated by thyroid status . . .L-tryptophan

in blood binds to serum albumin (85% bound, 15% free).

From Wiki https://en.wikipedia.org/wiki/Hypertryptophanemia One of these kynurenines, aptly named

kynurenic acid, serves as a neuroprotectant through its function as an antagonist at both nicotinic and

glutamate receptors (responsive to the neurotransmitters nicotine and glutamate, respectively).[11][12]

This action is in opposition to the , another kynurenine, noted for its potential as a neurotoxin.[10][13]

Quinolinic acid activity has been associated with neurodegenerative disorders such as Huntington's

disease, the neuroprective abilities of kynurenic acid forming a counterbalance against this process, and

the related excitotoxicity and similar damaging effects on neurons

https://en.wikipedia.org/wiki/Kynurenine_pathway Dysfunctional states of distinct steps of the

kynurenine pathway (e.g. kynurenine, kynurenic acid, quinolinic acid, anthranilic acid, 3 -

Hydroxykynurenine) have been described for a number of disorders, e.g.:[25] HIV dementia, Tourette

Syndrome, Tic disorders, Psychiatric disorders (e.g. Schizophrenia, major depression, anxiety disorders),

Multiple sclerosis, Huntington's disease, Encephalopathies, Lipid metabolism, Liver fat metabolism,

Systemic lupus erythematosus, Glutaric aciduria, Vitamin B6 deficiency, Eosinophilia-myalgia syndrome

https://en.wikipedia.org/wiki/Quinolinic_acid IDO-1, IDO-2 and TDO are present in microglia and

macrophages. Under inflammatory conditions and conditions of T cell activation, leukocytes are retained

References 13 website: JMR, http://fluoroquinolonethyroid.com

in the brain by cytokine and chemokine production, which can lead to the breakdown of the BBB, thus

increasing the quinolinic acid that enters the brain. Furthermore, quinolinic acid has been shown to play

a role in destabilization of the cytoskeleton within astrocytes and brain endothelial cells, contributing to

the degradation of the BBB, which results in higher concentrations of quinolinic acid in the brain . . . In

normal cell conditions, astrocytes in the neuron will provide a glutamate-glutamine cycle, which results

in reuptake of glutamate from the synapse into the pre-synaptic cell to be recycled, keeping glutamate

from accumulating to lethal levels inside the synapse. At high concentrations, quinolinic acid inhibits

glutamine synthetase, a critical enzyme in the glutamate-glutamine cycle. In addition, It can also

promote glutamate release and block its reuptake by astrocytes. All three of these actions result in

increased levels of glutamate activity that could be neurotoxic.[10] This results in a loss of function of

the cycle, and results in an accumulation of glutamate. This glutamate further stimulates the NMDA

receptors, thus acting synergistically with quinolinic acid to increase its neurotoxic effect by increasing

the levels of glutamate, as well as inhibiting its uptake. In this way, quinolinic acid self-potentiates its

own toxicity.[10] Furthermore, quinolinic acid results in changes of the biochemistry and structure of

the astrocytes themselves, resulting in an apoptotic response. A loss of astrocytes results in a pro-

inflammatory effect, further increasing the initial inflammatory response which initiates quinolinic acid

production

http://www.clinchem.org/content/43/12/2424.full Simultaneous Measurement of Serum Tryptophan

and Kynurenine by HPLC

http://www.neurology.org/content/42/1/43.short Neuroactive kynurenines in Lyme borreliasis

http://www.ncbi.nlm.nih.gov/pubmed/25420916 Induction of indoleamine 2,3-dioxygenase by Borrelia

burgdorferi in human immune cells correlates with pathogenic potential.

Interesting discussion on serotonin syndrome here, guy talking about MDMA overdose aftermath:

http://www.bluelight.org/vb/threads/607040-Serotonin-Syndrome-aftermath

I got your message. From your initial description, it doesn't sound like 'severe' serotonin syndrome - although I will

admit that ANY serotonin syndrome can feel VERY severe to the person going through it. Tachycardia is the first

symptom in most cases and the chest pain can be so severe it resembles a heart-attack. Since you didn't mention

an immediate fear of death....I am going to assume the chest pain was moderate. Mine scared the SHIT out of me.

I literally thought my heart stopped then started again, racing faster than sprinting a mile could cause! In addition

to initial tachycardia, 'severe' SS normally involves STRONG stomach and intestinal cramps. For me the pain began

just below my stomach and the swelling was externally visible. I literally thought my liver was going to EXPLODE. I

WISH I had gotten diarrhea - instead my intestines filled with fluid yet remained paralyzed. To this day, they seem

to be recovering muscle tone and rhythm. Then there is the greatest sign of all - FEVER. Anything above 101.4 is

considered serious. At 104 brain cells begin dying, and serotonin toxicity is greatly potentiated. At 108 most

References 13 website: JMR, http://fluoroquinolonethyroid.com

humans expire no matter what. A mild fever, say 99 degrees F, is still a sign of SS. But we are talking a matter of

degree. If your tachycardia was not absolutely shocking and your body temp didn't go over 100 degrees... And

you managed to shit your guts out... You are probably going to be MUCH better off than myself. The fact that you

got to the hospital might have prevented more serious complications such as hyponatremia, stroke, renal and liver

toxicity... That is good news for you, but the question remains - what have you done to your brain? I would begin

by asking you how you FEEL? The first few days after MDMA toxicity, whether it is SS or not, are very surreal.

Many people describe feeling disconnected from their bodies at least at some point. They feel dizzy, disoriented,

and FULL of anxiety. The tone of your thread seems to lack this anxiety factor. The panic is so strong in the

people I have met that they plead with the BL community for help and visit multiple doctors in a short period of

time. How is your vision? How is your appetite? Are you sleeping? For myself and many others, lack of sleep is

the most OBVIOUS symptom. The first week after my SS, my head was ringing like a tuning fork! Sleep

disturbances are seen in research and have been shown to be a universal symptom of MDMA toxicity in humans.

Loss of sleep also worsens cognitive ability and increases anxiety substantially. I was able to feel an appetite, but

eating produced EXTREME suffering and anxiety for the entire first month or recovery. And this became obvious

the very first day! BL and Erowid contain many examples of people drastically altering their diet. We are talking

about fast-food eating stoners going VEGAN. Quite a change. And then there is the anxiety and obsession. They

will spend HOURS searching the internet for an answer about what kind of 'brain damage' has occurred to them.

And they will be shocked and disappointed at doctors who know nothing about serotonin! Where do you fit into

this equation? How do you FEEL? SS can cause severe and crippling anxiety, changes in vision, appetite, sleep,

and the ability to socialize. As the serotonin network is rewired, the brain maintains a high level of the stress

hormone cortisol. Prolactin may also be elevated, which can be linked to anhedonia - including the ability to

experience ANY pleasure during orgasm. Or feel libido in the first place... Along with these hormonal symptoms,

dopamine imbalance may also occur. The higher brain is deprived of it, and the limbic system receives an

abundance! This type of imbalance is seen in psychotic disorders like schizophrenia. Serotonin inhibits dopamine

and damage to the network causes improper serotonin transmission, and therefore dopamine suppression.

Dopamine imbalance, combined with elevated cortisol and prolactin... It is a horrific combination - a soul

destroying recipe. Ironically, this same combination of events occurs during MDMA use! Just to a lesser degree

and in the right sequence. Recovery from MDMA can feel strangely like MDMA does - but only the worst parts.

Drugs you cannot use: Anything that agonizes or releases serotonin. All psychedelics are out - mushrooms, LSD,

MDMA, RCs, etc. Tramadol, DXM, high dose benedryl... You need to be checking ALL drugs for serotonin activity

prior to taking. Of course, tryptophan and 5-HTP are OUT. So is weed. Smoking cannabis causes serotonin activity

in the brain - NOT what you want. Some of the worst panic attacks and episodes of

depersonalization/derealization occurred after smoking just a few hits of weed. It took me over six months to be

able to smoke, and even then it was TWO HITS max. Since I had no tolerance it was plenty... And even at 14

months now I have lost interest in the stuff. When my recovery is fully complete, I may revisit pot - but not like I

ever smoked before.

Long-term use of cannabis is associated with increased psychological problems among MDMA users. While the

extent of MDMA use predicts the cognitive deficit, it is the extent of cannabis use that predicts the psychological

deficit. This could be due to the fact that cannabis alters the shape and size of the prefrontal cortex, the highest

brain region and the ultimate dopamine target of MDMA. Loss of serotonin in this region is a long-term feature of

MDMA toxicity. Eventually some recovery of serotonin DOES occur, even in the distant PFC. But it is the last

region to recover in the network. That is the good news from research - there is hope for all. Even among heavy,

long-term users 'clinical' recovery occurs between 12-18 months. In some cases it goes to 2 years, but this is

unusual. Clinical recovery is defined as a cessation of anxiety and depression and a restoration of normal activity.

References 13 website: JMR, http://fluoroquinolonethyroid.com

There are still lingering cognitive alterations....and changes in endocrine function. Some BL members concede

that the effects can linger for many years....but most will state that around the ONE year mark, things improved

significantly. I agree with that statement - between months 11-13 I noticed a big improvement in sleep. And the

ability to walk away from research and posting for days/weeks in a row.

Drugs you can take: Alcohol in limited amounts. It kills nerve growth factors in the brain, but it acts upon the

GABA receptors which are safe for you. Continued or heavy drinking will only halt your recovery, so I recommend

strict limitations - like 3 beers, 4 tops. Benzos also act upon GABA and are quite safe. They are administered

during acute MDMA reactions to shut down toxic glutamate activity. Note - continued use of benzos will result in

higher levels of glutamate! More than a few days use is enough to cause aggression in most people. And long-

term use causes people to feel like they are having heart-attacks when they stop taking it. There is only one more

option for you - opiates. In higher doses, many of them have modest effects on serotonin. So I recommend taking

very small doses, but hydrocodone and oxy seem to be acceptable options. Again, moderation is the key... Your

dopamine system might not respond much to them, and heavy or continued use is only going to make you feel

much worse. Tramadol is not an opiate, it is an opioid with strong serotonin and noradrenaline releasing

properties. Stay away from that one! Those are the three drugs you can use now alcohol, benzos, and opiates.

Ketamine is a possibility, but MICRO doses are the only recommendation I will offer. Higher doses do have a

marked anti-depressant effect, but they also cause schizophrenic symptoms and dissociation from the body. The

're-emergence phenomena' is not pleasant at all. But some BL members claim that regular low dose IM ketamine

regrows brain cells...

Your best bet is to EXERCISE. I guarantee this will make you feel better. You have to do it. Exercise releases a

serotonin growth factor, BDNF. It resprouts axons and increases the plasticity of existing ones! Twenty minutes

per day, five days in a row. I PROMISE results. It is time to start taking care of yourself - eating right, sleeping

right, exercise, sunlight, socializing. And the harder these things are to do, the MORE important they are to your

brain function. If you have to FORCE it, good. It will benefit you in ways you cannot imagine. I'm done for now,

be sure to let me know if you have any other questions. You know where to find me. FBC

http://www.quora.com/Why-are-the-amino-acids-tryptophan-and-tyrosine-found-at-the-lipid-

membrane-border-in-membrane-proteins Why are the amino acids tryptophan and tyrosine found at

the lipid membrane border in membrane proteins? Giridhar Sekar, PhD. in Biochemistry.

http://www.chem.tamu.edu/rgroup/hilty/index.php?pg=group2 (Contact Giridhar Sekar). https://en.wikipedia.org/wiki/Membrane_protein

Giridhar Sekar I am still learning. Follow185

Giridhar has 30+ answers and 5 endorsements in

Biochemistry The study of chemical processes that occur naturally in living organisms. Follow41.5k

Biochemistry.

References 13 website: JMR, http://fluoroquinolonethyroid.com

There are 2 main types of membrane proteins, namely α-helical bundles and β-barrel proteins. In both kinds of proteins, aromatic amino acids localize on the interface between the solvent and the biological membrane. Specifically, among the 4 aromatic amino acids, 3 of them (viz. Histidine, Tyrosine, Tryptophan) are known to localize in the lipid/water interface. On the other hand, Phenylalanine is typically considered to be distributed throughout the transmembrane layer [1]. Additionally, tryptophan is more commonly found in the non-cytoplasmic side of the protein. These localized aromatic residues form what are called "aromatic belts" in a membrane protein. Edit : Figure included from [1] showing distibution of aminoacids along the lipid bilayer.

Here is a figure showing Tyr and Trp residues in the β-barrel membrane protein OmpX. Please forgive the fact that the lines indicating the bilayer were drawn by hand roughly. I assure you that they are within reasonable error. You may look up reference [2], if you need a more accurate picture.

The prevalent understanding is that these residues help the anchoring of membrane proteins to the biological membranes by interaction with the head group of lipids. In membrane proteins these residues have been demonstrated to orient themselves to face the lipid head groups when they are a part of the aromatic belt [3]. Tryptophan residues have been shown to cause localized perturbation of the membrane such as increasing the membrane thickness etc. [4] Additionally, the orientation of the sidechains of these residues also seem to be a determinant factor in the interactions that these residues have with the lipid [5]. Additionally when speculating the role of these aromatic belts, one can also consider this major difference between helical bundles and barrel proteins. It has been observed that in helical bundles the aromatic belts are located 30 Å apart, which is roughly the thickness of a generic biological membrane. In barrel proteins the belts are usually located much closer to each other (20 Å) [1]. This leads to speculation whether these proteins mediate a local "squeezing" of the membrane in barrel proteins by virtue of interactions of aromatic residues with lipid head groups. But such arguments have to be taken with a pinch of salt because these β-barrel proteins are found exclusively in bacterial outer

References 13 website: JMR, http://fluoroquinolonethyroid.com

membranes of Gram-negative bacteria and in organelle membranes of the chloroplast and mitochondria in eukaryotes (I will understand if you will want to take a time-out and reflect on the relevance of this observation towards the Symbiogenesis theory.). These membranes are different because they are asymmetric. For example, the inner leaf of the Bacterial outer membrane is composed of phospholipids, while the outer leaf contains lipopolysaccharides as well. References [1] M.B. Ulmschneider and M.S.P. Sansom. Biochimica et Biophysica Acta 1512 (2001) 1-14. Link [2] Mahalakshmi et al. Biochimica et Biophysica Acta. 2007 Dec; 1768(12):3216-24. Epub 2007 Aug 24. Link [3] Pilpel et al. Journal of Molecular Biology, Volume 294, Issue 4, 10 December 1999, Pages 921–935. Link [4] de Planque et al. Journal of Biological Chemistry, Vol. 274, No. 30, Issue of July 23, pp. 20839–20846, 1999. Link [5] Tieleman et al. Biochemistry 1998, 37, 17554 -17561. Link 299 views • 8 upvotes • Written 7 Jan

http://www.jbc.org/content/275/8/5620.full.pdf+html The Role of Tryptophan Residues in the 5-

Hydroxytryptamine3 Receptor Ligand Binding Domain* “The 5-HT3 1 receptor is a member of the Cys

loop family of ligand-gated ion channels, which includes nicotinic acetylcholine (nACh), g-aminobutyric

acid (GABA), and glycine receptors . . . The nACh receptor is the receptor most closely related to the 5-

HT3 receptor with up to 30% amino acid sequence identity(5) . . . Labeling and mutagenesis studies have

identified a number of N-terminal amino acids in nACh subunits that are probably involved in ligand

binding; these are mostly aromatic amino acids and include Trpa54, Trpa86, Tyra93, Trpa149, Trpa187,

Tyra190, Cysa192, Cysa193, and Tyra198 (12–25). Sequence alignments between the nACh and 5-HT3

receptors show that some of the tryptophan residues are conserved in both classes of receptor. These

include nACh Trpa54, Trpa86, and Trpa149, which align to residues Trp90, Trp121, and Trp183 in the 5-

HT3A receptor subunit. Biochemical evidence also indicates that tryptophan residues are involved in 5-

HT3 receptor ligand binding; modifying these residues with N-bromosuccinimide inhibits radiolabeled

antagonist binding to the 5-HT3 receptor in a ligand-protectable manner (26). To examine the role of

tryptophan residues in the N-terminal ligand binding domain of the 5-HT3A receptor, we have changed

the eight tryptophans in this region (Fig. 1) using site-directed mutagenesis . . . Combining the findings

from mutations at Trp90, Trp183, and Trp195, we can postulate that the cationic ligands of the 5-HT3

receptor interact with these aromatic residues, probably via cation p interactions, with Trp183 likely to

be the principle tryptophan in the binding site. The homology between these putative ligand binding

amino acids and the other members of the Cys loop family, demonstrates that tertiary folding of the N-

terminal domain for these receptors is highly conserved . . . In summary, we have systematically

examined the roles played by all of the tryptophan residues in the N-terminal ligand binding domain of

the 5-HT3 receptor. A combination of radioligand binding, electrophysiological assays, and

immunolocalization experiments allowed the identification of functionally significant residues in ligand

binding, Trp90, Trp183, and Trp195, and those implicated in receptor structure and/or assembly, Trp95,

Trp102, Trp121, and Trp214. The findings of this study further exemplify the high degree of structural

and functional homology between the receptors in the Cys loop LGIC family and provide insights toward

the subtle differences that may be responsible for the characteristic 5-HT3 receptor ligand binding

profile.

https://en.wikipedia.org/wiki/Cys-loop_receptors Wiki

References 13 website: JMR, http://fluoroquinolonethyroid.com

https://en.wikipedia.org/wiki/5-HT3_receptor “The 5-HT3 receptor belongs to the Cys-loop superfamily

of ligand-gated ion channels (LGICs) and therefore differs structurally and functionally from all other 5-

HT receptors (5-hydroxytryptamine, or serotonin) receptors which are G protein-coupled

receptors.[1][2][3] This ion channel is cation-selective and mediates neuronal depolarization and

excitation within the central and peripheral nervous systems.[1] As with other ligand gated ion channels,

the 5-HT3 receptor consists of five subunits arranged around a central ion conducting pore, which is

permeable to sodium(Na), potassium(K), and calcium(Ca) ions. Binding of the neurotransmitter 5-

hydroxytryptamine (serotonin) to the 5-HT3 receptor opens the channel, which, in turn, leads to an

excitatory response in neurons. The rapidly activating, desensitizing, inward current is predominantly

carried by sodium and potassium ions.[2] 5-HT3 receptors have a negligible permeability to anions.[1]

They are most closely related by homology to the nicotinic acetylcholine receptor . . . The 5-HT3 receptor

differs markedly in structure and mechanism from the other 5-HT receptor subtypes, which are all G-

protein-coupled . . . The 5-HT3 receptor gene is located on human chromosomal region 11q23.1-q23.2. It

has been 9 exons in the mouse genome and is spread over ~13 kb. Interestingly, four of its introns are

exactly in the same position as the introns in the homologous α7-Acetylcholine receptor gene, clearly

proving their evolutionary relationship.[10][11] Genes that code for the subunits of the 5-HT3 receptor

have been identified. HTR3A and HTR3B for the 5-HT3A and 5-HT3B subunits and in addition HTR3C,

HTR3D and HTR3E genes encoding 5-HT3C, 5-HT3D and 5-HT3E subunits . . . The 5-HT3 receptor is

expressed throughout the central and peripheral nervous systems and mediates a variety of physiological

functions.[13] On a cellular level, it has been shown that postsynaptic 5-HT3 receptors mediate fast

excitatory synaptic transmission in rat neocortical interneurons, amygdala, and hippocampus, and in

ferret visual cortex.[14][15][16][17] 5-HT3 receptors are also present on presynaptic nerve terminals.

There is some evidence for a role in modulation of neurotransmitter release, [18][19]but evidence is

inconclusive.[20]. When the receptor is activated to open the ion channel by agonists, the following

effects are observed: CNS: nausea and vomiting center in brain stem, anxiety,[21] seizure propensity [22]

PNS: neuronal excitation (in autonomic, nociceptive neurons), emesis[21]

https://en.wikipedia.org/wiki/5-HT_receptor “The serotonin receptors, also known as 5-

hydroxytryptamine receptors or 5-HT receptors, are a group of G protein-coupled receptors (GPCRs) and

ligand-gated ion channels (LGICs) found in the central and peripheral nervous systems.[1][2] They

mediate both excitatory and inhibitory neurotransmission. The serotonin receptors are activated by the

neurotransmitter serotonin, which acts as their natural ligand.

The serotonin receptors modulate the release of many neurotransmitters, including glutamate, GABA,

dopamine, epinephrine / norepinephrine, and acetylcholine, as well as many hormones, including

oxytocin, prolactin, vasopressin, cortisol, corticotropin, and substance P, among others. The serotonin

receptors influence various biological and neurological processes such as aggression, anxiety, appetite,

cognition, learning, memory, mood, nausea, sleep, and thermoregulation. The serotonin receptors are

the target of a variety of pharmaceutical drugs, including many antidepressants, antipsychotics,

anorectics, antiemetics, gastroprokinetic agents, antimigraine agents, hallucinogens, and

entactogens.[3]

References 13 website: JMR, http://fluoroquinolonethyroid.com

https://en.wikipedia.org/wiki/Aromatic_amino_acids Aromatic amino acids “Animals get aromatic

amino acids from diet, but all plants and micro-organisms must synthesize their aromatic amino acids

through the metabolically costly shikimate pathway in order to make proteins. Herbicides and antibiotics

work by inhibiting enzymes involved in aromatic acid synthesis, thereby rendering them toxic to plants

and micro-organisms but not to animals.”

https://en.wikipedia.org/wiki/Tryptophan “Only the L-stereoisomer of tryptophan is used in structural or

enzyme proteins, but the R-stereoisomer is occasionally found in naturally produced peptides (for

example, the marine venom peptide contryphan).[3] The distinguishing structural characteristic of

tryptophan is that it contains an indole functional group . . . Tryptophan is a routine constituent of most

protein-based foods or dietary proteins. It is particularly plentiful in chocolate, oats, dried dates, milk,

yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas,almonds, sunflower seeds,

pumpkin seeds, spirulina, bananas, and peanuts . . . There was a large outbreak of eosinophilia-myalgia

syndrome (EMS) in the U.S. in 1989, which caused 1,500 cases of permanent disability and at least thirty-

seven deaths . . . It eventually became clear that the cause had not been the tryptophan itself, but rather

that flaws in Showa Denko's 1980s manufacturing process (long since corrected) had allowed trace

impurities to contaminate these batches, and those impurities were in turn responsible for the 1989 EMS

outbreak . . . Tryptophan is an important intrinsic fluorescent probe (amino acid), which can be used to

estimate the nature of microenvironment of the tryptophan. Most of the intrinsic fluorescence emissions

of a folded protein are due to excitation of tryptophan residues.”

https://en.wikipedia.org/wiki/Eosinophilia%E2%80%93myalgia_syndrome Eosinophilia–myalgia

syndrome. “Eosinophilia–myalgia syndrome (EMS) is an incurable and sometimes fatal flu-like

neurological condition thought to be caused by ingestion of poorly produced L-tryptophan dietary

supplements.[1][2] Similar to regular eosinophilia, there is an increase in the number of eosinophil

granulocytes in the blood.”

https://en.wikipedia.org/wiki/Indole Indole. “Indole is an aromatic heterocyclic organic compound. It

has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-

containing pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a

variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial

physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and

virulence.[1] The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter

serotonin.[2] . . . Indole is a solid at room temperature. Indole can be produced by bacteria as a

degradation product of the amino acid tryptophan. It occurs naturally in human feces and has an intense

fecal odor. At very low concentrations, however, it has a flowery smell,[3] and is a constituent of many

flower scents (such as orange blossoms) and perfumes. It also occurs in coal tar.”

https://en.wikipedia.org/wiki/Cation%E2%80%93pi_interaction From Wiki:

Cation-pi interactions: Cation–π interactions in nature[edit]

Nature’s building blocks contain aromatic moieties in high abundance. Recently, it has become

clear that many structural features that were once thought to be purely hydrophobic in nature are

References 13 website: JMR, http://fluoroquinolonethyroid.com

in fact engaging in cation–π interactions. The amino acid side chains of phenylalanine,

tryptophan, tyrosine, histidine, are capable of binding to cationic species such as charged amino

acid side chains, metal ions, small-molecule neurotransmitters and pharmaceutical agents. In

fact, macromolecular binding sites that were hypothesized to include anionic groups (based on

affinity for cations) have been found to consist of aromatic residues instead in multiple cases.

Cation-π interactions can tune the pKa of nitrogenous side-chains, increasing the abundancy of

the protonated form, this has implications for protein structure and function.[15] While less studied

in this context, the DNA bases are also able to participate in cation–π interactions.[16][17]

Role in protein structure[edit]

Early evidence that cation–π interactions played a role in protein structure was the observation

that in crystallographic data, aromatic side chains appear in close contact with nitrogen-

containing side chains (which can exist as protonated, cationic species) with disproportionate

frequency.

A study published in 1986 by Burley and Petsko looked at a diverse set of proteins and found

that ~ 50% of aromatic residues Phe, Tyr, and Trp were within 6Å of amino groups.

Furthermore, approximately 25% of nitrogen containing side chains Lys, Asn, Gln, and His were

within van der Waals contact with aromatics and 50% of Arg in contact with multiple aromatic

residues (2 on average).[18]

Studies on larger data sets found similar trends, including some dramatic arrays of alternating

stacks of cationic and aromatic side chains. In some cases the N-H hydrogens were aligned

toward aromatic residues, and in others the cationic moiety was stacked above the π system. A

particularly strong trend was found for close contacts between Arg and Trp. The guanidinium moiety of Arg in particular has a high propensity to be stacked on top of aromic residues while

also hydrogen-bonding with nearby oxygen atoms.[19][20][21]

Molecular recognition and signaling[edit]

Cationic Acetylcholine binding to a tryptophan residue of the nicotinamide acetylcholine receptor via a

cation–π effect.

An example of cation–π interactions in molecular recognition is seen in the nicotinic

acetylcholine receptor (nAChR) which binds its endogenous ligand, acetylcholine (a positively

charged molecule), via a cation–π interaction to the quaternary ammonium. The nAChR

neuroreceptor is a well-studied ligand-gated ion channel that opens upon acetylcholine binding.

References 13 website: JMR, http://fluoroquinolonethyroid.com

Acetylcholine receptors are therapeutic targets for a large host of neurological disorders,

including Parkinson's disease, Alzheimer's disease, schizophrenia, depression and autism.

Studies by Dougherty and coworkers confirmed that cation-π interactions are important for

binding and activating nAChR by making specific structural variations to a key tryptophan

residue and correlating activity results with cation-π binding ability.[22]

The nAChR is especially important in binding nicotine in the brain, and plays a key role in

nicotine addiction. Nicotine has a similar pharmacophore to acetylcholine, especially when

protonated. Strong evidence supports cation-π interactions being central to the ability of nictotine

to selectivity activate brain receptors without affecting muscle activity. [23][24]

A further example is seen in the plant UV-B sensing protein UVR8. Several trpytophan residues

ineract via Cation-π interactions with arginine residues which in turn form salt bridges with

acidic residues on a second copy of the protein. It has been proposed[25] that absorption of a

photon by the trytophan residues disrupts this interaction and leads to dissociation of the protein dimer.

Cation-π binding is also thought to be important in cell-surface recognition[2][26]

Enzyme catalysis[edit]

Cation-π interactions can catalyze chemical reactions by stabilizing buildup of positive charge in

transition states. This kind of effect is observed in enzymatic systems. For example,

acetylcholine esterase contains important aromatic groups that bind quaternary ammonium in its

active site.[2]

http://www.ncbi.nlm.nih.gov/pubmed/7260125 [The inherent fluorescence of thyroglobulin]. “It has

been shown that practically all (95%) tryptophane residues in "normal" thyroglobulin are in the inner

regions of the globule. In "pathological" thyroglobulin in the regions inaccessible for water there are

located only 68% of trypthophanyls”

http://www.ncbi.nlm.nih.gov/pubmed/1936269 Acetylcholine interactions with tryptophan-184 of the

alpha-subunit of the nicotinic acetylcholine receptor revealed by transferred nuclear Overhauser effect.

https://en.wikipedia.org/wiki/Acetylcholinesterase “AChE has a very high catalytic activity - each

molecule of AChE degrades about 25000 molecules of acetylcholine (ACh) per second, approaching the

References 13 website: JMR, http://fluoroquinolonethyroid.com

limit allowed by diffusion of the substrate.[2][3] The active site of AChE comprises 2 subsites - the anionic

site and the esteratic subsite. The structure and mechanism of action of AChE have been elucidated from

the crystal structure of the enzyme.[4][5]

The anionic subsite accommodates the positive quaternary amine of acetylcholine as well as other

cationic substrates and inhibitors. The cationic substrates are not bound by a negatively charged amino

acid in the anionic site, but by interaction of 14 aromatic residues that line the gorge leading to the

active site.[6][7][8] All 14 amino acids in the aromatic gorge are highly conserved across different

species.[9] Among the aromatic amino acids, tryptophan 84 is critical and its substitution with alanine

results in a 3000-fold decrease in reactivity.[10] The gorge penetrates half way through the enzyme and

is approximately 20 angstroms long. The active site is located 4 angstroms from the bottom of the

molecule.[11]

The esteratic subsite, where acetylcholine is hydrolyzed to acetate and choline, contains the catalytic

triad of three amino acids: serine 200, histidine 440 and glutamate 327. These three amino acids are

similar to the triad in other serine proteases except that the glutamate is the third member rather than

aspartate. Moreover, the triad is of opposite chirality to that of other proteases.[12] The hydrolysis

reaction of the carboxyl ester leads to the formation of an acyl-enzyme and free choline. Then, the acyl-

enzyme undergoes nucleophilic attack by a water molecule, assisted by the histidine 440 group,

liberating acetic acid and regenerating the free enzyme.

It has also been shown that the main active ingredient in cannabis, tetrahydrocannabinol, is a

competitive inhibitor of acetylcholinesterase.[30]”

http://www.ebi.ac.uk/pdbe/quips?story=AChE Acetylcholinesterase: A gorge-ous enzyme. “Before the

structure was solved, it was known that there were two binding sites for the positively charged (cationic)

substrate, which were termed anionic sites. The structure showed that these sites both lie within the

gorge but neither is actually anionic. They are formed by a group of aromatic residues, predominantly

tryptophans. The ‘peripheral anionic site’ (PAS; view-1) lies at the entrance to the gorge and sequesters

acetylcholine. Acetylcholine forms a π-cation interaction with the tryptophan, and the carbonyl of the

acetyl group forms a weak hydrogen bond to a tyrosine further down the gorge. Acetylcholine, or the

substrate analogue acetylthiocholine (PDB entries 2ha4, 2c4h, 2c58), is only observed at this site when

high concentrations were present in the crystallisation solution, indicating that the PAS is only occupied

transiently.

At the base of the gorge, a second tryptophan plays a key role in the ‘catalytic anionic site’ (CAS). Again,

acetylcholine forms a π-cation interaction between its quaternary amine and the tryptophan ring. The

acetyl group is bound in the acyl pocket, formed from further aromatic residues lining the base of the

gorge.

Between the two anionic sites, the gorge narrows due to a constriction formed by two aromatic

sidechains (view-1). The constriction is smaller than acetylcholine, indicating that the protein must

undergo considerable conformational changes locally to widen the gorge and let the substrate through.

References 13 website: JMR, http://fluoroquinolonethyroid.com

Drugs: Making a little go a long way.

Several drugs which inhibit AChE, some derived from plants, are used clinically to treat the symptoms of

dementia. In diseases such as Alzheimer’s, certain types of brain cell produce too little acetylcholine,

which they use as a neurotransmitter. Inhibiting AChE means that what little neurotransmitter is

produced can deliver its message more times before it is broken down. The side-effects of these drugs

include nausea and vomiting (also symptoms of sublethal sarin poisoning) so it is easy to see why they

act as a plant defence against herbivores.

Other drugs block the active site but do not react with the enzyme. Huprine (e.g., PDB entries 1e66,

4bdw) is a synthetic derivative of huperzine (PDB entries 1vot, 1gpk, 4ey5), extracted from a moss which

has been used in Chinese medicine for centuries. Galanthamine (e.g., PDB entries 1w6r, 4ey6), first

isolated from snowdrops (Galanthus sp), is a bulky molecule like huperzine. It interacts with both the PAS

and the acyl-binding pocket (view-3), competing with acetylcholine for the active site. Galanthamine is

also taken to promote lucid dreams and out-of-body experiences, but whether its anti-cholinesterase

activity or some other property causes these effects is not known.

Tacrine (PDB entry 1acj) is a synthetic molecule that binds only to the CAS (view-3) and does not interact

with residues around the active site. Donepezil (also known as aricept) is bivalent, interacting with both

the CAS and PAS tryptophans (view-3) via ring-stacking interactions (PDB entries 4ey7, 1eve). Donezepil

is a 20-fold more potent inhibitor of AChE than tacrine. In the USA alone, the market for donezepil was

$2.5 billion in 2010.

AChE: a target of many different molecules

AChE is an essential component of the nervous system. Some snakes have found a way to inhibit this

enzyme to help immobilise their prey, and some plants have molecules which inhibit it just enough to

discourage animals from eating them. Mankind has targeted AChE in the treatment of disease, to kill

pests, and also to kill other humans. The 2009 IgNobel Prize in Public Health was awarded for a means of

avoiding chemical weapons, presumably including sarin which targets AChE, whilst the 2013 Nobel Peace

Prize was awarded to the Organisation for the Prohibition of Chemical Weapons "for its extensive efforts

to eliminate chemical weapons."

http://www.ncbi.nlm.nih.gov/pubmed/2650665 Robberecht W, Bednarik J, Bourgeois P, et al.

Myasthenic syndrome caused by direct effect of chloroquine on neuromuscular junction. Arch Neurol

1989;46:464-468.

http://www.ncbi.nlm.nih.gov/pubmed/8814892 Sieb JP, Milone M, Engel AG. Effects of the quinoline

derivatives quinine, quinidine, and chloroquine on neuromuscular transmission. Brain Res

1996;712:179-189.

http://www.ncbi.nlm.nih.gov/pubmed/10612109 Klimek A. The myasthenic syndrome after

chloroquine. Neurol Neurochir Pol 1999;33:951-954.

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pubmed/3343986 Sghirlanzoni A, Mantegazza R, Mora M, et al.

Chloroquine myopathy and myasthenia-like syndrome. Muscle Nerve 1988;11:114-119.

20. Bruggemann W, Herath H, Ferbert A. Follow-up and immunologic findings in drug-induced

myasthenia. Med Klin 1996;91:268-271.

21. Penn AS, Low BW, Jaffe IA, et al. Drug-induced autoimmune myasthenia gravis. Ann N Y Acad Sci

1998;841:433-449.

22. Adams SL, Mathews J, Grammer LC. Drugs that may exacerbate myasthenia gravis. Ann Emerg Med

1984;13:532-538.

http://neuromuscular.wustl.edu/mtime/mgdrug.html MYASTHENIC

SYNDROMES: DRUG-INDUCED

CLINICAL PATTERNS

Rapid Onset

Development of prominent myasthenic signs within days Anti-AChR antibodies absent Rapid disappearance after drug withdrawal Probably related to unmasking of pre-existing disorder of neuromuscular transmission

Exacerbation of Myasthenia Gravis

Develops after days to weeks Clinical patterns

o Subclinical myasthenia gravis becomes manifest after drug treatment Post-operative respiratory depression Myasthenia gravis becomes chronically present

o Known myasthenia becomes more severe Anti-AChR antibodies often present Drugs with clear effects on myasthenia:

o General None of these drugs is absolutely contra-indicated in myasthenia If important to treat a serious disorder

o Monitor myasthenia carefully: Especially respiration & swallowing o If new or more severe myasthenic signs develop:

Treat & consider stopping the medication if necessary o Antibiotics

Neomycin Streptomycin Gentamicin Colisitins Telithromycin: Exacerbation within 2 hours of administration6

References 13 website: JMR, http://fluoroquinolonethyroid.com

? Kanamycin o Anti-rheumatic

Prednisone (High dose): Onset days after administration Chloroquine

o NMJ blockers Curare Non-depolarizing (Vecuronium) Botulinum toxin

o Other Quinidine Procainamide Procaine Magnesium β-blockers ? Phenytoin Statins8

Other drugs with anecdotal reports of MG exacerbation o Antibiotics: Tobramycin; Amikacin; Polymyxin B; Tetracyclines; Lincomycin;

Clindamycin; Erythromycin; Ampicillin;

Fluoroquinolones (Norfloxacin, Ofloxacin, Pefloxacin Reduced MEPP amplitude) o Other: Verapamil; Trimethaphan; Trimethadione; Lithium; Chlorpromazine;

Trihexyphenidyl; D,L-carnitine; Bretylium; Emetine; Lactate; Methoxyflurane; Contrast agents; Citrate anticoagulant; Trasylol; Gabapentin

Drug-induced MG: Slow Onset

New immune-mediated myasthenia gravis induced by drug treatment Onset: Weeks to months after drug treatment Slow & possibly incomplete recovery after drug cessation Anti-AChR antibodies may be present Specific drugs

o Penicillamine Associated with HLA-DR1 Clinical: Similar to other autimmune MG Remits on withdrawal of drug May also produce myositis & neuromyotonia

o Other drugs Diphenylhydantoin Chloroquine Quinidine Trimethadone Procainamide Tandutinib Ipilimumab

References 13 website: JMR, http://fluoroquinolonethyroid.com

https://en.wikipedia.org/wiki/Neopterin Neopterin. Neopterin is a catabolic product of guanosine

triphosphate (GTP), a purine nucleotide. Neopterin belongs to the chemical group known as pteridines.

It is synthesised by human macrophages upon stimulation with the cytokine interferon-gamma and is

indicative of a pro-inflammatory immune status. Neopterin serves as a marker of cellular immune

system activation.

Neopterin as disease marker[edit]

Measurement of neopterin concentrations in body fluids like blood serum, cerebrospinal fluid or urine

provides information about activation of cellular immune activation in humans under the control of T

helper cells type 1. High neopterin production is associated with increased production of reactive

oxygen species, neopterin concentrations also allow to estimate the extent of oxidative stress elicited by

the immune system.

Increased neopterin production is found in, but not limited to, the following diseases:

viral infections including human immunodeficiency virus (HIV), hepatitis B and hepatitis C

bacterial infections by intracellular living bacteria such as Borrelia (Lyme Disease), Mycobacterium

tuberculosis and Helicobacter pylori.

parasites such as Plasmodium (malaria)

autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE)

malignant tumor diseases

allograft rejection episodes.

A leukodystrophy called Aicardi-Goutieres syndrome[1]

depression and somatization.

Neopterin concentrations usually correlate with the extent and activity of the disease, and are also

useful to monitor during therapy in these patients. Elevated neopterin concentrations are among the

best predictors of adverse outcome in patients with HIV infection, in cardiovascular disease and in

various types of cancer.

In the laboratory it is measured by radioimmunoassay (RIA), ELISA, or high-performance liquid

chromatography (HPLC). It has a native fluorescence of wavelength excitation at 353 nm and emission at

438 nm, rendering it readily detected.

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.neopterin.net/neopterin_e.pdf Neopterin info – good website. “Beyond that,

measurement of neopterin levels does not solely reflect the effect of one single cytokine, rather it

allows to determine the total effect of the immunological network and interactions on the population of

monocytes/ macrophages. The reflection of the multiple cooperations between immunocompetent cells

seems to be the basis for the remarkable value of neopterin analyses as an immunodiagnostic tool . . .

Neopterin is a low molecular weight substance which is biologically and chemically stable in body fluids,

and it can be applied without difficulty for routine measurements in laboratory diagnosis. Neopterin is

eliminated by the kidney, and changes of neopterin concentrations in serum are reflected by urine levels

[30] as long as renal function is not impaired. In fact, there is an equal sensitivity of neopterin

measurements either in serum or urine. Measurement of 7,8-dihydroneopterin is not suitable for

routine application in laboratory diagnosis [29]. This derivative is chemically unstable and easily

decomposes due to oxidation, so that more stringent criteria for sample collection and handling restrict

its usefulness as a clinical diagnostic. Because also neopterin is slightly sensitive to direct sun light

irradiation, samples must be protected from light during transport and storage. In general enveloping of

the samples, e.g. in aluminum foil, is sufficient, alternatively dark tubes may be used for collecting

samples . . . Because of its formation during the course of cell-mediated immune response neopterin

monitoring allows to determine the effects of therapeutical interventions which are assigned to

interfere with the degree of immune activation. Particularly in therapies with cytokines such as

interferons, interleukins or tumor necrosis factor-α a dose-dependent increase of neopterin occurs, so

that monitoring of neopterin concentrations allows to define an optimal dosage of immune-modulating

therapy

http://www.ncbi.nlm.nih.gov/pubmed/7865624 Eur J Clin Chem Clin Biochem. 1994 Sep;32(9):685-9.

Neopterin production and tryptophan degradation in acute Lyme

neuroborreliosis versus late Lyme encephalopathy. Gasse T1, Murr C, Meyersbach P, Schmutzhard E, Wachter H, Fuchs D.

Author information

1Klinik für Neurologie, Universität Innsbruck, Austria.

Abstract

Fourteen patients with Borrelia burgdorferi infection were investigated for possible abnormalities of tryptophan and neopterin metabolism. Four patients (2 were investigated before therapy, 2 when therapy had been already started) had acute Lyme neuroborreliosis, and 10 patients were investigated months to years after an acute infection. Increased concentrations of neopterin and of the tryptophan-degradation product, L-kynurenine, were detected in the cerebrospinal fluid of patients with acute Lyme neuroborreliosis; one patient presented with subnormal tryptophan. Similar but less marked changes were seen in the treated patients and in some of the patients with Lyme encephalopathy. No such abnormalities were seen in the serum of the patients. The data indicate a role of the immune system and

References 13 website: JMR, http://fluoroquinolonethyroid.com

particularly of endogenously formed cytokines, like interferon-gamma and tumour necrosis factor-alpha, effecting tryptophan and neopterin metabolism in patients with acute Lyme neuroborreliosis.

PMID:

7865624

[PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/12401473

Brain Behav Immun. 2002 Oct;16(5):590-5.

Neopterin production, tryptophan degradation, and mental

depression--what is the link? Widner B1, Laich A, Sperner-Unterweger B, Ledochowski M, Fuchs D.

Author information

1Institute of Medical Chemistry and Biochemistry, University of Innsbruck, Fritz Pregl Strasse 3, Innsbruck A-6020, Austria.

Abstract

The cytokine interferon-gamma stimulates human monocytes/macrophages to release large amounts of neopterin. Increased neopterin concentrations in body fluids of patients are observed during diseases with activated cellular (=TH1-type) immune response such as allograft rejection, virus infections, autoimmune disorders, or malignant tumors but also in neurodegenerative diseases or during pregnancy. In various cells interferon-gamma induces indoleamine 2,3-dioxygenase (IDO) which degrades tryptophan via the kynurenine pathway. Therefore like increased neopterin formation, enhanced tryptophan degradation is observed in diseases concomitant with cellular immune activation. Disturbed metabolism of tryptophan affects biosynthesis of neurotransmitter 5-hydroxytryptamine (serotonin), and it appears to be associated with an increased susceptibility for depression. In fact, enhanced neopterin concentrations together with increased degradation of tryptophan and low serum levels of tryptophan correlate with neuropsychiatric abnormalities like cognitive decline and depressive symptoms especially in long-lasting and chronic diseases. Activation of IDO could represent an important link between the immunological network and the pathogenesis of depression.

Copyright 2002 Elsevier Science (USA)

PMID:

12401473

[PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/16139256

References 13 website: JMR, http://fluoroquinolonethyroid.com

Clin Chim Acta. 2006 Feb;364(1-2):82-90. Epub 2005 Sep 1.

Monitoring tryptophan metabolism in chronic immune activation. Schröcksnadel K1, Wirleitner B, Winkler C, Fuchs D.

Author information

1Division of Biological Chemistry, Biocentre, Innsbruck Medical University, Fritz Pregl Strasse 3 A-6020 Innsbruck, Austria.

Abstract

The essential amino acid tryptophan is a constituent of proteins and is also a substrate for two important biosynthetic pathways: the generation of neurotransmitter 5-hydroxytryptamine (serotonin) by tryptophan 5-hydroxylase, and the formation of kynurenine derivatives and nicotinamide adenine dinucleotides. The latter pathway is initiated by the enzymes tryptophan pyrrolase (tryptophan 2,3-dioxygenase, TDO) and indoleamine 2,3-dioxygenase (IDO). TDO is located in liver cells, whereas IDO is expressed in a variety of cells including monocyte-derived macrophages and dendritic cells and is preferentially induced by Th1-type cytokine interferon-gamma. Tryptophan depletion via IDO is part of the cytostatic and antiproliferative activity mediated by interferon-gamma in cells. In vivo tryptophan concentration can be measured by HPLC by monitoring its natural fluorescence (285 nm excitation and 365 nm emission wavelength). IDO activity is characterized best by the kynurenine to tryptophan ratio which correlates with concentrations of immune activation markers such as neopterin. Low serum/plasma tryptophan concentration is observed in infectious, autoimmune, and malignant diseases and disorders that involve cellular (Th1-type) immune activation as well as during pregnancy due to accelerated tryptophan conversion. Thus, in states of persistent immune activation, low tryptophan concentration may contribute to immunodeficiency. Decreased serum tryptophan can also effect serotonin biosynthesis and thus contribute to impaired quality of life and depressive mood. As such, monitoring tryptophan metabolism in chronic immunopathology provides a better understanding of the association between immune activation and IDO and its role in the development of immunodeficiency, anemia and mood disorders.

PMID:

16139256

[PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/7890394

Infect Immun. 1995 Apr;63(4):1356-61.

Identification of an immunologically important hypervariable domain

of major outer surface protein A of Borrelia burgdorferi. McGrath BC1, Dunn JJ, Gorgone G, Guttman D, Dykhuizen D, Luft BJ.

Author information

References 13 website: JMR, http://fluoroquinolonethyroid.com

1Biology Department, Brookhaven National Laboratory, Upton, New York 11973.

Erratum in

Infect Immun 1995 Jun;63(6):2390.

Abstract

The gene for the major outer surface protein A (OspA) from several clinically obtained strains of Borrelia burgdorferi, the cause of Lyme disease, has been cloned, sequenced, and expressed in Escherichia coli by using a T7-based expression system (J. J. Dunn, B. N. Lade, and A. G. Barbour, Protein Expr. Purif. 1:159-168, 1990). All of the OspAs have a single conserved tryptophan at residue 216 or, in some cases, 217; however, the region of the protein flanking the tryptophan is hypervariable, as determined by a moving-window population analysis of ospA from 15 European and North American isolates of B. burgdorferi. Epitope-mapping studies using chemically cleaved OspA and a TrpE-OspA fusion have indicated that this hypervariable region is important for immune recognition. Biophysical analysis, including fluorescence and circular dichroism spectroscopy, have indicated that the conserved tryptophan is buried in a hydrophobic environment. Polar amino acid side chains flanking the tryptophan are likely to be exposed to the hydrophilic solvent. The hypervariability of these solvent-exposed amino acid residues may contribute to the antigenic variation in OspA. To test this, we have performed site-directed mutagenesis to replace some of the potentially exposed amino acid side chains in the B31 protein with the analogous residues of a Borrelia garinii strain, K48. The altered proteins were then analyzed by Western blot (immunoblot) with monoclonal antibodies which bind OspA on the surface of the intact B31 spirochete. Our results indicate that specific amino acid changes near the tryptophan can abolish the reactivity of OspA to these monoclonal antibodies, which is an important consideration in the design of vaccines based on recombinant OspA.

PMID:

7890394

[PubMed - indexed for MEDLINE]

http://s3-eu-west-1.amazonaws.com/thejournalhub/10.15570/archive/1996/3-4/Fuchs.pdf Enhanced

Intrathecal Neopterin Production and Tryptophan Degredation in Patients With Lyme Neuroborreliosis

https://books.google.com/books?id=uHKl-

7XrfucC&pg=PA98&lpg=PA98&dq=borrelia+burgdorferi+tryptophan&source=bl&ots=5BxSSXlWvv&sig=r

8GrCaUtCwRHQ3C4kqW7odi7XRM&hl=en&sa=X&ved=0CEwQ6AEwB2oVChMI3tnEmcvnxgIVUJWICh2qL

Qq6#v=onepage&q=borrelia%20burgdorferi%20tryptophan&f=false From Book “borrelia burgdorferi

surface localized proteins expressed during persistent infections”: Studies to determine the contribution

of individual amino acids to protein-protein binding interactions have shown tryptophan to have the

highest probability to lie within binding domains and to be conserved within these binding domains;

moreover, binding surface interactions are typically due to one or a few amino acids . . . Trp residues

have also been linked with bacterial virulence. Serine and tyrosine, on the other hand, are common

targets for phosphorylation, a process which has been implicated in bacterial virulence; the

References 13 website: JMR, http://fluoroquinolonethyroid.com

phosphorylation of either of these residues can cause conformational changes in target proteins that

may be important for adherence and/or the activation or repression of protein function.

http://www.ncbi.nlm.nih.gov/pubmed/10971578 Cytoprotective antioxidant function of tyrosine and

tryptophan residues in transmembrane proteins. “The transmembrane domains of integral membrane

proteins show an astounding accumulation of tyrosine and tryptophan residues, especially in the region

of the highest lipid density. We found that these residues perform vital antioxidant functions inside lipid

bilayers and protect cells from oxidative destruction. First, tyrosine- and tryptophan-containing peptides

representing stretches from the transmembrane domains of different integral membrane proteins,

including presenilin and the cystic fibrosis transmembrane conductance regulator, prevent oxidative lysis

in clonal and primary cells. Second, long-chain acylated tyrosine and tryptophan, but not phenylalanine

or short-chain acylated derivatives, are potent inhibitors of lipid peroxidation and oxidative cell death.

The antioxidant functions of tyrosine and tryptophan may provide a specific explanation for (a) their

unique transmembrane distribution pattern and (b) the high vulnerability of low-protein neuronal

membranes to oxidative stress, as seen in neurodegenerative disorders.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3149241/ Tryptophan-Lipid Interactions in Membrane

Protein Folding Probed by Ultraviolet Resonance Raman and Fluorescence Spectroscopy. “Aromatic

amino acids of membrane proteins are enriched at the lipid-water interface. The role of tryptophan on

the folding and stability of an integral membrane protein is investigated with ultraviolet resonance

Raman and fluorescence spectroscopy.”

http://jgp.rupress.org/content/130/2/223.full Concerning Tryptophan and Protein–Bilayer Interactions

http://pubs.acs.org/doi/abs/10.1021/jp407542e Single Tryptophan and Tyrosine Comparisons in the N-

Terminal and C-Terminal Interface Regions of Transmembrane GWALP Peptides

http://pubs.acs.org/doi/abs/10.1021/bi980809c The Preference of Tryptophan for Membrane

Interfaces

http://www.sciencedirect.com/science/article/pii/0005273671903324 Membrane structure: The

reactivity of tryptophan, tyrosine and lysine in proteins of the microsomal membrane

http://www.sciencedirect.com/science/article/pii/S0005273607000806 Fluorescence as a method to

reveal structures and membrane-interactions of amyloidogenic proteins. “The power of fluorescence

spectroscopy lies in its broad applicability. Almost all proteins have natural fluorophores, tyrosine and

tryptophan residues, which allow study of changes in protein conformation . . . Tryptophan (Trp) and

tyrosine (Tyr) residues are naturally occurring fluorophores in proteins”

http://www.pitt.edu/~pvdwel/membrane_old.html Membrane Protein-Lipid Interactions. “Many

integral membrane proteins have a membrane spanning region that is characterized by the presence of

predominantly hydrophobic residues, but is flanked by specific characteristic residues. This is illustrated

below for selected membrane proteins crystal structures, where we see a clear pattern of distribution of

References 13 website: JMR, http://fluoroquinolonethyroid.com

the tryptophan and tyrosine residues near the membrane interface, where they appear to act

as interfacial anchors”

http://www.ncbi.nlm.nih.gov/pubmed/12731875 Interfacial anchor properties of tryptophan residues

in transmembrane peptides can dominate over hydrophobic matching effects in peptide-lipid

interactions

http://www.cell.com/biophysj/abstract/S0006-3495(12)01800-0 Comparison of Interfacial Tyrosine,

Tryptophan and Phenylalanine Residues as Determinants of Orientation and Dynamics of

Transmembrane Peptides

http://jid.oxfordjournals.org/content/185/Supplement_1/S46.full Approaches toward the Directed

Design of a Vaccine against Borrelia burgdorferi

http://campother.blogspot.com/2012/04/father-son-developed-drug-which-might.html Father & Son

Develop Drug Which Could Reduce Lyme Excitotoxin

http://www.ncbi.nlm.nih.gov/pubmed/11162837 Tryptophan 95, an amino acid residue of the Caprine

arthritis encephalitis virus vif protein which is essential for virus replication.

http://www.ncbi.nlm.nih.gov/pubmed/22422885 L-tryptophan-kynurenine pathway metabolites

regulate type I IFNs of acute viral myocarditis in mice

http://www.ncbi.nlm.nih.gov/pubmed/8293279 A mechanism of quinolinic acid formation by brain in

inflammatory neurological disease. Attenuation of synthesis from L-tryptophan by 6-chlorotryptophan

and 4-chloro-3-hydroxyanthranilate

http://www.ncbi.nlm.nih.gov/pubmed/8906254 The kynurenine pathway and neurologic disease.

Therapeutic strategies

http://jvi.asm.org/content/85/9/4606.full A Tryptophan-Rich Motif in the Human Parainfluenza Virus

Type 2 V Protein Is Critical for the Blockade of Toll-Like Receptor 7 (TLR7)- and TLR9-Dependent

Signaling

http://jvi.asm.org/content/83/22/11726.full Tryptophan Residues in the Portal Protein of Herpes

Simplex Virus 1 Critical to the Interaction with Scaffold Proteins and Incorporation of the Portal into

Capsids

http://www.ncbi.nlm.nih.gov/pubmed/20686200 Tryptophan kynurenine metabolism as a common

mediator of genetic and environmental impacts in major depressive disorder: the serotonin hypothesis

revisited 40 years later.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4527356/ Tryptophan Catabolism in Chronic Viral

Infections: Handling Uninvited Guests

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756112/ Acute tryptophan depletion in humans: a

review of theoretical, practical and ethical aspects

http://www.eje-online.org/content/150/3/313.long Autoantibodies to human tryptophan hydroxylase

and aromatic L-amino acid decarboxylase

http://www.ncbi.nlm.nih.gov/pubmed/573061 Diurnal variations in plasma concentrations of

tryptophan, tyrosine, and other neutral amino acids: effect of dietary protein intake

http://www.jbc.org/content/246/12/4041.long The Identification of a Tryptophan Residue Essential to

the Catalytic Activity of Bovine Pancreatic Deoxyribonuclease

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2761987/ Immunogenetic Risk and Protective Factors

for the Development of L-Tryptophan–Associated Eosinophilia–Myalgia Syndrome and Associated

Symptoms

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3594632/ Indoleamine 2,3 dioxygenase and metabolic

control of immune responses

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3588179/ Remarkable Role of Indoleamine 2,3-

Dioxygenase and Tryptophan Metabolites in Infectious Diseases: Potential Role in Macrophage-

Mediated Inflammatory Diseases

http://www.nature.com/icb/journal/v81/n4/full/icb200338a.html Tryptophan and the immune

response

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1408312/ Role of the tryptophan residue in the

vicinity of the catalytic center of exonuclease III family AP endonucleases: AP site recognition

mechanism

http://www.nature.com/mp/journal/v12/n7/full/4002004a.html Role of the novel tryptophan

hydroxylase-2 gene in Tourette syndrome (My note: My 23andMe show: rs4565946, my genotype is

CC, which is "moderately higher odds of Tourette's Syndrome". Those with 2 copies of the C version

have over two times the odds of having Tourettes compared to those with one C or no C's.)

http://jhc.sagepub.com/content/17/9/616.long IODI NE AND PERSULFATE AS HISTOCHEMICAL

BLOCKING AGENTS FOR TYROSINE AND TRYPTOPHAN RESIDUES IN HUMAN GINGIVA

http://www.ncbi.nlm.nih.gov/pubmed/20684605 Crystal Structure-Based Selective Targeting of the

Pyridoxal 5′- Phosphate Dependent Enzyme Kynurenine Aminotransferase II for Cognitive Enhancement.

“Fluctuations in the brain levels of the neuromodulator kynurenic acid may control cognitive processes

and play a causative role in several catastrophic brain diseases.”

http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2015186a.html A genome-wide

association study of kynurenic acid in cerebrospinal fluid: implications for psychosis and cognitive

impairment in bipolar disorder

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3021918/ Tryptophan–Kynurenine Metabolism as a

Common Mediator of Genetic and Environmental Impacts in Major Depressive Disorder: The Serotonin

Hypothesis Revisited 40 Years Later

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908021/ L-Tryptophan: Basic Metabolic Functions,

Behavioral Research and Therapeutic Indications

https://lra.le.ac.uk/bitstream/2381/115/1/MalnasiRAL.pdf The Dynamics of a Single Tryptophan

Residue in the Myosin Catalytic Domain

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2144619/ Specificity in substrate binding by protein

folding catalysts: Tyrosine and tryptophan residues are the recognition motifs for the binding of

peptides to the pancreas-specific protein disulfide isomerase PDIp.

http://link.springer.com/article/10.1007%2FBF02708441 Selenium-containing enzymes in mammals:

Chemical perspectives. “It is evident from various studies that two amino acid residues, tryptophan and

glutamine, appear in identical positions in all known members of the GPx family. According to the three-

dimensional structure established for bovine GPx, these residues could constitute a catalytic triad in

which the selenol group of the selenocysteine is both stabilized and activated by hydrogen bonding with

the imino group of the tryptophan (Trp) residue and with the amido group of the glutamine (Gln) residue.

The ID enzymes, on the other hand, do not possess any Trp or Gln residues in close proximity to selenium,

but contain several histidine residues, which may play important roles in the catalysis. The TrxR enzymes

also possess some basic histidines, but the most important amino acid residues are the cysteines which

constitute the internal cofactor systems along with the catalytically active selenocysteine.”

http://www.ncbi.nlm.nih.gov/pubmed/10719389 Thyroid peroxidase activity is inhibited by amino

acids

http://www.ncbi.nlm.nih.gov/pubmed/11867764 Conserved tryptophan in the core domain of

transglutaminase is essential for catalytic activity

http://www.ncbi.nlm.nih.gov/pubmed/1093382 Control of brain monoamine synthesis by diet and

plasma amino acids. “The rates at which monoaminergic neurons in rat brains synthesize their

neurotransmitters depend on the availability of the amino acid precursors tryptophan (for serotonin) and

tyrosine (for dopamine and norepinephrine). The administration of tryptophan, the injection of insulin, or

the consumption of a single protein-free high-carbohydrate meal all elevate brain tryptophan levels and,

soon thereafter, the levels of serotonin and its major metabolite 5-hydroxyindohe acetic acid. The

addition of protein to the meal suppresses the increases in brain tryptophan and serotonin, because

protein contributes to plasma considerably larger amounts of the other neutral amino acids (e.g.,

leucine, phenylahanine) than of tryptophan, and these other amino acids compete with tryptophan for

uptake into the brain. The elevation of brain tyrosine (by injection of the amino acid or consumption of a

single 40% protein meal) accelerates brain catecholamine synthesis, as estimated by measuring brain

dopa accumulation after decarboxylase inhibition, or brain catechohamine accumulation after inhibition

References 13 website: JMR, http://fluoroquinolonethyroid.com

of monoamine oxidase. These observations suggest that serotonin- and catecholamine- containing brain

neurons are normally under specific dietary control.”

http://www.molecularautism.com/content/4/1/16 Decreased tryptophan metabolism in patients with

autism spectrum disorders. “Tryptophan is a precursor of important compounds, such as serotonin,

quinolinic acid, and kynurenic acid, which are involved in neurodevelopment and synaptogenesis. In

addition, quinolinic acid is the structural precursor of NAD+, a critical energy carrier in mitochondria.

Also, the serotonin branch of the tryptophan metabolic pathway generates NADH. Lastly, the levels of

quinolinic and kynurenic acid are strongly influenced by the activity of the immune system. Therefore,

decreased tryptophan metabolism may alter brain development, neuroimmune activity and

mitochondrial function. Our finding of decreased tryptophan metabolism appears to provide a unifying

biochemical basis for ASDs and perhaps an initial step in the development of a diagnostic assay for ASDs

. . . It is reasonable to hypothesize that the observed reduction of tryptophan metabolism in ASD cell

lines may stem from abnormal functions along tryptophan metabolic pathways in the cells. We

therefore mined data generated from a small gene expression profiling study we had conducted

previously to examine this possibility. The study employed the Agilent Whole Human Genome Oligo

Microarrays and RNA extracted from the initial 10 ASD cell lines and 10 controls (Figure 3 and online).

The data indicated that two genes, SLC7A5 and SLC7A8, coding for tryptophan transporter subunits,

expressed in both blood and brain, had reduced expression in all patients (Figures 3 and 4). The

mitochondrial isoform of tryptophanyl tRNA synthetase (WARS2) had significantly reduced expression (P

<0.001) in a majority (6/10) of the ASD cell lines while the cytoplasmic isoform (WARS) showed no

difference in expression levels (Figures 3 and 4, Additional file 5: Table S5). The two main pathways of

tryptophan metabolism lead to the synthesis of serotonin and kynurenine [18]. Tryptophan hydroxylase

is the rate-limiting enzyme in the biosynthesis of serotonin and the gene encoding the isoform 2 of this

enzyme (TPH2) showed significantly reduced expression levels (Figures 3 and 4, Additional file 5: Table

S5). Also, several genes coding for enzymes involved in the kynurenine pathway showed significant

differences (P <0.05) between ASD cell lines and controls. The expression levels of AADAT, HAAO, and

MAOA were reduced in patients with ASDs, while QPRT showed a non-significant trend towards over-

expression (Figure 3 and Additional file 5: Table S5). Not all genes in tryptophan related pathways

exhibited significant expression differences between ASD patients and controls, and each patient

exhibited a different profile for the group of genes examined. However, each of the 10 ASD patients

showed significant differences (P <0.05) from controls in the expression levels of at least 9/15 genes

involved in tryptophan metabolism (Additional file 5: Table S5). . . . Our findings show an abnormal

utilization of tryptophan as energy source in cells from patients with ASDs, suggesting impaired

tryptophan metabolism. Our analysis consisted of three independent sets of experiments in which we

measured NADH production in 87 lymphoblastoid cells derived from ASD patients as compared to 78

controls. The difference between the case–control populations was statistically significant in each of

these experiments. The statistical analysis was performed in a blind fashion with regard to the presence

of ASDs in the patients. The results correlated with the behavioral traits associated with either

syndromal or non-syndromal autism, independent of the genetic background of the individual. The low

level of NADH generation in the presence of tryptophan was not observed in cell lines from patients

with intellectual disability without ASD or schizophrenia, or in conditions showing several similarities

References 13 website: JMR, http://fluoroquinolonethyroid.com

with syndromal ASDs except for the behavioral traits. Metabolism of tryptophan via the serotonin

synthesis pathway leads to production of NADH, while metabolism via the kynurenine-quinolinic acid

pathway leads to the synthesis of NAD+, the precursor of NADH (Figure 4). The decreased level of NADH

generation in the presence of tryptophan may reflect less utilization of tryptophan resulting from

downregulation of metabolic reactions along either of these pathways. Analysis of microarray

expression data previously collected on the initial 10 ASD patient cell lines and 10 controls found

reduced levels of some genes involved in the serotonin and kynurenine pathways in ASD patients. No

two patients exhibited the same expression profile. The enzyme responsible for the conversion of

quinolinic acid to nicotinate D-ribonucleotide (quinolinate phosphoribosyltransferase) showed a trend

towards increased expression, although this was statistically significant in only seven out of the 10 cell

lines analyzed, when each cell line was individually compared to the control group using the Mann–

Whitney one sample test (Additional file 5: Table S5). This enzyme links the tryptophan-kynurenine

pathway to NAD+ biosynthesis (Figure 4) and is produced by a gene (QPRT) mapping to 16p11.2.

Deletions and duplications of this region have been frequently associated with ASDs, suggesting that

abnormal dosage of the genes in 16p11.2 may be responsible for autism features [19]. Pyridoxine and

its metabolite, pyridoxal phosphate, play a critical role as co-factors in both the serotonin and

kynurenine pathways, so their deficiency may affect tryptophan metabolism. Unfortunately, the PM

plates do not contain any compound closely related to pyridoxine. Additionally, our limited microarray

data for the enzymes involved in pyridoxine/pyridoxal phosphate metabolism (PHOSPHO2, PDX, PNPO)

did not show significant differences when compared to controls in any of the 10 patients.. . . The data

presented in this work indicate that cells from patients with ASDs, on average, are less capable of

utilizing tryptophan as an energy source than controls. The finding was consistent in both syndromal and

non-syndromal cases, and was not influenced by age, sex, or genotype of the patients. We believe that

decreased tryptophan metabolism in patients with ASDs may alter metabolic pathways involved in the

regulation of the early stages of brain development (first month of gestation), mitochondrial

homeostasis and immune system activity in the brain. Disruption of such pathways can primarily be

caused either by insufficient serotonin production by placental cells, mitochondrial dysfunction and/or

impaired balance between quinolinic and kynurenic acid in fetal cells. The combined effects of these

events could lead to abnormal organization of neurons (minicolumnopathy), particularly in specific brain

regions (fronto-temporal lobes, limbic system), determining the imbalance between the short- and long-

term circuitry that has been considered to be one of the fundamentals of the ASD neuropathology

[25,40]. Pathogenic events involving one or more branches of such pathways have been described. Even

though the ideal target tissue, brain, could not be investigated, our observation of decreased tryptophan

metabolism in cells from patients with ASDs may provide a unifying model that could help explain the

genetic heterogeneity of ASDs. Our findings perhaps represent a preliminary step in the development of

an array which could be used to provide a quick and reliable screening test for ASDs.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3460668/ A Brief Historic Overview of Clinical

Disorders Associated with Tryptophan: The Relevance to Chronic Fatigue Syndrome (CFS) and

Fibromyalgia (FM).

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pubmed/9397954 Interactions between transport of triiodothyronine

and tryptophan in JAR cells.

http://www.ncbi.nlm.nih.gov/pubmed/10870040 Effect of tryptophan on the early tri-iodothyronine

uptake in mouse thymocytes.

http://www.nature.com/icb/journal/v81/n4/full/icb200338a.html Tryptophan and the immune

response “Tryptophan is an amino acid required by all forms of life for protein synthesis and other

important metabolic functions, but animals do not possess the enzymatic machinery to synthesize it from

simpler molecules. At the level of primary producers, tryptophan is synthesized from molecules such as

phosphoenolpyruvate in bacteria, fungi and plants, and these organisms fuel the tryptophan flux through

the food chain. Because animals are incapable of synthesizing tryptophan, they must ingest it in the form

of proteins, which are then hydrolysed into the constituent amino acids in the digestive system. Dietary

tryptophan is delivered to the liver through the hepatic portal system, and that portion which is not used

for protein synthesis in the liver can then follow one of two basic metabolic fates. First, it can be

distributed to the blood stream to be used for protein synthesis and other functions by cells throughout

the body. Second, it can be degraded in the liver through a series of metabolic steps known collectively as

the kynurenine pathway. In addition to being one of the building blocks for protein synthesis in humans

and animals, tryptophan is also the only source of substrate for the production of several very important

molecules. In the nervous system and gut, tryptophan is a required substrate for the synthesis of

serotonin, whereas in the pineal gland, it is required for the synthesis of melatonin. Also, when niacin

content in the diet is insufficient for metabolic requirements, tryptophan is necessary for the synthesis of

the essential cellular cofactor, nicotinamide adenine dinucleotide (NAD +). The synthesis of NAD + from

tryptophan has long been thought to be a reaction that takes place solely in the liver.

Extensive research has been done in the last several decades on the role of tryptophan metabolism in the

CNS under normal and pathological conditions,1, 2 but the roles served by tryptophan and its

metabolites in the immune system have been far less well examined. In recent years, a clear association

has been made between tryptophan catabolism and inflammatory reactions in a vast array of disease

states. Much of the focus of this research has centred on the kynurenine pathway of tryptophan

degradation occurring in the immune system, rather than in the liver. Despite this recent interest in

extrahepatic kynurenine metabolism, the biological significance of immune-related tryptophan

breakdown remains unclear.”

http://www.ncbi.nlm.nih.gov/pubmed/17900524 Ciprofloxacin interactions with bacterial protein

OmpF: modelling of FRET from a multi-tryptophan protein trimer. “Quinolones are broad-spectrum

antibacterial agents which mechanism of action is the inhibition of DNA gyrase and DNA topoisomerase

IV enzymes that control DNA topology and are vital for bacterial replication [1], [2] and [3]. Access to the

target site is a major determinant of antibacterial activity, with the outer membrane being the major

permeability barrier in Gram negative bacteria [1]. In fact, one of the mechanisms of resistance

developed by the bacterial cell is the process of making more difficult the access of quinolones to their

target of action, by either not expressing or expressing structurally changed outer membrane porins [3]

and [4]. One of those porins, which microbiology studies related to the permeation of some quinolones

References 13 website: JMR, http://fluoroquinolonethyroid.com

through the outer membrane, is OmpF [1], [3], [4], [5] and [6]. Indeed, porin-deficient mutants of

Escherichia coli are resistant to fluoroquinolones, although the role of OmpF, either as a channel or as an

enabler of quinolone diffusion at the OmpF/lipid interface, has not yet been elucidated. The relative

importance, and the different areas of contact of each quinolone with OmpF, is a subject of great

importance in the context of developing new molecules with less resistance problems.

OmpF is a trimer within the membrane and it contains just two tryptophan residues per monomer (Fig.

1), Trp214 at the lipid protein interface and Trp61 at the trimer interface [7]. The protein shows a

maximum of emission at relatively low wavelengths, which suggests that both tryptophans are in

hydrophobic environments. This is confirmed by experiments involving OmpF mutants [7], which lack one

or both Trps.

Ciprofloxacin (CP) (Fig. 2) is a 6-fluoroquinolone antibiotic currently under clinical use for which many

resistances have been reported in a large number of microbial species. The aim of the present study was

to investigate the role of OmpF as a major pathway for CP entry through the outer membrane into the

bacterial cell by analyzing the alteration of OmpF fluorescence in presence of increasing concentration of

CP”

http://www.ncbi.nlm.nih.gov/pubmed/19148694 Fluorescence quenching as a tool to investigate

quinolone antibiotic interactions with bacterial protein OmpF “The outer membrane porin OmpF is an

important protein for the uptake of antibiotics through the outer membrane of gram-negative bacteria;

however, the possible binding sites involved in this uptake are still not recognized. Determination, at the

molecular level, of the possible sites of antibiotic interaction is very important, not only to understand

their mechanism of action but also to unravel bacterial resistance. Due to the intrinsic OmpF

fluorescence, attributed mainly to its tryptophans (Trp(214), Trp(61)), quenching experiments were used

to assess the site(s) of interaction of some quinolone antibiotics. OmpF was reconstituted in different

organized structures, and the fluorescence quenching results, in the presence of two quenching agents,

acrylamide and iodide, certified that acrylamide quenches Trp(61) and iodide Trp(214). Similar data,

obtained in presence of the quinolones, revealed distinct behaviors for these antibiotics, with nalidixic

acid interacting near Trp(214) and moxifloxacin near Trp(61). These studies, based on straightforward

and quick procedures, show the existence of conformational changes in the protein in order to adapt to

the different organized structures and to interact with the quinolones. The extent of reorganization of

the protein in the presence of the different quinolones allowed an estimate on the sites of

protein/quinolone interaction.”

http://www.ncbi.nlm.nih.gov/pubmed/18788798 Facilitated permeation of antibiotics across

membrane channels--interaction of the quinolone moxifloxacin with the OmpF channel. “The

facilitated influx of moxifloxacin through the most abundant channel in the outer cell wall of gram-

negative bacteria was investigated. Molecular modeling provided atomic details of the interaction with

the channel surface, revealed the preferred orientation of the antibiotic along its pathway, and gave an

estimated time necessary for translocation. High-resolution conductance measurements on single OmpF

trimers allowed the passages of individual moxifloxacin molecules to be counted. The average mean

residence time of 50 micros is in agreement with the predicted strong interaction from the modeling. In

References 13 website: JMR, http://fluoroquinolonethyroid.com

contrast, control measurements with nalidixic acid, a hydrophobic antibiotic that rather permeates

across the lipid membrane, revealed a negligible interaction. The spectral overlap of tryptophan with

moxifloxacin was suitable for a FRET study of the protein-antibiotic interaction. Combining molecular

dynamics simulations with selective quenching identified an interaction of moxifloxacin with Trp61 inside

the OmpF channel, whereas nalidixic acid showed preferential interaction with Trp214 on the channel

exterior. An understanding of the detailed molecular interactions between the antibiotic and its

preferred channel may be used to develop new antibiotics with improved uptake kinetics.”

http://www.ncbi.nlm.nih.gov/pubmed/22369436 Antibiotic permeation across the OmpF channel:

modulation of the affinity site in the presence of magnesium

http://www.academia.edu/9066689/Synthesis_characterization_and_biological_evaluation_of_new_de

rivatives_of_ciprofloxacin_and_norfloxacin_of_interesting_biological_activities Synthesis,

characterization and biological evaluation of new derivatives of ciprofloxacin and norfloxacin of

interesting biological activities. “Synthesis of new derivatives of ciprofloxacin and norfloxacin containing

a tryptophan moiety linked to their NH of piperazine moiety forming amides was achieved by reaction of

the carboxyl group of L-tryptophan. The chemical structures of these new compounds were confirmed by

elemental (CHN) and spectral (IR, H NMR) analyses. The minimum inhibitory concentrations (MICs) of

these derivatives and were determined by a serial dilution method using B. Subtilus and E. coli and the

results were comparable and promising, when compared with the parent compounds. The cell viability of

these derivatives was also determined and the antitumor activity against three types of human cancer

cell lines (Breast, Skin and Colorectal) was evaluated. Compound has significant antiproliferative activity

against breast and skin cancer cells, although slightly less active than ciprofloxacin. This result indicated

that the new derivative of tryptophan-ciprofloxacin has selective antitumor activity against cancer cells

and worth further investigation . . . Most of the FQ are highly specific for prokaryotic type II

topoisomerases and they are also very active against eukaryotic topoisomerases II [1-3] . . . Quinolones

represent a large number of antiproliferative agents exhibiting cytotoxicity through DNA interaction [6-

8]. Ciprofloxacin has been shown to induce DNA strand breaks and to be clastogenic in mammalian cells

[9]. It is also known to induce G2M Cells and cycle arrest and apoptosis in a variety of cancer cell lines [4,

10].Ciprofloxacin was found to inhibit tumor cell growth of bladder transitional cell carcinoma and

prostate cancer cell lines [10-12]. Ciprofloxacin acts as an anticancer drug against bladder cancer cells

[11] and is distinguished by its strong inhibition of topoisomerase II. N-piprazinyl derivatives of

ciprofloxacin showed significant cytotoxic activity against human breast tumor cell lines [11]. Indole

nucleus is continuously drawing attention for the development of newer drugs, due to its wide range of

activities, such as anticancer, antibacterial, antifungal, anti-malarial, anticonvulsant and anti-

inflammatory [13-15]. Indole-containing compounds also have appreciable antibacterial activities [13,

16, 17] . . .”

http://www.tandfonline.com/doi/abs/10.1080/00032719.2010.546020#preview Studies of the

Interaction Between Ciprofloxacin and the Hemocyanin from Chinese Mitten Crab “The hydrophobic

and electrostatic interactions played a major role in the binding process of ciprofloxacin-hemocyanin

system. The distance between the tryptophan residues and ciprofloxacin were calculated . . . The

References 13 website: JMR, http://fluoroquinolonethyroid.com

alteration of the environment of tryptophan residues and the secondary protein structure in the presence

of the ciprofloxacin was confirmed . . .”

http://europepmc.org/abstract/med/25127388 Specific and ultrasensitive ciprofloxacin detection by

responsive photonic crystal sensor

http://www.ncbi.nlm.nih.gov/pubmed/16379288 Fluorescence spectroscopy study of humen serum

albumin quenched by levofloxacin. “According to these calculation results, the combination position

between the binding site of Levofloxacin and the tryptophane of HSA is about R = 1.933 nm”

http://www.ncbi.nlm.nih.gov/pubmed/22548526 Triplet excimers of fluoroquinolones in aqueous

media “On the other hand, generation of FQ radical anions absorbing at λ(max) ca. 620 nm has been

observed by an efficient electron transfer reaction from Trp to NFX, PFX, and ANFX (rate constants ca. 1 ×

10(9) M(-1) s(-1)).”

http://www.ncbi.nlm.nih.gov/pubmed/7657608 A mutation in yeast TOP2 homologous to a quinolone-

resistant mutation in bacteria. Mutation of the amino acid homologous to Ser83 of Escherichia coli gyrA

alters sensitivity to eukaryotic topoisomerase inhibitors. “In prokaryotic type II topoisomerases (DNA

gyrases), mutations that result in resistance to quinolones frequently occur at Ser83 or Ser84 of the gyrA

subunit. Mutations to Trp, Ala, and Leu have been identified, all of which confer high levels of quinolone

resistance. Extensive segments of DNA gyrase are homologous to eukaryotic topoisomerase II, and

Ser741 of yeast TOP2 is homologous to Ser83 of prokaryotic DNA gyrA. Introduction of the Ser741-->Trp

mutation into yeast TOP2 confers resistance to 6,8-difluoro-7-(4'-hydroxyphenyl)-1-cyclopropyl- 4-

quinolone-3-carboxylic acid (CP-115,953), a fluoroquinolone with substantial activity against eukaryotic

topoisomerase II, whereas changing Ser741 to either Leu or Ala does not change sensitivity to

quinolones. Interestingly, Ser741-->Trp in the yeast TOP2 also confers hypersensitivity to etoposide.

Sensitivity to intercalating anti-topoisomerase II agents such as amsacrine is not changed by any of the

three mutations. The topoisomerase II protein carrying the Ser741-->Trp mutation was overexpressed

and purified. The purified mutant enzyme had enhanced levels of etoposide stabilized covalent complex

as compared with the wild type enzyme and reduced cleavage with CP-115,953. Unlike the wild type

enzyme, etoposide-stabilized cleavage is not readily reversible by heat. We suggest that Ser741 is near a

binding site for both quinolones and etoposide and that the Ser741-->Trp mutation leads to a more

stable ternary complex between etoposide, DNA, and the mutant enzyme.”

http://www.ncbi.nlm.nih.gov/pubmed/15561817 A mutation in Escherichia coli DNA gyrase conferring

quinolone resistance results in sensitivity to drugs targeting eukaryotic topoisomerase II. (My note: if a

mutation in a prokaryotic TOPO can result in sensitivity of that TOPO to a eukaryotic TOPO inhibitor,

then isn’t it entirely possible that a mutation in a eukaryotic TOPO could result in sensitivity of that

TOPO to a prokaryotic inhibitor [ie, an FQ]?) This is why the TOPO’s of the FQT/FQAD population need

to be studied genomically and enzymatically if possible. “There are several important implications for

the conservation of most determinants of drug sensitivity between prokaryotic and eukaryotic enzymes.

First, drugs targeting topoisomerase II likely bind to regions of the proteins that are very highly

conserved between prokaryotic and eukaryotic enzymes. This is not a surprising conclusion, given the

References 13 website: JMR, http://fluoroquinolonethyroid.com

high degree of homology found throughout many of the type II topoisomerases (56). However, the

previous assumption that drugs such as etoposide acted against the eukaryotic enzyme but not the

prokaryotic enzyme allowed for the possibility that such drugs interact with residues that are not highly

conserved between the two kingdoms. Our results argue against this possibility. Second, our results

support the hypothesis that many topoisomerase II-targeting drugs that lead to elevated levels of

covalent complexes act near the same site.”

http://www.ncbi.nlm.nih.gov/pubmed/11810538 Studies on the binding mechanism of

fluoroquinolones to melanin. “In order to elucidate the binding mechanism of melanin and

fluoroquinolones (ofloxacin, norfloxacin, ciprofloxacin, lomefloxacin, levofloxacin), we investigated the

interaction of fluoroquinolones with compounds such as l-beta-(3,4-dihydroxyphenyl) alanine (l-DOPA),

l-tyrosine, 5-hydroxy-l-tryptophan, l-tryptophan, and l-phenylalanine, which possess the kind of

functional groups that melanin does and are closely related to melanin. The recovery of drugs from the

melanin-drug complexes by metal ions of Li, Na, Ka, Mg, Ca, Ba, Cu, Ni, and Fe was demonstrated.

Smaller and highly charged cations were found to be more effective for this recovery, and magnesium

ions were the most effective of all the ions investigated.”

http://www.ncbi.nlm.nih.gov/pubmed/16641315 Allosteric interactions with muscarinic acetylcholine

receptors: complex role of the conserved tryptophan M2422Trp in a critical cluster of amino acids for

baseline affinity, subtype selectivity, and cooperativity.

http://www.ncbi.nlm.nih.gov/pubmed/7679072 Functional role of proline and tryptophan residues

highly conserved among G protein-coupled receptors studied by mutational analysis of the m3

muscarinic receptor.

http://www.ncbi.nlm.nih.gov/pubmed/24829147 Intracellular localization of the M1 muscarinic

acetylcholine receptor through clathrin-dependent constitutive internalization is mediated by a C-

terminal tryptophan-based motif

http://www.ncbi.nlm.nih.gov/pubmed/26329338 Downregulation of Tryptophan-related Metabolomic

Profile in Rheumatoid Arthritis Synovial Fluid. “Interestingly, the levels of tryptophan metabolites

kynurenine and N'-formylkynurenine, which are involved in immune tolerance, were significantly lower in

RA SF.”

http://www.ncbi.nlm.nih.gov/pubmed/25784130 Discovery and validation of plasma biomarkers for

major depressive disorder classification based on liquid chromatography-mass spectrometry. “. . .

Levels of acyl carnitines, ether lipids, and tryptophan pronouncedly decreased . . . Disturbed pathways,

mainly located in acyl carnitine metabolism, lipid metabolism, and tryptophan metabolism, were clearly

brought to light in MDD subjects.”

http://www.ncbi.nlm.nih.gov/pubmed/8649184 Effect of acute and chronic treatment with

triiodothyronine on serotonin levels and serotonergic receptor subtypes in the rat brain.

References 13 website: JMR, http://fluoroquinolonethyroid.com

“Hyperthyroidism is often associated with behavioral disorders, and thyroid hormones modify receptor

sensitivity as well as the synthesis and/or turnover rate of many neurotransmitters . . . The serotonergic

system could be involved in the complex brain-neurotransmitter imbalance underlying hyperthyroidism-

linked behavioral changes.”

http://www.nature.com/mp/journal/v7/n2/full/4000963a.html Thyroid hormones, serotonin and

mood: of synergy and significance in the adult brain. “Disorders of the thyroid gland are frequently

associated with severe mental disturbances. This intimate association between the thyroid system and

behavior has been the impetus for exploring the effects of thyroid hormones in modulating affective

illness, and the role of the hypothalamic-pituitary thyroid (HPT) axis in the pathophysiology of mood

disorders. Thyroid hormones (TH) have a profound influence on behavior and mood, and appear to be

capable of modulating the phenotypic expression of major affective illness. Thyroid supplementation is

now widely accepted as an effective treatment option for patients with affective disorders . . . Basic and

clinical research of the past three decades has yielded compelling evidence that the serotonergic system

is intimately involved in the pathogenesis of depression. Changes in serotonergic neurotransmission

have been repeatedly associated with the therapeutic response to antidepressant and mood stabilizing

medication. Almost all currently employed treatments for depression, including the tricyclic

antidepressants, the SSRIs, the MAO inhibitors, lithium and ECT, directly or indirectly augment

serotonergic neurotransmission. Another line of evidence derives from the tryptophan-depletion

paradigm, a procedure that lowers central serotonin levels, and which produces a rapid relapse of SSRI-

responsive depression. Other support comes from studies demonstrating lowered levels of 5-

hydroxyindoleacetic acid (5-HIAA), a metabolite of 5-HT whose levels reflect central serotonin activity, in

the CSF in unmedicated depressed patients. In brain imaging studies, clinical depression was associated

with reduced serotonin transporter availability. (Relevant abstracts are presented in the paper)

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-

879X2000000300015&lng=en&nrm=iso&tlng=en Thyroid peroxidase activity is inhibited by amino

acids. “The inhibitory amino acids contain side chains with either sulfur atoms (cysteine and

methionine) or aromatic rings (tyrosine, tryptophan, histidine and phenylalanine).”

http://www.ncbi.nlm.nih.gov/pubmed/22429096 Mitochondrial disturbances, tryptophan metabolites

and neurodegeneration: medicinal chemistry aspects. “Neurodegenerative disorders, e.g. Parkinson's,

Huntington's and Alzheimer's diseases are distinct clinical and pathological entities sharing a number of

leading features in their underlying processes. These common features involve the disturbances in the

normal functioning of the mitochondria and the alterations in the delicate balance of tryptophan

metabolism. The development of agents capable of halting the progression of these diseases is in the

limelight of neuroscience research. This review highlights the role of mitochondria in the development of

neurodegenerative processes with special focus on the involvement of neuroactive kynurenines both as

References 13 website: JMR, http://fluoroquinolonethyroid.com

pathological agents and potential targets and tools for future therapeutic approaches by providing a

comprehensive summary of the main streams of rational drug design and giving an insight into present

clinical achievements.”

http://www.nature.com/nature/journal/v297/n5863/abs/297229a0.html Differential release of

serotonin and histamine from mast cells

http://www.jacionline.org/article/S0091-6749(06)01898-7/abstract Human mast cells are capable of

serotonin synthesis and release

http://onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.1963.tb53697.x/abstract THE ROLE OF

SEROTONIN (5-HYDROXYTRYPTAMINE) IN MAST CELLS

http://academiccommons.columbia.edu/catalog/ac%3A131582 Mast cells affect brain physiology and

behavior

http://www.jimmunol.org/content/177/9/6422.full 5-Hydroxytryptamine Induces Mast Cell Adhesion

and Migration

http://www.ncbi.nlm.nih.gov/pubmed/17123843 In vitro effect of biogenic amines on the hormone

content of immune cells of the peritoneal fluid and thymus. Is there a hormonal network inside the

immune system?

http://www.ncbi.nlm.nih.gov/pubmed/16904953 Plasticity of neuroendocrine-thymus interactions

during ontogeny and ageing: role of zinc and arginine.

http://www.ncbi.nlm.nih.gov/pubmed/23895527 Is there a possible single mediator in modulating

neuroendocrine-thymus interaction in ageing?

http://press.endocrine.org/doi/abs/10.1210/jcem-45-1-123 Effect of the Serotonin Precursor,

Tryptophan, on Pituitary Hormone Secretion

http://www.ncbi.nlm.nih.gov/pubmed/16075385 Cytokine regulation of tryptophan metabolism in the

hypothalamic-pituitary-adrenal (HPA) axis: implications for protective and toxic consequences in

neuroendocrine regulation

http://www.psyneuen-journal.com/article/0306-4530(79)90038-6/fulltext?mobileUi=0 l-Tryptophan

treatment and the episodic secretion of pituitary hormones and cortisol

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pubmed/15050105 How HIV-1 causes AIDS: implications for prevention

and treatment. HIV-1 encodes for one of the human glutathione peroxidases. As a consequence, as it is

replicated, its genetic needs cause it to deprive HIV-1 seropositive individuals not only of glutathione

peroxidase, but also of the four basic components of this selenoenzyme, namely selenium, cysteine,

glutamine, and tryptophan. Eventually this depletion process causes severe deficiencies of all these

substances. These, in turn, are responsible for the major symptoms of AIDS which include immune

system collapse, greater susceptibility to cancer and myocardial infarction, muscle wasting, depression,

diarrhea, psychosis and dementia. As the immune system fails, associated pathogenic cofactors become

responsible for a variety of their own unique symptoms. Any treatment for HIV/AIDS must, therefore,

include normalization of body levels of glutathione, glutathione peroxidase, selenium, cysteine, glutamine,

and tryptophan. Although various clinical trials have improved the health of AIDS patients by correcting

one or more of these nutritional deficiencies, they have not, until the present, been addressed together.

Physicians involved in a selenium and amino-acid field trial in Botswana, however, are reporting that this

nutritional protocol reverses AIDS in 99% of patients receiving it, usually within three weeks.

http://www.bibliotecapleyades.net/salud/esp_salud02b.htm More about the above

From https://en.wikipedia.org/wiki/Glutaric_aciduria_type_1 Like many other organic

acidemias, GA1 causes carnitine depletion.[5] Whole-blood carnitine can be raised by oral

supplementation. However, this does not significantly change blood concentrations of

glutarylcarnitine or esterified carnitine,[4] suggesting that oral supplementation is suboptimal in

raising tissue levels of carnitine. In the field of clinical nutrition, researchers come to the same

conclusion, that oral carnitine raises plasma levels but doesn't affect muscle carnitine, where

most of it is stored and used.[6]

In contrast, regular intravenous infusions of carnitine caused distinct clinical improvements: "decreased frequency of decompensations, improved growth, improved muscle strength and decreased reliance on medical foods with liberalization of protein intake."[5]

Choline increases carnitine uptake and retention.[7] Choline supplements are inexpensive, safe (probably even in all children requiring anticholinergics) and can provide spectacular evidence of the suboptimal efficiency of carnitine supplementation by increasing exercise tolerance, truncal tone and general well-being.

https://www.ncbi.nlm.nih.gov/pubmed/7616311 Choline supplementation alters carnitine homeostasis

in humans and guinea pigs.

https://www.ncbi.nlm.nih.gov/pubmed/8644685 Choline supplementation reduces urinary carnitine

excretion in humans.

References 13 website: JMR, http://fluoroquinolonethyroid.com

http://www.ncbi.nlm.nih.gov/pubmed/12504925 Acetyl-l-carnitine induces muscarinic antinocieption

in mice and rats. “The analgesic activity of acetyl-L-carnitine (ALCAR) in neuropathic pain is well

established . . . ALCAR was also able to reverse hyperalgesia induced by kainic acid and NMDA

administration in the mouse hot-plate test. The antinociception produced by ALCAR was prevented by

the unselective muscarinic antagonist atropine, the M(1) selective antagonists pirenzepine and S-(-)-

ET126, and by the choline uptake inhibitor hemicholinium-3 (HC-3).”

http://www.ncbi.nlm.nih.gov/pubmed/7646490 Effect of gamma-aminobutyric acid on the carnitine

metabolism in neural cells.

http://www.ncbi.nlm.nih.gov/pubmed/8768311 Carnitine--a known compound, a novel function in

neural cells. “The presence of a carnitine carrier in the inner mitochondrial membrane has been proven

and the protein has been purified. It is postulated that its major role in adult brain would be

translocation of acetyl moieties from mitochondria into the cytoplasm for acetylcholine synthesis. The

latter process is stimulated by carnitine and choline in a synergistic way in cells utilizing glucose as the

main energetic substrate.”

http://www.ncbi.nlm.nih.gov/pubmed/7630861 Inhibition of L-carnitine uptake into primary rat cortical

cell cultures by GABA and GABA uptake blockers.

http://www.ncbi.nlm.nih.gov/pubmed/8817642 Structural, metabolic and ionic requirements for the

uptake of L-carnitine by primary rat cortical cells. “We have shown before that the uptake of L-carnitine

into cultured rat cortical neurones was dependent on temperature as well as the Na gradient and is

inhibited by compounds resembling its structure, like gamma-aminobutyric acid (GABA), but most

potently by specific GABA uptake blockers . . . The uptake of L-C was also significantly inhibited by

structurally-related compounds, with a carbon chain length of three to six atoms, possessing an amine

group and/or a carboxyl group.

http://www.ncbi.nlm.nih.gov/pubmed/17977676 The inhibitory effects of fluoroquinolones on L-

carnitine transport in placental cell line BeWo. “The aim of this study was to determine the effects of

fluoroquinolones, inhibitors of OCTN2, on L-carnitine transport in the placenta which is known to have a

high expression level of OCTN2. We investigated the inhibitory effect of five fluoroquinolones,

ciprofloxacin (CPFX), gatifloxacin (GFLX), ofloxacin (OFLX), levofloxacin (LVFX) and grepafloxacin (GPFX),

on L-carnitine transport mediated by OCTN2 in placental cell line BeWo cells. We found that all of the

fluoroquinolones inhibited L-carnitine transport, GPFX being the strongest inhibitor. We also found that

the inhibitory effects of LVFX and GPFX depended on their existence ratio of zwitterionic forms as, we

reported previously. Furthermore, we elucidated the LVFX transport mechanism in BeWo cells. LVFX was

transported actively by transporters. However, we found that LVFX transport was Na+-independent and

l-carnitine had no inhibitory effect on LVFX transport, suggesting that LVFX acts as inhibitor of OCTN2,

not as a substrate for OCTN2.”

http://www.ncbi.nlm.nih.gov/pubmed/3398700 Systemic acetyl-L-carnitine elevates nigral levels of

glutathione and GABA

References 13 website: JMR, http://fluoroquinolonethyroid.com