Behavioral and rewarding effects of methylone, an analog of MDMA in mice

Abstract

    Methylone, an analog of 3,4-methylenedioxymethamphetamine (MDMA) is a narcotic drug which is forbidden due to its abusability. However, a detailed behavioral toxicity and rewarding effect of methylone has not yet been reported to this date. The aim of this study is to evaluate the toxicity and addictive effects of methylone. In order to detect the stimulant effect to central nervous system, a mouse behavioral toxicity test and a conditioned place preference (CPP) test were conducted by administering mehtylone, MDMA and methamphetamine (MAP). An immunohistochemical study was also performed to analyze ΔFosB, which is known to accumulate in the nucleus accumbens after chronic administration of the drugs of abuse. For determining the expression levels of ΔfosB mRNA in striatum, quantitative PCR analysis was also conducted by acute administration of methylone. Significant differences appeared in mice that were administered with 50 mg/kg and above of methylone. Methylone causes a similar qualitative behavioral effect as MAP, however not the same stereotyped behavior as MDMA. According to the result from CPP test, methylone of 2.5 mg/kg and above had shown a rewarding action. Chronic administration of methylone causes significant ΔFosB accumulation in the neurons of nucleus accumbens. Methylone and MDMA significantly induce ΔfosB mRNA in striatum. It is therefore suggested that methylone has psychoactive effects and can be considered as an addictive drug.