title: Do 5-HT4 receptors mediate the intestinal secretory response to 5-HT in rat in-vivo?
abstract: The involvement of the recently characterized 5-HT4 receptor in the actions of 5-hydroxytryptamine (5-HT) on jejunal, ileal and colonic electrogenic ion secretion was investigated in the rat in-vivo. 5-HT and the 5-HT1-, 5-HT2- and 5-HT4-receptor agonist 5-methoxytryptamine (5-MeOT), induced a rise in transintestinal PD in all regions of the gut. However, the 5-HT4-receptor agonists renzapride and cisapride had no effect. Furthermore, the 5-HT4-receptor antagonists SDZ 205-557 (2-diethylaminoethyl-[2-methoxy-4-amino-5-chloro] benzoate), tropisetron and SB 204070 ([1-butyl-4-piperidinylmethyl]-8-amino-7-chloro-1,4- benzodioxan-5-carboxylate hydrochloride) did not affect the secretory response to either 5-HT or 5-MeOT in the jejunum, but did cause a small inhibition in the ileum and colon. It is concluded that 5-HT4 receptors do not make a contribution to the electrically monitored 5-HT intestinal secretory response in the rat jejunum in-vivo, but may play a small role in the ileum and colon.
authors.affiliation: Department of Biomedical Science, University of Sheffield, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Franks
authors.forename: J
authors.initials: J
authors.lastname: Hardcastle
authors.forename: P T
authors.initials: PT
authors.lastname: Hardcastle
authors.forename: G J
authors.initials: GJ
authors.lastname: Sanger
mesh_terms: D010129:4-Aminobenzoic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008735:5-Methoxytryptamine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001549:Benzamides / Q000008:administration & dosage / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001643:Bridged Bicyclo Compounds / Q000008:administration & dosage / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic; D020117:Cisapride; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D004146:Dioxanes / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D000077526:Tropisetron; D062366:para-Aminobenzoates
chemical_list: D001549:Benzamides; D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004146:Dioxanes; D007211:Indoles; D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D062366:para-Aminobenzoates; C072790:2-methoxy-4-amino-5-chlorobenzoic acid 2-(diethylamino)ethyl ester; C084858:SB 204070A; D012701:Serotonin; D008735:5-Methoxytryptamine; D000077526:Tropisetron; C053006:renzapride; D010129:4-Aminobenzoic Acid; D020117:Cisapride