SCH 23390-induced hypophagia is blocked by the selective CCK-A receptor antagonist devazepide, but not by the CCK-B/gastrin receptor antagonist L-365,260.

The selective dopamine D-1 receptor antagonist SCH 23390 (30 micrograms/kg, SC) significantly reduced palatable food consumption by nondeprived rats in a 30-min test period. Prior administration of the selective CCK-A receptor antagonist devazepide (MK 329; L-364,718) blocked the hypophagic effect of SCH 23390. In contrast, prior administration of the selective CCK-B/gastrin receptor antagonist L-365,260 had no effect. Devazepide did not antagonize a matched hypophagic effect produced by the dopamine D-2 receptor antagonist raclopride (0.1 mg/kg, SC). These data direct attention to possible dopamine-cholecystokinin interactions in relation to the control of ingestional responses, and, more specifically, indicate possible functional relationships between D-1 and CCK-A receptor mechanisms.