either physically relax (e.g. histone acetylation) or remodel (e.g. SWI-SNF-dependent nucleosome remodeling) chromatin structure, or provide docking sites to recruit additional transcriptional co-activators or repressors [24]. Such modifications include histone acetylation, phosphorylation, and methylation, among several others, which together determine the activity of the underlying gene [19, 24]. This review discusses the recent evidence that changes in histone acetylation, and the enzymes which control it, contribute to drug-induced alterations in gene expression and behavior. While histone acetylation is the best studied modification in brain, it should be emphasized that other chromatin modifications typically occur in parallel and also likely participate in the long-term plasticity underlying drug addiction.
