The effects of MDMA preexposure on MDMA-induced taste aversions

Although changes in a drug's aversive effects may impact its abuse potential, little is known about factors that impact the aversive effects of MDMA. To that end, the present study used the conditioned taste aversion (CTA) preparation to assess how prior MDMA experience may affect the drug's aversive properties. In Experiment 1, a dose-response analysis of MDMA-induced taste aversions was conducted with Sprague-Dawley rats using three doses of MDMA (1.0, 1.8, 3.2 mg/kg) and vehicle. CTA's induced by MDMA were dose-dependent, with the greatest aversions obtained with 3.2 mg/kg MDMA. In Experiment 2, the effects of a prior MDMA history on MDMA-induced CTA's were examined. Rats preexposed to MDMA (1.8 mg/kg) displayed attenuated aversions, as compared to MDMA-naive rats conditioned with MDMA. Results are discussed in terms of pharmacological tolerance to the aversive properties of MDMA, which may contribute to increased abuse liability among subpopulations of MDMA users.