The effect of optical isomers of 3,4-methylenedioxymethamphetamine (MDMA) on stereotyped behavior in rats.

The relative potencies of S(+)-, R(-)-3,4-methylenedioxymethamphetamine (MDMA) and S(+)-methylene-dioxyamphetamine (MDA) in inducing stereotyped behavior were determined in comparison with p-chloroamphetamine. S(+)-MDMA was more potent than R(-)-MDMA in eliciting stereotyped behaviors such as sniffing, head-weaving, backpedalling and turning and wet-dog shakes. These results are consistent with the actions of the drug on release of neurotransmitters in which the S(+) enantiomer is more potent. The desmethyl derivative of (+)MDMA, (+)MDA, was more potent than (+)MDMA in eliciting stereotyped behaviors, and produced wet-dog shake behavior.