Rewarding effects of 3,4-methylenedioxymethamphetamine ("Ecstasy") in dominant and subordinate OF-1 mice in the place preference conditioning paradigm.
G Rodriguez-Alarcón, J J Canales, A Salvador
Progress in neuro-psychopharmacology & biological psychiatry January 30, 2007 DOI: 10.1016/j.pnpbp.2006.08.018 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | OF-1 mice (dominant, subordinate, and non-confronted) |
| Intervention | MDMA |
| Dose | 2, 6, 10 mg/kg |
| Duration | 5 consecutive days of agonistic confrontation; drug conditioning with 4 injections on alternate days |
| Measures | conditioned place preference (CPP), c-Fos expression, serum testosterone and corticosterone levels |
| Topics | MDMA |
| Key findings | MDMA induced CPP at 2 and 6 mg/kg but not at 10 mg/kg in all groups, showing an inverted U-shaped dose-response. Social status did not alter MDMA's rewarding effects despite differences in testosterone and corticosterone levels. |
Abstract
We tested the ability of 3,4-methylenedioxymethamphetamine (MDMA) to induce conditioned place preference (CPP) in dominant and subordinate OF-1 mice subjected to cohabitation and repeated sessions of agonistic confrontation, as well as in non-confronted mice. We selected doses of MDMA (2, 6, 10 mg/kg) previously reported to induce CPP in mice and we measured expression of c-Fos evoked by the treatments in non-confronted mice. MDMA induced c-Fos protein in several corticolimbic regions involved in drug-induced reward. Mice were exposed to brief sessions of agonistic confrontation on 5 consecutive days. Determinations of circulating hormones and drug conditioning tests were carried out on completion of the encounters. The results of hormone assays indicated that dominant mice had higher serum concentrations of testosterone, but lower levels of corticosterone, than submissive mice. Post-conditioning tests after drug conditioning (4 injections of MDMA or saline on alternate days) showed that MDMA significantly produced CPP at doses of 2 and 6 mg/kg, but not at 10 mg/kg, an inverted U-shaped pattern of conditioning that was invariable in non-confronted, dominant and subordinate mice. These results demonstrate that the endocrine and behavioural correlates linked to social status and social stress in mice are not paralleled by significant changes in the rewarding efficacy of MDMA in the CPP paradigm under the specific conditions tested.