Dopamine and preparatory behavior: I. Effects of pimozide

The involvement of dopaminergic systems in appetitive and ingestive feeding behaviors was investigated in two experiments. Conditioned preparatory responses to a conditional stimulus (CS+) signaling delivery of a meal were attenuated in rats by doses of 0.4 and 0.6 mg/kg of the dopamine receptor antagonist pimozide. In contrast, animals responded in a normal fashion following the delivery of food. Similarly, in a separate study, the 20-min free-feeding intake of liquid diet by rats that had been deprived of food for 23 hr was unaffected by doses of pimozide as high as 0.6 mg/kg. These findings are consistent with the involvement of dopamine in the production of preparatory behaviors elicited by incentive stimuli.