Further investigation of the discriminative stimulus properties of MDA.

Rats trained to discriminate either (+)-amphetamine or (+/-)-MDA from saline in a two-lever drug discrimination task, were used to study the stimulus effects of MDA and its two optical isomers. Amphetamine-stimulus generalization occurred to S(+)-MDA, but not to its enantiomer R(-)-MDA. This, coupled with our earlier finding of DOM-stimulus generalization to R(-)-MDA but not to S(+)-MDA, suggests that the stimulus effects of S(+)-MDA are predominantly amphetamine-like while those of R(-)-MDA are more DOM-like. Thus, animals trained to discriminate racemic MDA from saline can apparently recognize members of both classes of agents.