S1796 Post-Natal Development of Cholinergic and Vipergic Regulation of Jejunal Permeability in the...
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AGA Abstracts Similarly, S100B mRNA, protein expression and secretion and iNOS expression and NO production were respectively assessed either in the presence, or absence of anti-RAGE antibody. Proliferation of human peripheral blood mononuclear cells (PBMC) isolated from healthy subjects was also checked by incubation with exogenous S100B. Results: In mucosal biopsies, exogenous S100B increased iNOS expression, NO production and lipid peroxidation through p38MAPkinase/Nuclear Factor-kappaB activation and via RAGE. Similarly, the addi- tion of LPS/IFN-γ significantly increased S100B mRNA, protein expression and secretion, accompanied with enhanced iNOS expression and NO production. In isolated myenteric ganglia, LPS/IFN-γ incubation resulted in a consistent EGC's activation (c-fos positive nuclei in S100B/GFAP positive cells), together with S100B up-regulation and increased NO produc- tion. Interestingly, exogenous S100B significantly increased PBMC proliferation and activation (increased NO and Tumor Necrosis Factor-alpha production) in a RAGE-dependent manner. Conclusions: EGC are activated by inflammatory stimuli and directly participate to NO production through S100B up-regulation. Increased levels of EGC-derived S100B are able to stimulate immune cells proliferation in a RAGE-dependent pathway. S1795 Differential Effect of the Endocannabinoid, Anandamide, On Survival of Enteric Ganglia and Neurons Yan Li, Sunila Mahavadi, Qing L. Zhang, Gracious R. Ross, Karnam S. Murthy, Li-Ya Qiao, John R. Grider In the central nervous system, cannabinoids have been reported to have variable effects, protecting neurons from toxic insult in some cases and causing apoptosis in others. The effect of endocannabinoids on survival of the enteric nervous system (ENS) is also variable although recent evidence suggests that endocannabinoids and their receptors are up-regulated and protective during inflammation. AIM: to examine the effect of anandamide on survival of cultured ganglia and neurons of the enteric nervous system. METHODS: Primary cultures of enteric ganglia were prepared from guinea pig intestine and grown in DMEM in the presence or absence of cytosine arabinoside (araC; 10 uM to reduce glial cells) and treated with anandamide (1 nM-10 uM) for 4 days. Some cultures were treated additionally with the CB1 receptor antagonist, AM251 (1 uM), or CB2 receptor antagonist, AM630 (1 uM), on day 3. Similar studies were done with an immortalized enteric neuronal cell line (IM- FEN). The effect of anandamide on neuronal survival was measured by counting cells immunostained with PGP9.5. The expression of CB1 and CB2 receptors was determined by western blot and immunohistochemistry. RESULTS: Anandamide had a biphasic effect on ganglionic survival, increasing survival at low concentrations (1 nM-0.1 uM) and decreasing survival at high concentrations (1-10 uM). Maximal survival (75% increase in number of ganglia surviving) occurred at 0.1 uM and the ED50 was 3 nM. The effect on survival was inhibited by AM251, but not AM630. Anandamide (1 nM-0.1 uM) had no effect on the number of neurons/ganglion in the absence of araC, but decreased the number of neurons/ ganglion by 20-25% in the presence of araC. This suggests that anandamide has differential effects, supporting neuronal survival in the presence of glial cells and inhibiting survival in the absence of glial cells. A direct inhibitory effect was confirmed in an enteric neuronal cell line where anandamide decreased neuronal survival in a concentration-dependent manner (12-46% decrease in survival at 1 nM-10 uM). This effect was partly reversed by AM251 and by AM630. Immunohistochemistry and western blot confirmed the presence of both CB1 and CB2 receptors in enteric neurons (primary cultures and IM-FEN) and glia (primary cultures). CONCLUSION: Anandamide promotes ganglionic and neuronal survival in the presence of glia but promotes neuron death in the absence of glia. This suggests a key role of glial cells in mediating the ability of endocannabinoids to promote neuronal survival. S1796 Post-Natal Development of Cholinergic and Vipergic Regulation of Jejunal Permeability in the Neonatal Piglet and Its Modulation By the Maternal Diet Francine de Quelen, Cecile Perrier, Gaelle Boudry The newborn intestine has the dual role of avoiding excess entry of harmful substances and pathogens but of allowing the passage a certain amount of material to ensure acquisition of oral tolerance. In adults, VIP and acetylcholine has been demonstrated as major mediators of the enteric nervous system regulation of intestinal barrier. However, nothing is known on nervous regulation of intestinal barrier in newborns. This study aimed at investigating cholinergic and VIPergic regulation of jejunal permeability in the neonatal piglet and its modulation by the maternal diet. Piglets were sacrificed at 0, 4, 7, 14, 21 and 28 days of life (n=6-7 per group). Jejunum was immediately mounted into Ussing chambers to measure permeability to FITC-dextran4000 (FD4) under basal conditions or after addition of 10-5M atropine, 10-5M hexamethonium, 10-2M carbachol, 10-4M betanechol or 10-6M VIP. In a second experiment, the same protocol was applied but piglets were born to and suckled sows receiving diets differing in fatty acid composition. Basal permeability to FD4 increased from birth to d14 and decreased thereafter (in ng/cm2/h, d0: 123±29a, d4: 280±39b, d7: 431±27c, d14: 599±116c, d21: 313±50b, d28: 321±59b; means with different letters are significantly different p<0.05). At d0, d4, d21 and d28, none of the cholinergic antagonist tested influenced FD4 fluxes. However, at d7 and d14, atropine reduced FD4 fluxes to levels similar to basal fluxes measured at d4, d21 and d28 (fluxes under atropine in ng/ cm2/h at d7: 263±117 and at d14: 291±100, p<0.05 compared to basal value); hexamethon- ium had no effect. Carbachol increased permeability at d21 and d28 but not before while betanechol had no effect at any of the ages studied. VIP reduced permeability from d4 and after. Supplementing the maternal diet with n-3 polyunsaturated fatty acid shifted this permeability increase to d21. In conclusion, VIPergic regulation of jejunal permeability seems to be effective as early as d4 in the piglet intestine. On the other hand, post-natal development of cholinergic regulation exhibits several phases: at d0 and d4, no cholinergic regulation was observed, then a cholinergic excitatory tonus keeps permeability high at d7 and 14 while afterwards, at d21 and d28, jejunal permeability was no more under such a cholinergic tonus and responded to cholinergic stimulation as observed in adults. This sequence of events seems to be alterable by the maternal diet. The consequences of this physiological increase of permeability induced by the enteric nervous system on the second week of life on maturation of the gut immune system warrants further investigations. A-272 AGA Abstracts S1797 Co-Culture of Enteric Neuronal Cells with Bioengineered Three-Dimensional Colonic Circular Smooth Muscle Constructs Robert R. Gilmont, Sita Somara, Shanthi Srinivasan, Shreya Raghavan, Khalil N. Bitar Background: We have previously shown that bioengineered GI smooth muscle rings mimic the physiological responses to contractile and relaxant agonists of In Vivo muscle tissue. However, to date, these rings have contained only smooth muscle cells. Recently, neuronal cell lines able to differentiate similar to primary enteric neurons have been developed. Objective: To produce bioengineered 3 D rings containing both circular smooth muscle cells (CSMC) and enteric neuronal cells. Methods: Bioengineered rings were manufactured from primary circular smooth muscle cells using a fibrin gel surrounding a circular mold. Cells from the neuronal cell line IM-FEN were expanded by incubation at 33oC in N2 medium containing FCS, INFγ and GDNF (growth medium). These cells were either suspended in a 0.4 mg/ml type I collagen solution and applied to a pre-formed muscle ring or allowed to gel within a 1.57 mm ID polyethylene tube containing the collagen solution before being extruded onto a CSMC ring. Following application of IM-FEN cells, the rings were incubated in neuronal differentiation medium at 39oC. Results: 1. Ring stability was unaffected in cultures where IN-FEN cells were applied to CSMC rings. 2. Noticeable elongation and branching of IM-FEM cells was observed in cells applied to rings by day three of incubation in differentiation medium. 3. No noticeable elongation and branching of IM-FEM cells was observed in extruded collagen incubated in growth medium. Summary: This is the first demonstration of the co-culture of neuronal cells with CSMC bioengineered rings. Application of IM-FEN cells to pre-formed CSMC 3 D constructs and subsequent culture at 39oC in neuronal differentiation medium had no apparent effect on CSMC viability and allowed the differentiation of IM-FEN cells into cells exhibiting neuronal cell morphological character- istics. Conclusion: The co-culture of CSMC and neuronal cells may represent an important step in developing functional colonic tissue for transplantation. The ability to deliver high numbers of neuronal cells to specific locations through the extrusion of cells in a biological matrix may prove to be of particular importance. Coupled with the ability to successfully implant bioengineered rings to acquire neo-vascularization, these studies may greatly advance colonic tissue replacement and transplantation. Supported by NIH/NIDDK 42876 S1798 Glucagon Like Peptide-2 Stimulates Growth and Differentiation of Adult Enteric Neurons Elaine de Heuvel, Laurie E. Wallace, Keith A. Sharkey, Catherine Ivory, David L. Sigalet Aim: Glucagon like peptide-2 (GLP-2) is an intestinal trophic factor which activates receptors on enteric neurons and myofibroblasts. We have shown previously that GLP-2 activates and is trophic to embryonic enteric neurons in culture. We hypothesize that GLP-2 will have similar trophic effects on adult enteric neurons in culture. Methods: Primary cultures of adult enteric neurons were grown from Sprague Dawley rats (n=23). The distal colon was removed; the submucosal plexus was dissected and dissociated with trypsin and collagenase, then plated onto poly-l-lysine coated coverslips in Neurobasal-A Media supplemented with 10% FBS, 0.5mM glutamine and 1% Pen-Strep. Cultures were treated with added GLP-2 (10-8M) or control media (changed every 3 days) for 7 days. Results: The cultured cells formed identifiable ganglia with interconnecting axons. Immunohistochemical staining with HuC/D and S-100 confirmed the cells were a mixture of neurons and glial cells. Staining demonstrated an increasing ratio of neurons to glial cells over time: At day 0: neuronal/glial cell ratio was 1:1, by day 21 GLP-2 treated: 14.9 ± 4.5 vs. control: 9.2 ± 3.6. GLP-2 induced specific differentiation of the cultured enteric neurons; the number of neurons was increased: GLP-2: 202 ± 110 vs. control: 100 ± 53% (increase in neuronal cell number over 21 days). The number of axons per ganglia increased: GLP-2: 5.2 ± 1.9 axons/ganglia vs. control: 2.6 ±0.9. GLP-2 treatment also promotes the growth of VIP expressing neurons (GLP-2: 84 ±11 vs. control: 58±13 %), NOS expressing neurons (GLP-2: 87± 5 vs. control: 64 ± 9%) and the number of neurons co-expressing VIP and NOS. The density of induced ganglia did not increase: GLP-2: 0.91 ± 0.05 vs. control: 0.97 ±-0.23 ganglia/mm2. (all comparisons p<0.001, all n values 23, done in duplicate) Conclusions: GLP-2 selectively increases the growth of adult primary enteric neurons in a culture system, increasing the growth of neurons as compared to glia, inducing a specific pattern of axonal growth from the ganglia, and increasing the number of neurons that express both VIP and NOS. These findings demonstrate the plasticity of the ENS in adult animals, and that GLP-2 can modulate neuronal differentiation within this system. Thus, GLP-2 may be a link between nutrient input and the phenotypic profile of the ENS; this may have implications for intestinal function, and response to injury. S1799 Modification By Endogenous Nitric Oxide of Contractile Responses to TRPA1 Activation, But Not to TRPV1 Activation, in Isolated Mouse Distal Colon Kimihito Tashima, Akihisa Sugimoto, Kenjiro Matsumoto, Syunji Horie BACKGROUND & AIM: TRPV1 and TRPA1 channels, which are members of the transient receptor potential (TRP) channels expressed in primary sensory neurons, are activated by the specific temperature. Recently, we have shown that TRPV1 and TRPA1 activation with capsaicin or allyl-isothiocyanate induces contraction in isolated mouse rectum and distal colon, respectively (Eur. J. Pharmacol. 576, 143-150, 2007, Gastroenterology, 134 (Suppl 1), A-159, 2008). However, the modification of contractile responses to capsaicin and allyl- isothiocyanate by endogenous nitric oxide (NO), which is a major inhibitory neurotransmitter in the enteric nervous system, remains to be fully elucidated. In the present study, we investigated whether endogenous NO interacts with TRPV1- or TRPA1-expressing neurons by measuring smooth muscle tension in isolated mouse rectum and distal colon. METHODS: The rectum and distal colon were surgically isolated from male ddY mice. The longitudinal change in smooth muscle tension was isotonically measured using Magnus apparatus. RESULTS: In the rectum and distal colon, the TRPV1 agonist capsaicin (3 μM) induced
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sSimilarly, S100B mRNA, protein expression and secretion and iNOS expression and NOproduction were respectively assessed either in the presence, or absence of anti-RAGEantibody. Proliferation of human peripheral blood mononuclear cells (PBMC) isolated fromhealthy subjects was also checked by incubation with exogenous S100B. Results: In mucosalbiopsies, exogenous S100B increased iNOS expression, NOproduction and lipid peroxidationthrough p38MAPkinase/Nuclear Factor-kappaB activation and via RAGE. Similarly, the addi-tion of LPS/IFN-γ significantly increased S100B mRNA, protein expression and secretion,accompanied with enhanced iNOS expression and NO production. In isolated myentericganglia, LPS/IFN-γ incubation resulted in a consistent EGC's activation (c-fos positive nucleiin S100B/GFAP positive cells), together with S100B up-regulation and increased NO produc-tion. Interestingly, exogenous S100B significantly increased PBMCproliferation and activation(increased NO and Tumor Necrosis Factor-alpha production) in a RAGE-dependent manner.Conclusions: EGC are activated by inflammatory stimuli and directly participate to NOproduction through S100B up-regulation. Increased levels of EGC-derived S100B are ableto stimulate immune cells proliferation in a RAGE-dependent pathway.
S1795
Differential Effect of the Endocannabinoid, Anandamide, On Survival ofEnteric Ganglia and NeuronsYan Li, Sunila Mahavadi, Qing L. Zhang, Gracious R. Ross, Karnam S. Murthy, Li-YaQiao, John R. Grider
In the central nervous system, cannabinoids have been reported to have variable effects,protecting neurons from toxic insult in some cases and causing apoptosis in others. Theeffect of endocannabinoids on survival of the enteric nervous system (ENS) is also variablealthough recent evidence suggests that endocannabinoids and their receptors are up-regulatedand protective during inflammation. AIM: to examine the effect of anandamide on survivalof cultured ganglia and neurons of the enteric nervous system. METHODS: Primary culturesof enteric ganglia were prepared from guinea pig intestine and grown in DMEM in thepresence or absence of cytosine arabinoside (araC; 10 uM to reduce glial cells) and treatedwith anandamide (1 nM-10 uM) for 4 days. Some cultures were treated additionally withthe CB1 receptor antagonist, AM251 (1 uM), or CB2 receptor antagonist, AM630 (1 uM),on day 3. Similar studies were done with an immortalized enteric neuronal cell line (IM-FEN). The effect of anandamide on neuronal survival was measured by counting cellsimmunostained with PGP9.5. The expression of CB1 and CB2 receptors was determinedby western blot and immunohistochemistry. RESULTS: Anandamide had a biphasic effect onganglionic survival, increasing survival at low concentrations (1 nM-0.1 uM) and decreasingsurvival at high concentrations (1-10 uM). Maximal survival (75% increase in number ofganglia surviving) occurred at 0.1 uM and the ED50 was 3 nM. The effect on survival wasinhibited by AM251, but not AM630. Anandamide (1 nM-0.1 uM) had no effect on thenumber of neurons/ganglion in the absence of araC, but decreased the number of neurons/ganglion by 20-25% in the presence of araC. This suggests that anandamide has differentialeffects, supporting neuronal survival in the presence of glial cells and inhibiting survival inthe absence of glial cells. A direct inhibitory effect was confirmed in an enteric neuronalcell line where anandamide decreased neuronal survival in a concentration-dependentmanner(12-46% decrease in survival at 1 nM-10 uM). This effect was partly reversed by AM251and by AM630. Immunohistochemistry and western blot confirmed the presence of bothCB1 and CB2 receptors in enteric neurons (primary cultures and IM-FEN) and glia (primarycultures). CONCLUSION: Anandamide promotes ganglionic and neuronal survival in thepresence of glia but promotes neuron death in the absence of glia. This suggests a key roleof glial cells in mediating the ability of endocannabinoids to promote neuronal survival.
S1796
Post-Natal Development of Cholinergic and Vipergic Regulation of JejunalPermeability in the Neonatal Piglet and Its Modulation By the Maternal DietFrancine de Quelen, Cecile Perrier, Gaelle Boudry
The newborn intestine has the dual role of avoiding excess entry of harmful substances andpathogens but of allowing the passage a certain amount of material to ensure acquisitionof oral tolerance. In adults, VIP and acetylcholine has been demonstrated as major mediatorsof the enteric nervous system regulation of intestinal barrier. However, nothing is knownon nervous regulation of intestinal barrier in newborns. This study aimed at investigatingcholinergic and VIPergic regulation of jejunal permeability in the neonatal piglet and itsmodulation by the maternal diet. Piglets were sacrificed at 0, 4, 7, 14, 21 and 28 days oflife (n=6-7 per group). Jejunum was immediately mounted into Ussing chambers to measurepermeability to FITC-dextran4000 (FD4) under basal conditions or after addition of 10-5Matropine, 10-5M hexamethonium, 10-2M carbachol, 10-4M betanechol or 10-6M VIP. In asecond experiment, the same protocol was applied but piglets were born to and suckledsows receiving diets differing in fatty acid composition. Basal permeability to FD4 increasedfrom birth to d14 and decreased thereafter (in ng/cm2/h, d0: 123±29a, d4: 280±39b, d7:431±27c, d14: 599±116c, d21: 313±50b, d28: 321±59b; means with different letters aresignificantly different p<0.05). At d0, d4, d21 and d28, none of the cholinergic antagonisttested influenced FD4 fluxes. However, at d7 and d14, atropine reduced FD4 fluxes tolevels similar to basal fluxes measured at d4, d21 and d28 (fluxes under atropine in ng/cm2/h at d7: 263±117 and at d14: 291±100, p<0.05 compared to basal value); hexamethon-ium had no effect. Carbachol increased permeability at d21 and d28 but not before whilebetanechol had no effect at any of the ages studied. VIP reduced permeability from d4 andafter. Supplementing the maternal diet with n-3 polyunsaturated fatty acid shifted thispermeability increase to d21. In conclusion, VIPergic regulation of jejunal permeabilityseems to be effective as early as d4 in the piglet intestine. On the other hand, post-nataldevelopment of cholinergic regulation exhibits several phases: at d0 and d4, no cholinergicregulation was observed, then a cholinergic excitatory tonus keeps permeability high at d7and 14 while afterwards, at d21 and d28, jejunal permeability was no more under such acholinergic tonus and responded to cholinergic stimulation as observed in adults. Thissequence of events seems to be alterable by the maternal diet. The consequences of thisphysiological increase of permeability induced by the enteric nervous system on the secondweek of life on maturation of the gut immune system warrants further investigations.
A-272AGA Abstracts
S1797
Co-Culture of Enteric Neuronal Cells with Bioengineered Three-DimensionalColonic Circular Smooth Muscle ConstructsRobert R. Gilmont, Sita Somara, Shanthi Srinivasan, Shreya Raghavan, Khalil N. Bitar
Background: We have previously shown that bioengineered GI smooth muscle rings mimicthe physiological responses to contractile and relaxant agonists of In Vivo muscle tissue.However, to date, these rings have contained only smooth muscle cells. Recently, neuronalcell lines able to differentiate similar to primary enteric neurons have been developed.Objective: To produce bioengineered 3 D rings containing both circular smooth musclecells (CSMC) and enteric neuronal cells. Methods: Bioengineered rings were manufacturedfrom primary circular smooth muscle cells using a fibrin gel surrounding a circular mold.Cells from the neuronal cell line IM-FENwere expanded by incubation at 33oC inN2mediumcontaining FCS, INFγ and GDNF (growth medium). These cells were either suspended ina 0.4 mg/ml type I collagen solution and applied to a pre-formed muscle ring or allowedto gel within a 1.57 mm ID polyethylene tube containing the collagen solution before beingextruded onto a CSMC ring. Following application of IM-FEN cells, the rings were incubatedin neuronal differentiation medium at 39oC. Results: 1. Ring stability was unaffected incultures where IN-FEN cells were applied to CSMC rings. 2. Noticeable elongation andbranching of IM-FEM cells was observed in cells applied to rings by day three of incubationin differentiation medium. 3. No noticeable elongation and branching of IM-FEM cells wasobserved in extruded collagen incubated in growth medium. Summary: This is the firstdemonstration of the co-culture of neuronal cells with CSMCbioengineered rings. Applicationof IM-FEN cells to pre-formed CSMC 3 D constructs and subsequent culture at 39oC inneuronal differentiation medium had no apparent effect on CSMC viability and allowed thedifferentiation of IM-FEN cells into cells exhibiting neuronal cell morphological character-istics. Conclusion: The co-culture of CSMC and neuronal cells may represent an importantstep in developing functional colonic tissue for transplantation. The ability to deliver highnumbers of neuronal cells to specific locations through the extrusion of cells in a biologicalmatrix may prove to be of particular importance. Coupled with the ability to successfullyimplant bioengineered rings to acquire neo-vascularization, these studies may greatly advancecolonic tissue replacement and transplantation. Supported by NIH/NIDDK 42876
S1798
Glucagon Like Peptide-2 Stimulates Growth and Differentiation of AdultEnteric NeuronsElaine de Heuvel, Laurie E. Wallace, Keith A. Sharkey, Catherine Ivory, David L. Sigalet
Aim: Glucagon like peptide-2 (GLP-2) is an intestinal trophic factor which activates receptorson enteric neurons and myofibroblasts. We have shown previously that GLP-2 activates andis trophic to embryonic enteric neurons in culture. We hypothesize that GLP-2 will havesimilar trophic effects on adult enteric neurons in culture. Methods: Primary cultures ofadult enteric neurons were grown from Sprague Dawley rats (n=23). The distal colon wasremoved; the submucosal plexus was dissected and dissociated with trypsin and collagenase,then plated onto poly-l-lysine coated coverslips in Neurobasal-A Media supplemented with10% FBS, 0.5mM glutamine and 1% Pen-Strep. Cultures were treated with added GLP-2(10-8M) or control media (changed every 3 days) for 7 days. Results: The cultured cellsformed identifiable ganglia with interconnecting axons. Immunohistochemical staining withHuC/D and S-100 confirmed the cells were a mixture of neurons and glial cells. Stainingdemonstrated an increasing ratio of neurons to glial cells over time: At day 0: neuronal/glialcell ratio was 1:1, by day 21 GLP-2 treated: 14.9 ± 4.5 vs. control: 9.2 ± 3.6. GLP-2 inducedspecific differentiation of the cultured enteric neurons; the number of neurons was increased:GLP-2: 202 ± 110 vs. control: 100 ± 53% (increase in neuronal cell number over 21 days).The number of axons per ganglia increased: GLP-2: 5.2 ± 1.9 axons/ganglia vs. control: 2.6±0.9. GLP-2 treatment also promotes the growth of VIP expressing neurons (GLP-2: 84 ±11vs. control: 58±13 %), NOS expressing neurons (GLP-2: 87± 5 vs. control: 64 ± 9%) andthe number of neurons co-expressing VIP and NOS. The density of induced ganglia did notincrease: GLP-2: 0.91 ± 0.05 vs. control: 0.97 ±-0.23 ganglia/mm2. (all comparisons p<0.001,all n values 23, done in duplicate) Conclusions: GLP-2 selectively increases the growth ofadult primary enteric neurons in a culture system, increasing the growth of neurons ascompared to glia, inducing a specific pattern of axonal growth from the ganglia, and increasingthe number of neurons that express both VIP and NOS. These findings demonstrate theplasticity of the ENS in adult animals, and that GLP-2 can modulate neuronal differentiationwithin this system. Thus, GLP-2 may be a link between nutrient input and the phenotypicprofile of the ENS; this may have implications for intestinal function, and response to injury.
S1799
Modification By Endogenous Nitric Oxide of Contractile Responses to TRPA1Activation, But Not to TRPV1 Activation, in Isolated Mouse Distal ColonKimihito Tashima, Akihisa Sugimoto, Kenjiro Matsumoto, Syunji Horie
BACKGROUND & AIM: TRPV1 and TRPA1 channels, which are members of the transientreceptor potential (TRP) channels expressed in primary sensory neurons, are activated bythe specific temperature. Recently, we have shown that TRPV1 and TRPA1 activation withcapsaicin or allyl-isothiocyanate induces contraction in isolated mouse rectum and distalcolon, respectively (Eur. J. Pharmacol. 576, 143-150, 2007, Gastroenterology, 134 (Suppl1), A-159, 2008). However, the modification of contractile responses to capsaicin and allyl-isothiocyanate by endogenous nitric oxide (NO), which is a major inhibitory neurotransmitterin the enteric nervous system, remains to be fully elucidated. In the present study, weinvestigated whether endogenous NO interacts with TRPV1- or TRPA1-expressing neuronsby measuring smooth muscle tension in isolated mouse rectum and distal colon. METHODS:The rectum and distal colon were surgically isolated from male ddY mice. The longitudinalchange in smooth muscle tension was isotonically measured using Magnus apparatus.RESULTS: In the rectum and distal colon, the TRPV1 agonist capsaicin (3 μM) induced
