[Epigenetics and drug addiction: a focus on MeCP2 and on histone acetylation]

Chronic drug exposure alters gene expression in the brain, which is believed to underlie compulsive drug seeking and drug taking behavior. Recent evidence shows that drug-induced long-term neuroadaptations in the brain are mediated in part by epigenetic mechanisms. By remodeling chromatin, this type of regulation contributes to drug-induced synaptic plasticity that translates into behavioral modifications. How drug-induced alterations in DNA methylation regulate gene expression is reviewed here, with a focus on MeCP2, a protein binding methylated DNA. The importance of histone modifications, especially acetylation is also discussed, with an emphasis on the effects of inhibitors of histone deacetylases on drug-induced behavioral changes. The precise identification of the epigenetic mechanisms that are under the control of drugs of abuse may help to uncover novel targets for the treatment of drug seeking and relapse.