title: 5-Hydroxytryptamine stimulates cyclic AMP formation in the tunica muscularis mucosae of the rat oesophagus via 5-HT4 receptors.
abstract: The nature of 5-HT4 receptor coupling in the tunica muscularis mucosae of the rat oesophagus has been studied. 5-HT and renzapride stimulated cyclic AMP formation concentration dependently, with -log EC50 values of 7.1 and 6.8, respectively. Renzapride, relative to 5-HT, acted as a partial agonist. Tropisetron (ICS 205 930) and a novel 5-HT4 antagonist, SDZ 205 557, inhibited 5-HT-induced cyclic AMP production competitively, with pA2 estimates of 6.7 and 7.7, respectively. These data are consistent with the hypothesis that 5-HT4 receptors mediate relaxation of the smooth muscle cells of the tunica muscularis mucosae of rat oesophagus via activation of adenylyl cyclase.
authors.affiliation: Institute of Pharmacology, Syntex Research, Palo Alto, CA 94304.
authors.forename: A P
authors.initials: AP
authors.lastname: Ford
authors.forename: G S
authors.initials: GS
authors.lastname: Baxter
authors.forename: R M
authors.initials: RM
authors.lastname: Eglen
authors.forename: D E
authors.initials: DE
authors.lastname: Clarke
mesh_terms: D000225:Adenine / Q000378:metabolism; D000818:Animals; D000242:Cyclic AMP / Q000096:biosynthesis*; D004947:Esophagus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*
chemical_list: D011985:Receptors, Serotonin; D012701:Serotonin; D000242:Cyclic AMP; D000225:Adenine