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.
|Number of pages||6|
|Journal||Drug and Alcohol Dependence|
|State||Published - May 9 2005|
Bibliographical noteFunding Information:
This research was supported by National Institute on Drug Abuse research grants DA-06634 (MAN) and DA-05934 (JAL). The authors thank D.R. Claytor, C.L. Hubbard and T.L. Moore for technical assistance and Drs. J.R. Tobin and R. Sherertz for consultation on catheter tract infection prevention.
- Drug abuse
- Reinforcing efficacy
- Rhesus monkey
ASJC Scopus subject areas
- Psychiatry and Mental health
- Pharmacology (medical)