A Comparison of Repeated MDMA- and AMPH-Produced Centre and Periphery Activity and the Underlying Neuroadaptations

The recreational use of 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy') is increasing in New Zealand. MDMA is a ring-substituted derivative of AMPH and, similar to AMPH, produces hyperactivity upon administration. However, the behavioural profile of hyperlocomotion produced by MDMA differs from that produced by AMPH, suggesting that different neural mechanisms underlie the behavioural response. The repeated administration of both MDMA and AMPH induces sensitised hyperactive responses that have recently been found to be different. In the present study, MDMA- and AMPH-induced centre and periphery hyperactivity were compared to investigate the neuroadaptations produced by repeated exposure to the two drugs. Rats were pre-treated with saline, MDMA, or AMPH and the acute response to MDMA, AMPH, or the D1 agonist, SKF-81297 was measured to determine whether cross-sensitisation was produced. Repeated administration of MDMA and AMPH produced similar behavioural profiles. However, cross-sensitisation between the two drugs was uni-directional, suggesting that the two produce different neuroadaptations. Repeated AMPH, but not MDMA, produced a sensitised response to the hyperlocomotor effects of SKF-81297, suggesting that D1 receptor mechanisms are one example of different neuroadaptations.