H

Purinergic andPyrimidinergic Signalling IMolecular, Nervous and UrogenitarySystem Function

Contributors

M.P. Abbracchio, M. Boarder, G. Burnstock, I.P. Chessell,G.P. Connolly, T.V. Dunwiddie, G.D. Housley, P.P.A. Humphrey,K.A. Jacobson, C. Kennedy, L.J.S. Knutsen, A. Lorenzen,S.A. Masino, A.D. Michel, IT. Neary, M. Salter, U. Schwabe,A. Sollevi, B. Sperlagh, E.S. Vizi, T.E. Webb, M. Williams,H. Zimmermann

EditorsM.P. Abbracchio and M. Williams

Springer

Contents

CHAPTER 1

Purinergic Neurotransmission: An Historical BackgroundM.P. ABBRACCHIO and M. WILLIAMS. With 1 Figure 1

A. Introduction 1B. Purine Availability 3C. PI and P2 Receptor Nomenclature 6

I. Adenosine (PI) Receptors 6D. P2 (ATP and UTP) Receptors 8

I. P2X Receptors 8II. P2Y Receptors 9

E. Mitochondrial Purinergic Receptors? 9F. Transgenic Models of PI and P2 Receptor Function 10G. Exponential Diversity? 10H. Conclusions 11References 11

Section I: Receptor Classification

CHAPTER 2

PI ReceptorsA. LORENZEN and U. SCHWABE. With 2 Figures 19

A. Introduction 19B. Localization and Function of PI Receptors 19

I. A, Adenosine Receptors 20II. A2A Adenosine Receptors 21

III. A2B Adenosine Receptors 22IV. A3 Adenosine Receptors 23

C. Structure of Adenosine Receptors 23D. Signal Transduction by Adenosine Receptors 26

XVI Contents

E. Adenosine Effects with Unknown Mechanisms andAdenosine Binding Proteins 32

List of Abbreviations 35References 35

CHAPTER 3

P2X ReceptorsI.P. CHESSELL, A.D. MICHEL and P.P.A. HUMPHREY. With 2 Figures . . . . 47

A. Introduction 47B. P2X Homomeric Subunits and Their Properties 48

I. P2X! 48II. P2X2 50

III. P2X3 50IV. P2X4 51V. P2X5 and P2X6 53

VI. P2X7 53C. Effects of Ions on Homomeric P2X Receptor Assemblies 56D. Receptor Binding Studies 57E. Heteropolymeric Combinations of P2X Subunits 57F. Conclusions 59References 59

CHAPTER 4

P2Y Receptors: Structure and FunctionM.R. BOARDER and T.E.WEBB. With 3 Figures 65

A. Introduction 65B. P2Y Receptors 66

I. G Protein-Coupled Receptors 66II. Diversity of P2Y Receptors: Cloning and Nomenclature . . . 67

III. Diversity of P2Y Receptors: Pharmacology 681. ATP and P2Yj Receptors 692. ATP and P2Y4 Receptors: Species Differences Between

Rat and Human 703. Agonists at P2Y Receptors 704. Antagonists at P2Y Receptors 71

C. Correlating Structure with Function 72I. Sequence Analysis 72

II. Structure and Function 751. Agonist/Receptor Interactions 752. Events Downstream of Receptor Activation 77

III. Post-Translational Modifications 771. Asparagine-Linked Glycosylation 772. Phosphorylation Sites 77

Contents XVII

IV. Non-G Protein Associations 771. Integrins 772. Na+/H+ Exchanger Regulatory Factor 77

D. Desensitisation 79E. Cell Signalling from P2Y Receptors 80

I. Coupling to Phospholipase C 80.II. Phospholipase C Independent Ca2+ Mobilisation 80

III. Regulation of Cyclic AMP 80IV. Regulation of Ion Channels 81

V. Stimulation of Tyrosine Kinases and Mitogen ActivatedProtein Kinases 81

References 82

CHAPTER 5

Purinergic Signalling in DevelopmentG. BURNSTOCK. With 8 Figures 89

A. Introduction 89B. Embryological Development 89

I. Frog Embryos 89II. Chick Embryos 91

1. Retina 912. Glial Cells 943. Skeletal Muscle 954. Cardiovascular System 955. Ganglia 976. Chondrocytes 98

III. Purinergic Receptors in Mammalian Embryos 981. Early Embryos 982. Central Nervous System (CNS) 1013. Cardiorespiratory System 1024. Skeletal Muscle 1035. Gastrointestinal Tract 1046. Skin 1047. Bone 1048. Lung 1059. Ectoenzymes 105

IV. Human Embryos 106C. Postnatal Development 106

I. Central Nervous System 106II. Cardiovascular System 109

1. Heart 1092. Vascular System 109

III. Airways I l l

XVIII Contents

IV. Gastrointestinal Tract I l lV. Vas Deferens 114

VI. Urinary Bladder 115VII. Other Organs 115

D. Summary 116References 116

CHAPTER 6

PI and P2 Purine and Pyrimidine Receptor LigandsK.A. JACOBSON and L.J.S. KNUTSEN. With 13 Figures 129

A. Introduction 129B. PI Receptor Ligands 130

I. PI Receptor Agonists 1301. Non-Selective Adenosine Receptor Agonists 130

a) NECA 130b) Metrifudil 130c) I-AB-MECA 133

2. Ai Receptor Agonists 133a) CPA 133b) R-PIA 133c) ADAC 134d) GR 79236 135e) SDZWAG994 135f) NNC-21-0136 136

3. A2A Receptor Agonists 136a) CGS 21680 136b) DPMA 137c) APEC 137d) HENECA 138

4. A3 Receptor Agonists 138a) IB-MECA 138b) Cl-IB-MECA 139c) NNC 21-0238 140

II. PI Receptor Antagonists 1401. A! Receptor Antagonists 140

a) DPCPX 140b) KFM 19 142c) BG 9719 142d) WRC-0571 142

2. A2A Receptor Antagonists 142a) SCH 58261 142b) CSC 143c) KW 6002 144

Contents XIX

d) ZM 241385 1443. A2B Receptor Antagonists 145

a) MRS 1754 1454. A3 Receptor Antagonists 145

a) L-249313 145b) MRS 1191 146c) MRS 1220 146

C. PI Receptor Modulators 147D. P2 Receptor Ligands 147

I. P2 Receptor Agonists 1491. 2-MethylthioATP and 2-MethylthioADP 1522. 2-(7-Cyanohexylthio)-ATP 1533. a,j3-MeATP 1534. #y-Methylene-D-ATP and /3,y-Methylene-L-ATP 1545. 3'-Benzylamino-3'-deoxyATP 1546. Adenosine 5'-O-(3-thiotriphosphate) (ATPyS) 1557. 2'- and 3'-O-(4-Benzoylbenzoyl)-ATP 2'- and

3'-O-(4-Benzoylbenzoyl)-ATP (BzATP) 1558. UTP and UDP 1569. UTPyS 156

10. HT-AMP and Other AMP-2-Thioethers 156II. P2 Receptor Antagonists 157

1. Suramin, NF023, and NF279 1572. Reactive Blue 2 1573. Pyridoxal Phosphate Derivatives (e.g., PPADS) 1604. Nucleotide Derivatives 1625. MRS 2179 and Other Bisphosphate Analogues 1626. KN-62 162

E. Conclusions 163References 163

Section II: Neurotransmission

CHAPTER 7

Regulation of Purine ReleaseB. SPERLAGH and E.S. VIZI. With 7 Figures 179

A. Introduction 179B. Releasable Purine Stores in Neuronal and

Non-Neuronal Cells 179I. Releasable ATP Stores 179

II. Releasable Adenosine Stores 181C. Release of Purines During Physiological Neuronal Activity

Simulated by Electrical or Chemical Depolarization 182

XX Contents

I. Release of Adenosine 182II. Release of ATP .183

1. Source of ATP Release in the Central NervousSystem (Presynaptic Origin) 184

2. Source of ATP Release in the Peripheral NervousSystem: Cascade Transmission (Postsynaptic Origin) . . . 190

D. Release of Purines by the Stimulation of Pre- orPost-Synaptic Receptors 194

E. Release of Purines by Pathological Stimuli 195I. Release of Purines by Hypoxia/Hypoglycemia/

Energy Deprivation 195II. Release of Purines by Inflammatory Stimuli 196

III. Release of Purines by Cellular Hypotonia 198IV. Purine Release by Cell Death Apoptosis 199

F. Concluding Remarks 199List of Abbreviations 200References 200

CHAPTER 8

Ecto-NucleotidasesH. ZIMMERMANN. With 2 Figures 209

A. Introduction 209B. The E-NTPDase Family 211

I. From Yeast to Vertebrates 211II. Vertebrate Isoforms 211

III. General Structural Properties 212IV. Catalytic Properties 214

1. Hydrolysis of Purine and Pyrimidine Nucleotides andCation Dependence 214

2. Km-Values 215V. Apyrase Conserved Regions and the /3- and y-Phosphate

Binding Motif 216VI. Inhibitors of Ecto-Nucleotidases 217

1. Search for Potency and Specificity 2172. Nucleotide Analogues 2183. Inhibitors of P2-Purinergic Receptors as

Ecto-Nucleotidase Inhibitors 2184. Others 219

VII. Wide and Overlapping Tissue Distribution 2191. Overall Distribution 2192. The Cardiovascular System 2203. The Nervous System 222

VIII. Regulation of Expression 223IX. Physiological and Pathological Implications 223

Contents XXI

1. Role in Thrombosis and Vascular Reperfusion 2232. Upregulation Following Global Forebrain Ischemia . . . . 2243. Alterations Following Plastic Changes in the

Nervous System 225C. The E-NPP Family 225

I. Three Types and their Structural Properties 225II. Catalytic Properties 226

1. Substrates and Inhibitors 2262. Cation Dependence and Km-Values 2273. The Catalytic Cycle 227

III. EF-Hand, Somatomedin B-Like Domain andRGD-Tripeptide 227

IV. Cell and Tissue Distribution 228V. Functional Roles in Physiology and Pathology 229

D. Extracellular Hydrolysis of Diadenosine Polyphosphates 230E. Ecto-5'-Nucleotidase 231F. Alkaline Phosphatase 232G. Ecto-Nucleoside Diphosphokinase and Ecto-Myokinase 233H. Extracellular Hydrolysis of NAD+ 233I. Ecto-Phosphorylation and Ecto-ADP Ribosylation 234J. Outlook 235References 236

CHAPTER 9

Role of Purines and Pyrimidines in the Central Nervous SystemS.A. MASINO and TV. DUNWIDDIE 251

A. Introduction 251B. PI Adenosine Receptors in Nervous Tissue 251

I. Physiological Responses 2521. Electrophysiological Actions 252

a) Modulation of Transmission 253b) Modulation of Plasticity 254c) Atypical A2A Receptors 254d) Interaction between Receptors 255e) Adenosine-Nitric Oxide Interactions 257

2. Behavioral Actions 257a) Pain 258b) Sleep/Arousal 258c) Thermoregulation 260d) Addiction 260e) Ethanol/Adenosine 261f) Interactions with Dopamine Systems 263

a) Role of Adenosine in Pathological Conditions... 263

XXII Contents

P) Locomotor Effects 2643. Functional Role(s) of Adenosine 264

a) Neuroprotection 265b) Epilepsy 267

II. Regulation of Extracellular Adenosine Concentrationsin Brain 2681. Adenosine Transporters 2682. Activity-Dependent Adenosine Release 2693. cAMP Efflux 2704. Extracellular Nucleotide Metabolism 2705. Adenosine Phosphorylation and Degradation 271

III. General Conclusions and New Directions 271C. P2 Nucleotide Receptors 272

I. P2 Receptor Distribution 272II. Physiological Responses to Application of ATP

and Other Nucleotides 273III. Synaptic Responses Mediated via ATP 275IV. Physiological Effects of Diadenosine Polyphosphates 276V. Responses Mediated by Pyrimidine Receptors 276

D. Conclusions 277References 277

CHAPTER 10

The Role of Purines in the Peripheral Nervous SystemC. KENNEDY. With 2-Figures 289

A. Introduction 289B. ATP and NA as Sympathetic Neurotransmitters 290

I. Storage in and Release of ATP Release fromSympathetic Nerves 290

II. Functional Effects of ATP Released fromSympathetic Nerves 292

1. Electrophysiological Effects 292a) Excitatory Junction Potentials 292b) P2X Receptors 293

2. Smooth Muscle Contraction 293a) Calcium Influx 293b) Contraction Profile 294

III. Termination of the Neurotransmitter Actionsof ATP and NA 294

IV. Issues to be Resolved 2941. Source of ATP Released During Sympathetic Nerve

Stimulation 2952. Transient or Maintained Release of ATP 295

Contents XXIII

C. ATP and ACh as Parasympathetic Neurotransmitters 296I. Functional Effects of ATP Released from

Parasympathetic Nerves 2961. Excitatory Junctional Potentials 2962. Smooth Muscle Contraction 2963. Calcium Channels Involved in Neurotransmitter

Release 2974. Termination of the Neurotransmitter Actions of

ATP and ACh 298II. Parasympathetic Neurotransmission in the Human Urinary

Bladder 2981. The Healthy Bladder 2982. Pathological Conditions 298

D. Concluding remarks n 299List of Abbreviations 299References 300

CHAPTER 11

Trophic Roles of Purines and PyrimidinesXT. NEARY and M.P. ABBRACCHIO. With 1 Figure 305

A. Introduction 305B. Effects on Muscle Cells 306

I. Effects on Vascular Smooth Muscle andEndothelial Cells 306

II. Effects on Myocardial Cells 308III. Effects on Skeletal Muscle Cells 309

C. Effects on Brain Cells 310I. Effects on Astrocytes 310

II. Effects on Microglia 312III. Effects on Other Glial Cells 313IV. Effects on Neuronal Cells 313

D. Effects on Immune Cells 314E. Effects on Secretory Cells 316

I. Effects on Exocrine Cells 3161. Salivary Cells 3162. Kidney Cells 316

II. Effects on Endocrine Cells 317F. Effects on Fibroblasts 318G. Effects on Bone Cells 319H. Effects on Reproduction 320I. Mechanisms 320J. Conclusions and Future Perspectives 326References 327

XXIV Contents

CHAPTER 12

Nucleoside and Nucleotide Transmission in Sensory SystemsG.D. HOUSLEY. With 2 Figures 339

A. Introduction 339I. Sensory Transmission Mediated by Nucleotides

and Nucleosides 339B. Olfactory and Gustatory Systems 341C. Visual System 341

I. Adenosine Actions on Retinal Neurotransmission 342II. Nucleosides and Nucleotides in Retinal Ontogeny 344

III. Nucleotide Signaling in the Retina 344IV. Nucleoside and Nucleotide Signaling in Ciliary Ganglion,

Ciliary Body, and Non-Pigmented Epithelium 3461. Regulation of Intraocular Pressure (IOP): Actions on

the Ciliary Body 3462. Neural Signaling in the Ciliary Body and Iris 348

V. Adenosine Regulation of Ocular Blood Flow:Protection During Ischemia and Hypoglycemia 349

VI. Nucleotide Signaling in the Lens 349VII. Trophic Actions of Adenosine 350

1. Vascular Endothelial Growth Factor 3502. Glucose Transport 350

D. Cochlear and Vestibular Systems 351I. Modulation of Hair Cell Sound Transduction and

Cochlear Micromechanics 3511. Hair Cell Membrane Conductance 3512. Nucleotide Regulation of Cellular Mechanics 3523. Regulation of the Electrochemical Gradient across the

Cochlear Partition 354II. Regulation of the K+ Flux into Endolymph 355

III. Putative Role in Auditory Neurotransmission 356IV. Localization of P2X and P2Y Receptor Expression:

A Role for Nucleotides in Cochlear Ontogeny 356V. Significance of Alternative Splicing of the P2X2 Receptor

mRNA in the Inner Ear 357VI. Adenosine Actions on Afferent Neurotransmission, Free ,

Radical Scavenging, Altered Cochlear Blood Flow, and HairCell Cation Channel Downregulation 358

E. Conclusion 359References 359

Contents XXV

CHAPTER 13

Roles of Purines in Nociception and PainM.W. SALTER and A. SOLLEVI. With 1 Figure 371

A. Introduction 371B. ATP and Adenosine in Somatosensory Neurotransmission 371

I. Release of ATP 3711. Release of ATP from Primary Afferent Neurons 3712. Co-Release of ATP with GABA from

Dorsal Horn Neurons 3723. Release of ATP from Other Cell Types in the

Periphery 372II. PI and P2 Purinergic Receptors 373

1. Purinergic Receptor Expression by Primary AfferentNeurons 373

2. Purinergic Receptor Expression by Dorsal HornNeurons 373

III. Actions of ATP and Adenosine 3741. Actions in Periphery 374

a) ATP 374b) Adenosine 375

2. Actions in the Dorsal Horn 376a) ATP 376b) Adenosine 377c) Extracellular Conversion of ATP to Adenosine

Mediates an Inhibitory Postsynaptic Responseto Low Threshold Primary Afferent Input 379

IV. Potential Therapeutic Implications from Basic Studies 3801. Targeting P2 Purinoceptors 3802. Targeting Adenosine Receptors 3823. Other Potential Therapeutic Implications 382

C. Clinical Aspects of Nociception/Antinociception 383I. General Considerations 383

II. Administration of Adenosine and AdenosineAnalogues 3841. Safety and Adverse Effects 384

a) IV Administration 384b) Intrathecal Administration 386c) Pharmacokinetics in CSF 387

2. Effects of Adenosine in Healthy Volunteers 3873. Effects of Adenosine in Acute Surgical Pain 389

a) Intraoperative Pain 389b) Postoperative Pain - Analgesic Requirements 389

4. Effects of Adenosine in Chronic NeuropathicPain Patients 390

XXVI Contents

5. Possible Sites of Action 391III. Adenosine as a Mediator of Analgesia Produced

by TENS 392D. Summary and Conclusions 393References 393

CHAPTER 14

Uridine and Pyrimidine Nucleotides in Cell FunctionG.P. CONNOLLY 403

A. Introduction 403B. Synthesis and Salvage of Pyrimidines 403C. Plasma and CSF Uridine 405D. Liver and Kidney Pathology 405E. Uridine Nucleotides and Cystic Fibrosis 406F. Pyrimidines and Reproductive Function 408G. Cancer and Antiviral Therapy 408H. Peripheral Nervous System Modulation 409I. CNS Modulation 410

I. Clinical Studies 411II. Animal Studies 412

1. Neuropeptide Interactions 4122. Dopamine Interactions 4123. Anticonvulsant and Anxiolytic Effects 4154. Sleep and Thermoregulation 4155. Additional Actions of Uridine and its Derivatives 416

References 417

CHAPTER 15

Purinergic Signalling in Lower Urinary TractG. BURNSTOCK. With 21 Figures 423

A. Introduction 423B. Parasympathetic Purinergic Cotransmission 426

I. Parallel Block of Responses to ATP and NANC NerveStimulation 428

II. Purinergic Excitatory Junction Potentials in the Bladder . . . 430III. Purinergic/Cholinergic Cotransmission 431IV. Extracellular Calcium, Calcium Channel Blockers and

Potassium Channel Openers 434V. Involvement of Prostaglandins in Purinergic

Transmission 436

Contents XXVII

VI. Ectoenzymatic Breakdown of ATP 437VII. In Vitro and In Vivo Studies 439

C. Receptors to Purines and Pyrimidines 442I. P2X Receptors Mediating Contraction of the Bladder 442

1. Agonist Potencies 4422. Localisation of P2X Receptors 4433. Structure-Activity Studies 446

II. P2Y Receptors Mediating Relaxation of the Bladder 447III. PI Receptors Mediating Relaxation and Contraction

of the Bladder 450D. Sympathetic Cotransmission 450E. Intramural Bladder Neurones and Pelvic Ganglia 452F. Neuromodulation in the Bladder 456G. Afferent Pathways in Bladder and Purinergic

Mechanosensory Transduction 458I. Evidence for a Suburothelial Sensory Nerve Plexus with

P2X3 Receptors 459II. Afferent Nerve Activity During Bladder Distension and

Evidence of Involvement of Purines 460III. Evidence for ATP Release from Urothelial Cells During

Distension 462IV. Evidence for Purinergic Involvement in

Bladder Nociception 463H. Perinatal Development of Purinergic Signalling in Urinary

Bladder 465I. Urethra 467J. Ureter 469K. Plasticity of Purinergic Signalling in Bladder, Urethra

and Ureter 470I. Changes Occurring During Pregnancy or Hormone

Therapies 470II. Changes Due to Selective Denervation 472

III. Bladder Grafts 474IV. Hibernation 474

L. Purinergic Signalling in the Human Bladder in Healthand Disease 474

I. Healthy Bladder 474II. Bladder Outflow Obstruction: Unstable, Hypertrophic

Bladders 478III. Neurogenic Hyperreflexive Bladder 479IV. Multiple Sclerosis (MS) 481V. Post-Irradiation Bladder Dysfunction 482

VI. Ischaemic Bladder 482VII. Chronic Alcohol Consumption and Bladder Function 482

VIII. Vitamin E Deficiency 483

XXVIII Contents

IX. Interstitial Cystitis , 483X. Diabetes 485

M. Concluding Comments 487References 488

Subject Index 517