Effects of priming injections of MDMA and cocaine on reinstatement of MDMA- and cocaine-seeking in rats.
Exposure to self-administered drugs is sufficient to produce drug-seeking in animal models. In many cases priming injections of drugs that share discriminative stimulus properties with the self-administered drug also can lead to drug-seeking, suggesting that exposure might precipitate relapse. The present investigation examined the ability of MDMA or cocaine priming injections to reinstate extinguished drug-seeking in rats. Priming injections of cocaine (0-20.0 mg/kg) and MDMA (0.0-10.0 mg/kg) reinstated extinguished drug-taking for both the cocaine- and MDMA-trained rats. In a separate group of cocaine-trained rats that received repeated exposure to 10.0 mg/kg MDMA, the initial exposure to MDMA (10.0 mg/kg, i.p.) failed to reinstate extinguished responding but MDMA became an effective prime for reinstatement of extinguished cocaine-taking behavior with repeated exposure. Effects of MDMA in MDMA-trained rats was greater than the effect in cocaine-trained rats suggesting that extensive experience with MDMA self-administration might have sensitized rats to this effect. These findings show that extinguished MDMA self-administration, like self-administration of other drugs of abuse, can be reinstated by exposure to psychostimulants thereby precipitating relapse.
Schenk
Susan
S
Victoria University of Wellington, School of Psychology, Wellington, New Zealand. Susan.Schenk@vuw.ac.nz
Hely
Lincoln
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Gittings
David
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Lake
Barbara
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Daniela
Evangeline
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D000818:Animals; D016739:Behavior, Addictive / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003463:Cues; D004305:Dose-Response Relationship, Drug; D005108:Extinction, Psychological / Q000187:drug effects / Q000502:physiology; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D012646:Self Administration / Q000379:methods* / Q000523:psychology
D003042:Cocaine; D018817:N-Methyl-3,4-methylenedioxyamphetamine