Kehr J, Ichinose F, Yoshitake S, Goiny M, Sievertsson T, Nyberg F, Yoshitake T.
“Mephedrone, compared to MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and serotonin levels in nucleus accumbens of awake rats”.
Br J Pharmacol. 2011 May 27.
The designer drug 1-(4-methylphenyl)-2-methylaminopropan-1-one (4-methylmethcathinone, mephedrone) is reported to possess psychostimulant, entactogenic and hallucinogenic effects. The purpose of this study was to examine the effects of acute administration of mephedrone on extracellular levels of dopamine (DA) and serotonin (5-HT) in the nucleus accumbens of awake rats and compare these effects to those induced by 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and amphetamine. Experimental approach: Microdialysis sampling was performed while simultaneously recording locomotor activity in rats and the monoamines were determined by HPLC with electrochemical detection.
RESULTS: Mephedrone (3 mg.kg(-1) s.c.) and (+)-amphetamine (1 mg.kg(-1) s.c.) caused rapid increases in extracellular DA levels to 496% and 412%, respectively, whereas MDMA (3 mg.kg(-1) s.c.) showed only a moderate effect (235%). The corresponding 5-HT levels increased to 941% (mephedrone) and 911% (MDMA), but only to 165% following amphetamine. The calculated half-lives (t(1/2) ) for elimination rate of mephedrone, MDMA and amphetamine-induced increases in extracellular DA levels were 25, 303 and 51 min, the corresponding t(1/2) values for 5-HT were 26, 48 and 84 min, respectively. Locomotor activation was highest for amphetamine, whereas both mephedrone and MDMA showed about three times lower and short-lasting effects. Conclusions and implications: Mephedrone resembles the neurochemical and functional properties of MDMA, but also shows amphetamine-like effect on rapid release and elimination of DA in the brain reward system, a feature that may contribute to its potent reinforcing properties.