Anyone who’s ever seen an episode of Celebrity Rehab knows that addiction is a very complicated issue, and as scientists recently found out, even the molecular basis of addiction is no simple matter.
A group led by Paul Kenny at Scripps Florida studied cocaine use in rats that were allowed to dose themselves with the drug for 6 hours a day, and noted that they escalated their dosage daily — just like human addicts will often do.
The team focused on the relationship between the methyl CpG binding protein 2 (MeCP2) and addiction in the rats, and uncovered a novel interaction between MeCP2 and miR-212 where each member regulates the other. The two, it seems, fight it out for control of the brain-derived neurotrophic factor, BDNF, known to play a role in psychostimulant reward, and increase the rat’s’ desire for cocaine.
So, when levels of MeCP2 and BDNF in the dorsal striatum are increased the rats are more vulnerable to addiction; while knocking down MeCP2 by miR-212 reversed the desire to get high. Since there’’s no evidence of direct interaction between miR-212 and BDNF, it looks like the microRNA exerts its influence through MeCP2 itself.
The reserachers think that this MeCP2/miR-212 balancing act is a key focal point in further understanding the biology of addiction.
Get hooked on all the details at Nature Neuroscience, August 2010.