Behavioural analysis of the acute and chronic effects of MDMA treatment inthe rat

Rationale: A variety of animal models have shown MDMA (3,4-methylenedioxyme thamphetamine) to be a selective 5-HT neurotoxin, though little is known of the long-term behavioural effects of the pathophysiology. The widespread r ecreational use of MDMA thus raises concerns over the long-term functional sequelae in humans. Objective: This study was designed to explore both the acute- and post-treatment consequences of a 3-day neurotoxic exposure to MD MA in the rat, using a variety of behavioural paradigms. Methods: Following training to pretreatment performance criteria, animals were treated twice daily with ascending doses of MDMA (10, 15, 20 mg/kg) over 3 days. Body tem perature, locomotor activity, skilled paw-reaching ability and performance of the delayed non-match to place (DNMTP) procedure was assessed daily duri ng this period and on an intermittent schedule over the following 16 days. Finally, post mortem biochemical analyses of [H-3] citalopram binding and m onoamine levels were performed. Results: During the MDMA treatment period, an acute 5-HT-like syndrome was observed which showed evidence of tolerance . Once drug treatment ceased the syndrome abated completely. During the pos t-treatment phase, a selective, delay-dependent, deficit in DNMTP performan ce developed. Post-mortem analysis confirmed reductions in markers of 5-HT function, in cortex, hippocampus and striatum, Conclusions: These results c onfirm that acutely MDMA exposure elicits a classical 5-HT syndrome. In the long-term, exposure results in 5-HT neurotoxicity and a lasting cognitive impairment. These results have significant implications for the prediction that use of MDMA in humans could have deleterious long-term neuropsychologi cal/psychiatric consequences.