Prevention of drug priming- and cue-induced reinstatement of MDMA-seeking behaviors by the CB1 cannabinoid receptor antagonist AM251

• MDMA has obvious addictive potential for reinstating drug-seeking behavior.
• Methamphetamine can be an effective stimulus for reinstating MDMA-seeking behaviors.
• The CB1 cannabinoid receptor antagonist AM251 markedly blocked the MDMA-seeking behaviors.
• Drugs that suppress the cannabinoid system via CB1 receptors are expected to treat MDMA dependence.

Background3,4-Methylenedioxymethamphetamine (MDMA), a methamphetamine (METH) derivative, exhibits METH-like actions at monoamine transporters and positive reinforcing effects in rodents and primates. The purposes of the present study were to determine whether cross-reinstatement would be observed between MDMA and METH and if the cannabinoid receptor, a receptor known to play critical roles in the brain reward system, could modulate MDMA craving.MethodsRats were trained to press a lever for intravenous MDMA (0.3 mg/infusion) or METH (0.02 mg/infusion) infusions under a fixed ratio 1 schedule paired with drug-associated cues (light and tone). Following drug self-administration acquisition training, rats underwent extinction training (an infusion of saline). Reinstatement tests were performed once the extinction criteria were achieved.ResultsIn MDMA-trained rats, the MDMA-priming injection (3.2 mg/kg, i.p.) or re-exposure to MDMA-associated cues reinstated MDMA-seeking behavior. Additionally, a priming injection of METH (1.0 mg/kg, i.p.) also reinstated MDMA-seeking behavior. In contrast, none of the MDMA doses reinstated METH-seeking behavior in the METH-trained rats. The CB1 cannabinoid receptor antagonist AM251 markedly attenuated the MDMA-seeking behaviors induced by MDMA-priming injection or re-exposure to MDMA-associated cues in a dose-dependent manner.ConclusionsThese findings show that MDMA has obvious addictive potential for reinstating drug-seeking behavior and that METH can be an effective stimulus for reinstating MDMA-seeking behaviors. Furthermore, based on the attenuating effect of AM251 in the reinstatement of MDMA-seeking behaviors, drugs that suppress CB1 receptors may be used in treatment of MDMA dependence.