CHOLECYSTOKININ OCTAPEPTIDE DECREASES FOOD-INTAKE IN WHITE-CROWNED SPARROWS

White-crowned sparrows maintained on short days (9:15-h light-dark cyc le) were peripherally injected with 1.0, 4.0, and 16 mug/kg ip of chol ecystokinin 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 mug/kg was attenua ted by 100 mug/kg of the type-A CCK receptor antagonist MK-329 but not by 300 mug/kg of the type-B CCK receptor antagonist L 365,260, sugges ting that CCK-induced suppression of food intake in this species is me diated by a CCK-A receptor. Administration of both CCK-A and CCK-B rec eptor antagonists alone resulted in no change in meal size. These expe riments suggest that white-crowned sparrows, when weight stable, respo nd to CCK-8 in a manner comparable with several mammalian species.