The effects of N-[1-(2-benzo[b]thiophenyl)cyclohexyl]- piperidine (BTCP), a phencyclidine derivative that acts as a potent dopamine reuptake inhibitor, were examined on cocaine self-administration in rats. The effects of BTCP (0, 4, 8, 16, and 32 mg/kg, i.p.) on cocaine self-administration were tested against cocaine doses on both the ascending (0.0625 mg/infusion) and descending (0.25 mg/infusion) limb of the dose-response function. BTCP decreased self-administration of the 0.25-mg cocaine dose in a dose-dependent manner. A 16-mg/kg dose of BTCP that strongly suppressed self-administration of the 0.25-mg cocaine dose increased the intake at the 0.0625-mg dose of cocaine. Moreover, cocaine and BTCP pretreatments produced similar patterns of decreases in self-administration of cocaine on the descending limb of the dose-response function. The results suggest that BTCP has cocaine-like actions and produces a leftward shift of the dose-response curve for cocaine self-administration, indicating that the phencyclidine analog may substitute under certain conditions for the reinforcing effects of cocaine in self-administering rats.