A Comparison of MDMA and Amphetamine in the Drug Discrimination Paradigm

Abstract

This study used the Drug Discrimination paradigm to assess the relative subjective experience of acutely administered 3,4-Methylenedioxymethamphetamine (MDMA) and d-amphetamine (AMPH). In this paradigm rats are required to respond on one lever if they have been given a specific drug (AMPH for one group of rats or MDMA for another group) vs an alternate lever if they have been administered saline prior to a session. Generalisation and substitution testing was used to establish the extent to which rats previously trained to discriminate saline vs MDMA responded to novel exposure of AMPH. Likewise, we examined the extent to which rats previously trained to discriminate saline vs AMPH responded to novel exposure to MDMA. Previous research [1, 2] has demonstrated that rats can learn to discriminate MDMA from amphetamine, thus it was expected that only partial, if any, generalisation would be observed when exposed to an untrained novel drug. In addition, we examined the effect of concurrent administration of the D1 antagonist SCH23390 had on discrimination performance in both groups.