Buspirone fails to affect the discriminative stimulus effects of cocaine.
Rats were trained to discriminate 4.0 mg/kg cocaine from saline in a two-lever, food-reinforced drug discrimination paradigm. Cocaine (0.5-8.0 mg/kg, IP) produced a dose-related increase in cocaine-appropriate responding, with the training dose of 4.0 mg/kg being the lowest dose that met criterion (> 90% cocaine-appropriate responding over the entire session) for substitution. Pretreatment with buspirone (2.0-16 mg/kg, IP) did not attenuate the discriminative stimulus properties of 4.0 mg/kg cocaine at doses up to those that caused complete suppression of responding (16 mg/kg, IP). In contrast, combinations of 0.12 mg/kg haloperidol with 4.0 mg/kg cocaine decreased cocaine-appropriate responding from 100 to 65% while suppressing response rate to 50% of the response rate seen with the 4.0-mg/kg dose of cocaine alone. Thus, behaviorally active doses of buspirone failed to attenuate the discriminative stimulus effects of cocaine in a sensitive behavioral paradigm.
Rapoza
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Drug Abuse Research Center, Pritzker School of Medicine, University of Chicago, IL 60637.
D000818:Animals; D002065:Buspirone / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology*; D004193:Discrimination Learning; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D003042:Cocaine; D006220:Haloperidol; D002065:Buspirone