Cocaine self-administration in monkeys: effects on the acquisition and performance of response sequences

A three-component multiple schedule of intravenous cocaine self-administrat ion (0.01-0.3 mg/kg), repeated acquisition and performance was used to exam ine the effects of self-administered cocaine on learning in rhesus monkeys. A 0.03 mg/kg infusion of cocaine maintained reliable self-administration w ithout markedly decreasing overall response rate or increasing the percenta ge of errors in the acquisition and performance components in which food wa s presented. When saline was substituted for 0.03 mg/kg of cocaine, there w as little or no effect on responding in the acquisition or performance comp onents while the number of infusions and response rate in the self-administ ration component decreased. These effects occurred to a greater extent unde r a FR 90 schedule (Experiment 2) as compared to a FR 30 schedule (Experime nt 1) of cocaine self administration. Substitution of higher infusion doses of cocaine also decreased response rate and the number of infusions in the self-administration components, and substantially decreased responding in the acquisition components; decreases in overall accuracy of responding wer e evident when responding in this schedule component occurred. Taken togeth er, these data indicate that learning is generally more sensitive than perf ormance to the disruptive effects of self-administered cocaine. (C) 2000 El sevier Science Ireland Ltd. All rights reserved.