Preclinical studies have shown that changes in the expression of subunits of GABAA receptors are implicated in the development of ethanol tolerance and dependence as well as in the cortical excitability associated with withdrawal [14]. In this study we chose to do a comprehensive assessment of gene expression changes in GABAergic genes that encode proteins involved in GABA synthesis, transmission, transport and metabolism. We compared GABAergic gene expression in postmortem total hippocampus from eight alcoholics, eight cocaine addicts and eight controls using RNA-Seq, a deep-sequencing technology that maps the entire transcriptome and provides precise, accurate measurements of the level of transcripts [20], [21]. We used the same RNA Seq method to compare GABAergic gene expression in postmortem total hippocampus from eight selectively bred alcohol-preferring (P) and eight non-preferring (NP) rats.
