The effect of MDA and MDMA ("Ecstasy") isomers in combination with pirenpirone on operant responding in mice.

The behaviorally disruptive effects of the optical isomers of 1-(3,4-methylenedioxyphenyl-2-aminopropane) (MDA) and its N-methyl derivative (MDMA) were evaluated in 27 mice trained to bar-press for a liquid food reinforcement. In addition, a second study was conducted in which mice were pretreated with either saline or the 5-HT-2 antagonist, pirenpirone, prior to the administration of either MDMA or MDA using the same behavioral procedure. The results indicated that the behaviorally disruptive effects produced only by R(-)-MDA, but not those of S(+)-MDA, R(-)-MDA, nor of S(+)-MDMA, were significantly attenuated by pirenpirone. These findings support previous research findings which indicate that this isomer may be producing its behaviorally disruptive effects via an action on 5-HT-2 receptors.