Abstract
1. 5-Hydroxytryptamine (5-HT) stimulated a biphasic increase in short-circuit current (SCC) in guinea-pig isolated ileal mucosa. The initial 'spike' response to 5-HT was inhibited by tetrodotoxin (0.3 microM). We have investigated the 5-HT receptor mechanism(s) controlling the second 'maintained' component of the response which remained after treatment with tetrodotoxin. 2. 5-HT stimulated concentration-related increases in SCC with an EC50 value of 5.4 microM. Isobutyl-methylxanthine (IBMX, 10 microM) produced a six fold leftward shift of this concentration-response curve, suggesting the involvement of a cyclic nucleotide(s) in these responses. 3. In the presence of IBMX, 5-HT stimulated reproducible increases in SCC with an EC50 value of 0.9 microM. The rank order of potency of indole agonists in these tests was 5-HT greater than or equal to 5-methoxytryptamine greater than 5-carboxamidotryptamine = alpha-methyl-5-HT much greater than 2-methyl-5-HT. 4. The substituted benzamides were partial agonists. Metoclopramide and cisapride produced approximately 20% of the 5-HT maximum, and renzapride and R,S-zacopride produced approximately 50% of the 5-HT maximum. Metoclopramide and cisapride inhibited the SCC responses to 5-HT with apparent pKB values of 4.8 and 7.0 respectively. 5. The SCC responses to 5-HT were not inhibited by antagonists selective for 5-HT1 (methysergide, methiothepin), 5-HT2 (ketanserin) or 5-HT3 (ondansetron, ICS205-930) receptors. 6. The SCC responses to 5-methoxytryptamine, 5-carboxamidotryptamine, alpha-methyl-5-HT and R,S-zacopride, but not 5-HT, were selectively inhibited by high concentrations of ICS205-930 with apparent pKB values of approximately 6.(ABSTRACT TRUNCATED AT 250 WORDS)
Full text
PDF





Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baird A. W., Cuthbert A. W. Neuronal involvement in type 1 hypersensitivity reactions in gut epithelia. Br J Pharmacol. 1987 Nov;92(3):647–655. doi: 10.1111/j.1476-5381.1987.tb11368.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Baxter G. S., Craig D. A., Clarke D. E. 5-Hydroxytryptamine4 receptors mediate relaxation of the rat oesophageal tunica muscularis mucosae. Naunyn Schmiedebergs Arch Pharmacol. 1991 May;343(5):439–446. doi: 10.1007/BF00169544. [DOI] [PubMed] [Google Scholar]
- Beubler E., Coupar I. M., Hardcastle J., Hardcastle P. T. Stimulatory effects of 5-hydroxytryptamine on fluid secretion and transmural potential difference in rat small intestine are mediated by different receptor subtypes. J Pharm Pharmacol. 1990 Jan;42(1):35–39. doi: 10.1111/j.2042-7158.1990.tb05345.x. [DOI] [PubMed] [Google Scholar]
- Bockaert J., Sebben M., Dumuis A. Pharmacological characterization of 5-hydroxytryptamine4(5-HT4) receptors positively coupled to adenylate cyclase in adult guinea pig hippocampal membranes: effect of substituted benzamide derivatives. Mol Pharmacol. 1990 Mar;37(3):408–411. [PubMed] [Google Scholar]
- Bradley P. B., Engel G., Feniuk W., Fozard J. R., Humphrey P. P., Middlemiss D. N., Mylecharane E. J., Richardson B. P., Saxena P. R. Proposals for the classification and nomenclature of functional receptors for 5-hydroxytryptamine. Neuropharmacology. 1986 Jun;25(6):563–576. doi: 10.1016/0028-3908(86)90207-8. [DOI] [PubMed] [Google Scholar]
- Bunce K. T., Spraggs C. F. Stimulation of electrogenic chloride secretion by prostaglandin E2 in guinea-pig isolated gastric mucosa. J Physiol. 1988 Jun;400:381–394. doi: 10.1113/jphysiol.1988.sp017126. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clarke D. E., Craig D. A., Fozard J. R. The 5-HT4 receptor: naughty, but nice. Trends Pharmacol Sci. 1989 Oct;10(10):385–386. doi: 10.1016/0165-6147(89)90177-6. [DOI] [PubMed] [Google Scholar]
- Cooke H. J., Carey H. V. Pharmacological analysis of 5-hydroxytryptamine actions on guinea-pig ileal mucosa. Eur J Pharmacol. 1985 May 20;111(3):329–337. doi: 10.1016/0014-2999(85)90639-9. [DOI] [PubMed] [Google Scholar]
- Costa M., Furness J. B., Cuello A. C., Verhofstad A. A., Steinbusch H. W., Elde R. P. Neurons with 5-hydroxytryptamine-like immunoreactivity in the enteric nervous system: their visualization and reactions to drug treatment. Neuroscience. 1982 Feb;7(2):351–363. doi: 10.1016/0306-4522(82)90272-x. [DOI] [PubMed] [Google Scholar]
- Dohi Y., Criscione L., Lüscher T. F. Renovascular hypertension impairs formation of endothelium-derived relaxing factors and sensitivity to endothelin-1 in resistance arteries. Br J Pharmacol. 1991 Oct;104(2):349–354. doi: 10.1111/j.1476-5381.1991.tb12434.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Donowitz M., Charney A. N., Heffernan J. M. Effect of serotonin treatment on intestinal transport in the rabbit. Am J Physiol. 1977 Jan;232(1):E85–E94. doi: 10.1152/ajpendo.1977.232.1.E85. [DOI] [PubMed] [Google Scholar]
- Dumuis A., Bouhelal R., Sebben M., Cory R., Bockaert J. A nonclassical 5-hydroxytryptamine receptor positively coupled with adenylate cyclase in the central nervous system. Mol Pharmacol. 1988 Dec;34(6):880–887. [PubMed] [Google Scholar]
- Dumuis A., Sebben M., Bockaert J. The gastrointestinal prokinetic benzamide derivatives are agonists at the non-classical 5-HT receptor (5-HT4) positively coupled to adenylate cyclase in neurons. Naunyn Schmiedebergs Arch Pharmacol. 1989 Oct;340(4):403–410. doi: 10.1007/BF00167041. [DOI] [PubMed] [Google Scholar]
- ERSPAMER V. Pharmacology of indole-alkylamines. Pharmacol Rev. 1954 Dec;6(4):425–487. [PubMed] [Google Scholar]
- Eglen R. M., Swank S. R., Walsh L. K., Whiting R. L. Characterization of 5-HT3 and 'atypical' 5-HT receptors mediating guinea-pig ileal contractions in vitro. Br J Pharmacol. 1990 Nov;101(3):513–520. doi: 10.1111/j.1476-5381.1990.tb14113.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Feniuk W., Humphrey P. P., Perren M. J., Watts A. D. A comparison of 5-hydroxytryptamine receptors mediating contraction in rabbit aorta and dog saphenous vein: evidence for different receptor types obtained by use of selective agonists and antagonists. Br J Pharmacol. 1985 Nov;86(3):697–704. doi: 10.1111/j.1476-5381.1985.tb08948.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Furness J. B., Costa M. Neurons with 5-hydroxytryptamine-like immunoreactivity in the enteric nervous system: their projections in the guinea-pig small intestine. Neuroscience. 1982 Feb;7(2):341–349. doi: 10.1016/0306-4522(82)90271-8. [DOI] [PubMed] [Google Scholar]
- Hendriks R., Bornstein J. C., Furness J. B. Evidence for two types of 5-hydroxytryptamine receptor on secretomotor neurons of the guinea-pig ileum. Naunyn Schmiedebergs Arch Pharmacol. 1989 Apr;339(4):409–414. doi: 10.1007/BF00736055. [DOI] [PubMed] [Google Scholar]
- Humphrey P. P. Peripheral 5-hydroxytryptamine receptors and their classification. Neuropharmacology. 1984 Dec;23(12B):1503–1510. doi: 10.1016/0028-3908(84)90094-7. [DOI] [PubMed] [Google Scholar]
- Nelson D. R., Thomas D. R. [3H]-BRL 43694 (Granisetron), a specific ligand for 5-HT3 binding sites in rat brain cortical membranes. Biochem Pharmacol. 1989 May 15;38(10):1693–1695. doi: 10.1016/0006-2952(89)90319-5. [DOI] [PubMed] [Google Scholar]
- Rang H. P. The kinetics of action of acetylcholine antagonists in smooth muscle. Proc R Soc Lond B Biol Sci. 1966 Apr 19;164(996):488–510. doi: 10.1098/rspb.1966.0045. [DOI] [PubMed] [Google Scholar]
- Reeves J. J., Bunce K. T., Humphrey P. P. Investigation into the 5-hydroxytryptamine receptor mediating smooth muscle relaxation in the rat oesophagus. Br J Pharmacol. 1991 May;103(1):1067–1072. doi: 10.1111/j.1476-5381.1991.tb12301.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zimmerman T. W., Binder H. J. Serotonin-induced alteration of colonic electrolyte transport in the rat. Gastroenterology. 1984 Feb;86(2):310–317. [PubMed] [Google Scholar]
