Effects of CP94253 (3.0, 5.6 and 10 mg/kg, s.c.) on cue-elicited reinstatement of extinguished cocaine-seeking behavior expressed as the mean number of active lever responses during a 1-hour test session + standard error of the mean (SEM). Baselines (white bars) represent mean responses during the extinction sessions preceding each test. Animals (n = 8–10/group) were pre-treated with vehicle (gray bars) 15 minutes prior to one test, and their assigned dose of CP94253 (black bars) 15 minutes before the other test, with order of presentation counterbalanced. Cues were available response-contingently during the test session on a fixed ratio 1 schedule. * Represents a difference from baseline (Newman– Keuls, P < 0.005), and + represents a difference from vehicle pre-treatment test day (Newman–Keuls, P < 0.001)