Original articleAcute behavioral effects of co-administration of mephedrone and MDMA in mice

•We first studied behavioral interaction between mephedrone and MDMA in mice.•Co-administration of mephedrone and MDMA led to antidepressive effects.•These drugs injected concomitantly improved consolidation of memory processes.•Co-administration of mephedrone and MDMA did not influence anxiety-like behaviors.

BackgroundAbuse of more than one psychoactive drug is becoming a global problem. Our experiments were designed to examine the effects of a concomitant administration of 3,4-methylenedioxy-methamphetamine (MDMA) and mephedrone on depression- and anxiety-like behaviors and cognitive processes in Swiss mice.MethodsIn order to investigate the drug interactions the forced swimming test (FST) - an animal model of depression, the passive avoidance (PA) test - a memory and learning paradigm, as well as the elevated plus maze (EPM) test - test for anxiety level were used.ResultsThe results revealed that a concomitant administration of non-effective doses of mephedrone (1 mg/kg) and MDMA (1 mg/kg) exerted marked antidepressive effects in the FST. Also a co-administration of mephedrone (2.5 mg/kg) and MDMA (1 mg/kg) displayed a pro-cognitive action in the PA paradigm. Furthermore, even though mephedrone and MDMA can, in general, exert some anxiogenic effects in mice, the concomitant administration of nonactive doses of both drugs (0.05 and 0.1 mg/kg, respectively) in the EPM test, did not show any synergistic effect in our study.ConclusionsThe effects of mephedrone and MDMA combination on mammalian organisms were attempted to be evaluated in our study and the results are described in the present report. These results may help explain the reasons for and consequences of a concomitant administration of psychoactive substances with regards to the central nervous system, while being possibly useful in the treatment of polydrug intoxication.