5-Hydroxytryptamine M-receptor antagonism in the hypothalamus facilitates gastric emptying in the guinea-pig.
The injection of 5-hydroxytryptamine (5-HT) and 2-methyl-5-HT into the perifornical area of the hypothalamus of the guinea-pig reduced the emptying of barium sulphate spheroids from the stomach. In contrast, the injection of the 5-HT M-receptor antagonist ICS 205-930 into the same area of the hypothalamus enhanced gastric emptying and attenuated the inhibitory effect of 5-HT. Similar injections of methysergide and ritanserin were without effect. It is concluded that an endogenous hypothalamic 5-HT system may inhibit gastric emptying through a 5-HT M-receptor mechanism which may afford a site of action for 5-HT agonist and antagonist drugs to modify gastric emptying.
D000818:Animals; D005746:Gastric Emptying / Q000187:drug effects*; D006168:Guinea Pigs; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects*; D016713:Ritanserin; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D000077526:Tropisetron
D007211:Indoles; D010880:Piperidines; D011985:Receptors, Serotonin; D016713:Ritanserin; D012701:Serotonin; D000077526:Tropisetron; C045918:2-methyl-5-HT; D008784:Methysergide