MDMA ELICITS BEHAVIORAL AND NEUROCHEMICAL SENSITIZATION IN RATS

Rats were treated with repeated injections of saline or one of two dos es of (+/-)3,4-methylenedioxymethamphetamine (MDMA; 5 or 20 mg/kg, SC) . Rats pretreated with either of the two repeated MDMA treatment regim ens demonstrated an augmented increase in motor activity to an injecti on of MDMA made 12 days after the last repeated injection compared wit h either the first MDMA injection or MDA IA given to animals pretreate d with repeated saline. Furthermore, animals pretreated with the highe st dose of repeated MDMA revealed a greater behavioral response to coc aine (15 mg/kg, IP). Microdialysis was conducted in the nucleus accumb ens and the capacity of MDMA (5 mg/kg, SC) to elevate extracellular do pamine content was augmented in mts pretreated with repeated MDMA comp ared with the animals pretreated with repeated saline. These data reve al repeated MDMA administration produces behavioral sensitization and enhanced dopamine transmission in the nucleus accumbens of rats. (C) 1 998 American College of Neuropsychopharmacology. Published by Elsevier Science Inc.