Fig. 3.
Effects of pretreatment with mCPP (veh, 0.1–0.3 mg/kg) alone or in combination with SB 242084 (veh, 0.03 mg/kg) on cocaine (Coc)-induced reinstatement in squirrel monkeys (n = 3). A, effects of mCPP pretreatment on reinstatement induced by several doses of cocaine priming infusions. ♢, responding on the last day of extinction sessions. ○, cocaine-induced reinstatement after pretreatment with the mCPP vehicle. Filled symbols, cocaine-induced reinstatement after pretreatment with mCPP. B, pretreatment with 0.03 mg/kg SB 242084 did not induce reinstatement alone, but antagonized the effects of mCPP. Data (mean ± S.E.M.) are expressed as the percentage of responding maintained during EDMax cocaine self-administration sessions. The dotted lines represent baseline self-administration rate (100%, A and B) and extinction criterion (20%, A). *, significant difference (p < 0.05) for a given data point compared with the reinstatement effect induced by EDPeak cocaine prime alone (B). Abscissae, dose of cocaine prime (A) or drug combination (B). Ordinates, normalized response rate.