Enhancement of conditioned place preference response to cocaine in rats following subchronic administration of 3,4-methylenedioxymethamphetamine (MDMA)

Abstract

In this study, we measured conditioned place preference (CPP) responses to cocaine following subchronic administration of the recreationally abused drug (+/-)-3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") in male Sprague-Dawley rats. Animals were given either vehicle (1 ml/kg of distilled water, s.c.) or MDMA (20 mg/kg, s.c.) twice a day for 4 consecutive days. Two weeks later, CPP responses to cocaine (5, 10, or 20 mg/kg, i.p.) were measured. The MDMA-treated animals showed a significantly greater CPP response to cocaine than the vehicle-treated animals. Since conditioned place preference is believed to be a measure of appetitive behavior, these results suggest that MDMA abuse could lead to an increased vulnerability to the rewarding actions of cocaine and, hence, to increased vulnerability to cocaine addiction and dependence.

Effects of MDMA exposure on the conditioned place preference produced by other drugs of abuse

“…The present results show that MDMA pretreatment had no effect on undrugged contextual association. This is supported by earlier work showing no alterations in saline preference produced by MDMA in the CPP model (Schechter 1991;Horan et al 2000). Parallels may be drawn with other investigations of MDMA that have generally shown no changes in learning or memory (e.g.…”

“…In agreement with the current findings, prior exposure to MDMA (20 mg/kg SC every 12 h for 96 h) was found to have no effect upon the CPP produced by 1.5 mg/kg MDMA (Schechter 1991). Yet in contrast to the data reported here, multiple dose MDMA regimens have been shown to increase cocaine-induced CPP (Horan et al 2000;Fone et al 2002). Essentially, the use of an alternative MDMA regimen or CPP protocol may have yielded results that were more in keeping with the literature.…”

Long-term changes in social interaction and reward following repeated MDMA administration to adolescent rats without accompanying serotonergic neurotoxicity

“…Nonetheless, MDMA pre-treatment significantly enhanced the time that cocaine-treated rats spent in the drug paired compartment post-conditioning. This is consistent with a recent demonstration that MDMA enhanced the rewarding effect of cocaine in a similar conditioned place preference test (Horan et al 2000), but it is unlikely to be due to serotonergic depletion, as suggested by these workers.…”

Alterations in diurnal and nocturnal locomotor activity in rats treated with a monoamine-depleting regimen of methamphetamine or 3,4-methylenedioxymethamphetamine

“…Although Robinson and Camp (1987) report a more pronounced deficit in activity during the nocturnal cycle in d-amphetamine sensitized animals, a significant reduction in spontaneous locomotor activity occurred during the diurnal cycle as well. Consistent with these results, it has been demonstrated recently that the repeated administration of MA or MDMA produces properties of behavioral sensitization in rats (Kalivas et al 1998;Wallace et al 1999Wallace et al , 2001Horan et al 2000).…”