MDMA as a discriminative stimulus: isomeric comparisons

Pharmacol Biochem Behav. 1987 May;27(1):41-4. doi: 10.1016/0091-3057(87)90474-6.


Using a two-lever, food-motivated discrimination procedure, eight male rats were trained to discriminate 1.5 mg/kg of racemic 3,4-methylenedioxymethamphetamine (MDMA) from its vehicle, distilled water. Once trained, the rats demonstrated a dose-related decrease in discriminative performance after administration of lower doses of MDMA (ED50 = 0.27 mg/kg). Racemic MDMA-stimulus generalization occurred with both isomers of MDMA with the ED50 of the (+) isomer calculated as 0.50 mg/kg and for the (-) isomer being 1.07. Time-course data indicate that racemic MDMA has a peak effect from 20-60 min post-injection with a declining effect from 120-240 min. This time-course closely resembles that observed by subjective reports in human abusers and, together with previous data, would indicate that the discriminative paradigm would be useful in investigations as to the neurochemical effects of MDMA.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3,4-Methylenedioxyamphetamine / analogs & derivatives
  • 3,4-Methylenedioxyamphetamine / pharmacology*
  • Amphetamines / pharmacology*
  • Animals
  • Conditioning, Operant / drug effects
  • Discrimination Learning / drug effects*
  • Male
  • N-Methyl-3,4-methylenedioxyamphetamine
  • Rats
  • Rats, Inbred Strains
  • Stereoisomerism
  • Time Factors


  • Amphetamines
  • 3,4-Methylenedioxyamphetamine
  • N-Methyl-3,4-methylenedioxyamphetamine