A comparison of the reinforcing efficacy of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") with cocaine in rhesus monkeys.
The purpose of the present study was to compare the reinforcing efficacy of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') to cocaine. Rhesus monkeys (n=4) responded under a within-session, exponentially increasing, progressive-ratio (PR) schedule of cocaine reinforcement. Breaking point (BP) for the PR schedule was defined as the final response requirement completed before 2 h had elapsed without an injection delivered. Saline and doses of cocaine (0.003-0.3 mg/kg/injection) and MDMA (0.01-0.56 mg/kg/injection) were substituted for the training dose of cocaine for at least five consecutive sessions. Both cocaine and MDMA functioned as reinforcers, but self-administration of MDMA occurred at fewer doses and a significantly lower peak BP was obtained for MDMA. These data demonstrate that MDMA functions as a reinforcer, although its reinforcing efficacy appears to be less than that of cocaine.
Lile
Joshua A
JA
Center for the Neurobiological Investigation of Drug Abuse, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
Ross
Jason T
JT
Nader
Michael A
MA
D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D006213:Hallucinogens / Q000494:pharmacology*; D008253:Macaca mulatta; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D012054:Reinforcement, Psychology; D012646:Self Administration
D000662:Amphetamines; D018765:Dopamine Uptake Inhibitors; D006213:Hallucinogens; D003042:Cocaine; D018817:N-Methyl-3,4-methylenedioxyamphetamine