Cholecystokinin octapeptide decreases food intake in white-crowned sparrows.
White-crowned sparrows maintained on short days (9:15-h light-dark cycle) were peripherally injected with 1.0, 4.0, and 16 micrograms/kg ip of cholecystokinin octapeptide (CCK-8). Meal size over the subsequent 30 min was significantly depressed in a dose-dependent fashion. Water intake was not affected. The anorexic effect caused by 4.0 micrograms/kg was attenuated by 100 micrograms/kg of the type-A CCK receptor antagonist MK-329 but not by 300 micrograms/kg of the type-B CCK receptor antagonist L 365,260, suggesting that CCK-induced suppression of food intake in this species is mediated by a CCK-A receptor. Administration of both CCK-A and CCK-B receptor antagonists alone resulted in no change in meal size. These experiments suggest that white-crowned sparrows, when weight stable, respond to CCK-8 in a manner comparable with several mammalian species.
Department of Psychology, University of Washington, Seattle 98195.
R D
RD
Richardson
T
T
Boswell
S C
SC
Weatherford
J C
JC
Wingfield
S C
SC
Woods
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D001717:Birds / Q000502:physiology*; D002766:Cholecystokinin / Q000037:antagonists & inhibitors; D020109:Devazepide; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D010671:Phenylurea Compounds; D012844:Sincalide / Q000494:pharmacology*
D001570:Benzodiazepinones; D010671:Phenylurea Compounds; C058121:L 365260; D002766:Cholecystokinin; D020109:Devazepide; D012844:Sincalide