title: Autoinhibition and desensitization of serotonergic responses in guinea pig ileum.
abstract: The present study was undertaken to investigate the autoinhibition and desensitization of 5-hydroxytryptamine (5-HT) using another agonist MK-212 on guinea pig ileum. 5-HT and MK-212 produced dose dependent contractions of guinea pig ileum. The responses to MK-212 were reduced in the presence of 5-HT and vice versa. Neither 5-HT nor MK-212 produced any change in the responses to histamine, acetylcholine or KCl. Increase in Ca++ in bathing fluid reversed the desensitization produced by MK-212 or 5-HT. Our data suggest that 5-HT and MK-212 produce desensitization which is specific for serotonergic receptors and possibly involves Ca++ ions.
authors.affiliation: Department of Pharmacology, L. M. College of Pharmacy, Navrangpura, Ahmedabad.
authors.forename: N
authors.initials: N
authors.lastname: Chinmayee
authors.forename: D P
authors.initials: DP
authors.lastname: Joshi
authors.forename: A A
authors.initials: AA
authors.lastname: Mehta
authors.forename: R K
authors.initials: RK
authors.lastname: Goyal
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004351:Drug Resistance; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D011719:Pyrazines / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D011719:Pyrazines; D012701:Serotonin; C014896:6-chloro-2-(1-piperazinyl)pyrazine; D002118:Calcium