Involvement of dopamine in the aversive stimulus properties of cocaine in rats.
Previous studies of cocaine self-administration have demonstrated central dopaminergic involvement in cocaine's positive reinforcing properties. The present study reports the ability of pimozide, a dopamine receptor antagonist, to attenuate a conditioned taste aversion induced by repeated injections of cocaine. Rats placed on a daily water deprivation schedule were subsequently presented with a novel saccharin taste in their drinking fluid immediately followed by administration of four 9 mg/kg injections of cocaine spaced at 20 min intervals. These animals exhibited a reduction in saccharin intake on subsequent presentations. Animals pretreated with pimozide 90 min prior to the saccharin-cocaine pairings failed to show this reduction. In a second experiment using an identical procedure, repeated injections of lithium chloride were shown to induce a CTA both in pimozide-pretreated and control animals. The results of these two experiments are consistent with the notion that a functional relationship may exist between neurochemical mechanisms underlying both the aversive (CTA-inducing) and positive reinforcing properties of self-administered drugs such as cocaine.
Hunt
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T
Switzman
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L
Amit
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Z
D000818:Animals; D002712:Chlorides / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology*; D004326:Drinking / Q000187:drug effects; D004347:Drug Interactions; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D008297:Male; D010868:Pimozide / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012054:Reinforcement, Psychology
D002712:Chlorides; D010868:Pimozide; D008094:Lithium; D018021:Lithium Chloride; D003042:Cocaine; D004298:Dopamine