Dissociable effects of dopamine D1 and D2 receptors on compulsive ingestion and pivoting movements elicited by disinhibiting the ventral pallidum.

Previous studies have shown that infusion of a GABA receptor antagonist, such as bicuculline (bic), into the ventral (pallidum VP) of rats elicits vigorous ingestion in sated subjects and abnormal pivoting movements. Here, we assessed if the ingestive effects generalize to the lateral preoptic area (LPO) and tested both effects for modulation by dopamine receptor signaling. Groups of rats received injections of the dopamine D2 receptor antagonist, haloperidol (hal), the D1 antagonist, SCH-23390 (SCH), or vehicle (veh) followed by infusions of bic or veh into the VP or LPO. Ingestion effects were not observed following LPO bic infusions. Compulsive ingestion associated with VP activation was attenuated by hal, but not SCH. VP bic-elicited pivoting was attenuated by neither hal, nor SCH.