Age differences in (±) 3,4‐methylenedioxymethamphetamine (MDMA)‐induced conditioned taste aversions and monoaminergic levels

Adolescent rats are less sensitive than adults to the aversive effects of MDMA, as measured by conditioned taste aversion. In the study, adolescent and adult Sprague-Dawley rats received subcutaneous injections of MDMA at doses of 0, 1.0, 1.8, or 3.2 mg/kg. Adolescents developed weaker taste aversions during acquisition and on a final two-bottle test. MDMA at these low doses did not consistently alter monoamine or metabolite levels in brain regions for either age group, though levels varied with age. The reduced sensitivity to MDMA's aversive effects in adolescents may increase their vulnerability to MDMA abuse.

Study at a glance

Abstract

Preclinical work indicates that adolescent rats appear more sensitive to the rewarding effects and less sensitive to the aversive effects of abused drugs. The present investigation utilized the conditioned taste aversion (CTA) design to measure the relative aversive effects of (±)3,4-methylenedioxymethamphetamine (MDMA; 0, 1.0, 1.8, or 3.2 mg/kg) in adolescent and adult Sprague-Dawley rats. After behavioral testing was complete, monoamine and associated metabolite levels in discrete brain regions were quantified using high-performance liquid chromatography coupled to electrochemical detection (HPLC-ECD) to determine if adolescent animals displayed a different neurochemical profile than did adult animals after being exposed to subcutaneous low doses of MDMA. Adolescent rats displayed less robust MDMA-induced taste aversions than adults during acquisition and on a final two-bottle aversion test. MDMA at these doses had no consistent effect on monoamine levels in either age group, although levels did vary with age. The relative insensitivity of adolescents to MDMA's aversive effects may engender an increased vulnerability to MDMA abuse in this specific population.