Rationale: It has been proposed that drugs that decrease cocaine self-administration or cocaine seeking by laboratory animals might be effective pharmacotherapies in the treatment of cocaine addiction. Previous studies have suggested that the dopamine uptake inhibitor, GBR 12909, might be such a candidate drug because it decreases cocaine self-administration. Other studies have shown that GBR 12909 elicits cocaine seeking, which might limit its utility as an anti-cocaine pharmacotherapy.
Objectives: The present study sought to compare the potency of GBR 12909 in decreasing cocaine self-administration and in eliciting cocaine seeking. These findings were compared to effects produced by the cocaine analog, WIN 35,428 and the non-specific monoamine uptake inhibitor, indatraline.
Methods: A within-session protocol was used to obtain the dose-effect relationship for cocaine self-administration in a single 5-6 h daily test session. Rats were pretreated with GBR 12909 (3.0-30.0 mg/kg), WIN 35,428 (0.1-1.0 mg/kg) or indatraline (0.03-1.00 mg/kg) 30 min prior to the test session.
Results: GBR 12909 and WIN 35,428 decreased responding maintained by intermediate and high doses of cocaine but indatraline failed to alter the cocaine dose-effect curve. Other groups of rats demonstrated that pretreatment with all three drugs reinstated extinguished cocaine-taking behavior, although indatraline was less efficacious than either GBR 12909 or WIN 35,428. Cocaine-produced drug seeking was enhanced by pretreatment with the highest doses of GBR 12909 and WIN 35,428 but was unaffected by pretreatment with indatraline. A low dose of GBR 12909 that decreased cocaine self-administration failed to produce drug seeking but equal doses of WIN 35,428 were required to decrease cocaine self-administration and to elicit drug seeking.
Conclusions: These data suggest a preferred profile of effects of GBR 12909 as an anti-cocaine pharmacotherapy. It is noted, however, that this drug might be expected to potentiate the ability of cocaine to elicit cocaine seeking following abstinence.