In this study the effects of cholecystokinin (CCK) microinjections into the rostral or caudal nucleus accumbens (Acc) on locomotor activation derived from systemic amphetamine treatment were examined. It was found that CCK microinjections into the rostral Acc attenuated and CCK microinjections into the caudal Acc potentiated amphetamine-induced locomotor activity. Results indicate that rostral Acc CCK microinjections have dopamine antagonistlike effects and caudal Acc CCK microinjections have dopamine agonistlike effects on amphetamine-induced locomotor activity. The relevance of the present findings to previous results regarding CCK-dopamine interactions is discussed.