BTCP is a potent reinforcer in rats: comparison of behavior maintained on fixed- and progressive-ratio schedules.

N-[1-(2-benzo[b]thiophenyl)cyclohexyl]piperidine (BTCP) is a phencyclidine (PCP) derivative that acts as a potent dopamine (DA) reuptake inhibitor. Earlier studies have shown that BTCP can substitute for the reinforcing effects of cocaine. Therefore, the aim of the study was to further characterize the reinforcing effects of BTCP. The reinforcing actions of BTCP were compared to those of cocaine at equimolar concentrations in drug-naïve rats. Two groups of animals were implanted with jugular catheters and trained to intravenously self-administer BTCP or cocaine (0.25 mg/infusion) on a fixed-ratio five schedule (FR 5) of reinforcement. Both BTCP and cocaine produced comparable inverted U-shaped dose-effect curves on this schedule over doses of 0.03, 0.06, 0.125, and 0.25 mg/infusion. Two doses (0.125 and 0.25 mg/infusion) that produced reliable self-administration in all the animals for cocaine and BTCP were then tested on a progressive-ratio schedule. At each dose, BTCP supported higher breaking points (BPs) than cocaine. The results demonstrate that rats readily acquire responding maintained by BTCP and suggest that BTCP may have greater reinforcing effects than cocaine at equimolar concentrations.