TL neuro

July 6, 2011

Mephedrone Neurochemistry: MDMA-like?

Filed under: Cathinones — mtaffe @ 1:59 pm

ResearchBlogging.orgThe new paper by Kehr and colleagues reports neurochemical data for mephedrone (4-methylmethcathinone; 4MMC) in rats. As far as I can tell, these are the first in vivo experimental data to tell us anything about the actions of this newly popular recreational drug. (see DEA request for information on synthetic cathinones, for example.)

In this study, male Sprague-Dawley rats were prepared with microdialysis probes in the nucleus accumbens (“preferentially targeting the shell but also entering the core”) and then challenged with 1 or 3 mg/kg mephedrone, 1 mg/kg amphetamine, 3 mg/kg MDMA or vehicle.
Figure 2B from the paper (reproduced here) shows the main point which is that extracellular serotonin was increased by MDMA and mephedrone but not by amphetamine. The second point of interest is that dopamine (DA) levels were increased about twice as much by amphetamine or mephedrone than by MDMA. Unfortunately the authors did not appear to conduct full stats that could distinguish between the drugs. The provided analyses show only a significant difference from the vehicle condition. This may have been because N=4 is too low to provide sufficient power for many repeated comparisons, which is a shame.

The relative impact of amphetamine and MDMA on n. accumbens 5HT and DA overflow fits in very well with prior work, particularly from Baumann and Rothman of the NIDA Intramural Research Program. And this latter group showed very similar data on the effects of mephedrone at the recent CPDD meeting. So the initial neurochemistry fits in very well with the subjective reports from human user populations, particularly those that seem to say it feels like MDMA, not as good, but with a significantly higher risk for compulsive use. This latter might be associated with the DA effects (which the figure hints might be coming on even faster than for amphetamine, although the power issues preclude strong interpretations) or with the rapid resolution of the 5HT effect compared with MDMA (see figure above).
Literature Cited
Kehr, J., Ichinose, F., Yoshitake, S., Goiny, M., Sievertsson, T., Nyberg, F., & Yoshitake, T. (2011). Mephedrone, compared to MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and serotonin levels in nucleus accumbens of awake rats British Journal of Pharmacology DOI: 10.1111/j.1476-5381.2011.01499.x


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