In a study comparing gene expression profiles in the prefrontal cortex of WSP and WSR mice subjected to 72-h ethanol vapor inhalation and sacrificed 3 weeks later, a large set of transcripts involved in histone acetylation and deacetylation was down-regulated in WSR mice, but up-regulated in WSP mice, suggesting that epigenetic modifications may partly underlie persistent gene regulation during protracted abstinence [35]. Enrichment for genes involved in transcriptional repression through epigenetic modifications (histone deacetylation and DNA methylation) was also detected in the nucleus accumbens of C57Bl/6N mice subjected to four cycles of four 18-h two-bottle choice (10% w/v ethanol/water) drinking sessions, followed by four days of ethanol deprivation, and sacrificed 6 days after the last drinking session [29].
