Mephedrone, compared with MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and 5-HT levels in nucleus accumbens of awake rats
Article first published online: 21 NOV 2011
© 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society
British Journal of Pharmacology
Volume 164, Issue 8, pages 1949–1958, December 2011
How to Cite
Kehr, J., Ichinose, F., Yoshitake, S., Goiny, M., Sievertsson, T., Nyberg, F. and Yoshitake, T. (2011), Mephedrone, compared with MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and 5-HT levels in nucleus accumbens of awake rats. British Journal of Pharmacology, 164: 1949–1958. doi: 10.1111/j.1476-5381.2011.01499.x
- Issue published online: 21 NOV 2011
- Article first published online: 21 NOV 2011
- Accepted manuscript online: 26 MAY 2011 06:49AM EST
- Received; 18 January 2011; Revised; 23 April 2011; Accepted; 8 May 2011
- legal highs;
BACKGROUND AND PURPOSE 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 5-HT in the nucleus accumbens of awake rats and compare these effects with 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.
KEY RESULTS Mephedrone (3 mg·kg−1 s.c.) and (+)-amphetamine (1 mg·kg−1 s.c.) caused rapid increases in extracellular DA levels of 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 t1/2 values for elimination rate of mephedrone, MDMA and amphetamine-induced increases in extracellular DA levels were 25, 303 and 51 min, the corresponding t1/2 values for 5-HT were 26, 48 and 84 min, respectively. Locomotor activity was increased most by amphetamine, whereas both mephedrone and MDMA showed about three times lower and shorter-lasting effects.
CONCLUSIONS AND IMPLICATIONS The neurochemical and functional properties of mephedrone resemble those of MDMA, but it also shows an amphetamine-like effect in that it evokes a rapid release and elimination of DA in the brain reward system, a feature that may contribute to its potent re-inforcing properties.