A three-choice discrimination procedure dissociates the discriminative stimulus effects of d-amphetamine and (±)-MDMA in rats.
Experimental and Clinical Psychopharmacology January 1, 2000 DOI: 10.1037//1064-1297.8.3.415
Summary
MDMA shows unique effects, distinct from traditional stimulants like d-amphetamine. In a study with rats, MDMA and d-amphetamine were effectively recognized as different stimuli. Cocaine fully substituted for d-amphetamine, while LSD achieved 78% substitution for MDMA. Interestingly, the hallucinogen 2,5-dimethoxy-4-bromoamphetamine only partially matched MDMA's effects and disrupted response rates. Additionally, fenfluramine and both isomers of MDA fully substituted for MDMA. Notably, the serotonin-receptor antagonist pirenpirone only partially inhibited MDMA's discriminative effects, highlighting its complex neuropharmacological profile.
Abstract
(+/-)-3,4-Methylenedioxymethamphetamine (MDMA) produces subjective effects in humans that are similar to, but distinguishable from, those of psychostimulants. Drug discrimination studies in nonhumans have yielded inconsistent results regarding the similarities between MDMA and the psychomotor stimulant d-amphetamine. This study successfully used a 3-choice operant procedure to establish MDMA and d-amphetamine as discriminative stimuli in rats. Cocaine produced complete substitution for d-amphetamine, and LSD produced dose-dependent increases in MDMA-appropriate responding with nearly complete substitution (78%) for MDMA. The hallucinogen 2,5-dimethoxy-4-bromoamphetamine only partially substituted for MDMA and severely disrupted response rate. Fenfluramine and both isomers of 3,4-methylenedioxyamphetamine (MDA) all produced complete substitution for MDMA. The serotonin-receptor antagonist pirenpirone only partially blocked MDMA discrimination.