A possible interaction between serotonin and cholecystokinin-8 in the ileo-colonic motor responses to feeding in rats.
The effects of cholecystokinin (CCK)-A, CCK-B, and 5-hydroxytryptamine-2 (5-HT2) receptor antagonists on the postprandial myoelectric activity of the ileum and the proximal and distal colon in rats were studied. After L364,718, a CCK-A receptor antagonist, or ritanserin, 5-HT2 receptor antagonist, the duration of the ileal postprandial motor pattern was reduced by 60%. In contrast, L365,260, a CCK-B receptor antagonist, had no effect. In the distal colon, the postprandial response was inhibited by CCK-A, CCK-B, and 5-HT2 receptor antagonists, whereas they were inactive in the proximal colon. CCK-8 administered at the end of the meal suppressed the inhibitory effect of ritanserin on the ileum and the distal colon. These results suggest that, in rats, CCK-8 is involved in the control of the ileal motor response to feeding through CCK-A receptors and in that of the distal colon through both CCK-A and CCK-B receptors. Serotonin seems to play a role in CCK-8 control through 5-HT2 receptors.
Benouali-Pellissier
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S
Applied Physiology and Pharmacology Laboratory (and INSERM U45), University of Savoie, Chambéry, France.
Roger
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T
Roche
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M
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002766:Cholecystokinin / Q000037:antagonists & inhibitors; D003106:Colon / Q000502:physiology*; D020109:Devazepide; D004435:Eating / Q000502:physiology*; D005769:Gastrointestinal Motility / Q000502:physiology*; D007082:Ileum / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists; D012844:Sincalide / Q000502:physiology*
D001570:Benzodiazepinones; D011949:Receptors, Cholecystokinin; D012702:Serotonin Antagonists; D016713:Ritanserin; D012701:Serotonin; D002766:Cholecystokinin; D020109:Devazepide; D012844:Sincalide