A three-choice discrimination procedure dissociates the discriminative stimulus effects of d-amphetamine and (+/-)-MDMA in rats.
(+/-)-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.
Goodwin
A K
AK
Department of Psychology, Western Michigan University, Kalamazoo, Michigan 49008, USA.
Baker
L E
LE
D004290:DOM 2,5-Dimethoxy-4-Methylamphetamine / Q000494:pharmacology; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology*; D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D003463:Cues; D003913:Dextroamphetamine / Q000494:pharmacology*; D004192:Discrimination, Psychological / Q000187:drug effects*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005277:Fenfluramine / Q000494:pharmacology; D008238:Lysergic Acid Diethylamide / Q000494:pharmacology; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
D004290:DOM 2,5-Dimethoxy-4-Methylamphetamine; D018759:Adrenergic Uptake Inhibitors; D003042:Cocaine; D003913:Dextroamphetamine; D018765:Dopamine Uptake Inhibitors; D005277:Fenfluramine; D008238:Lysergic Acid Diethylamide; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors