expected for genes that are part of the mechanisms of neural plasticity, potentially involved in reaction to all external stimuli including (nonspecific) drug response. Such mechanisms likely include, for instance, epigenetic regulation, e.g., histone acetylation, which appears to participate in long-lasting neural adaptations related to stress and non-specific drug sensitization and possibly dependence (Covington et al., 2009; Romieu et al., 2008; Sanchis-Segura et al., 2009).
