Analyzing changes in histone acetylation at specific gene promoters via quantitative ChIP (qChIP) has demonstrated a key role of this modification in regulating gene expression in response to drugs of abuse [34, 52–54]. However, qChIP is relatively low throughput and is generally used to study carefully chosen candidate genes. Therefore, coupling ChIP to genome-wide microarrays (ChIP-chip) or massively parallel sequencing (ChIP-seq) provides the technology necessary to simultaneously identify drug-induced changes in histone acetylation throughout the genome, and such analyses have now been performed to assess cocaine action on chromatin structure in the NAc [67].
