Risk of AD has a substantial genetic component, with heritability of 0.52–0.64 (Bienvenu et al., 2011; Kendler, 2001). GABA (gamma-aminobutyric acid) is the most abundant and widespread inhibitory neurotransmitter in the central nervous system. The actions of GABA are mediated by receptors belonging to two major classes, termed GABAA and GABAB (Chu et al., 1990). Specifically, GABAA receptors, which are coupled with chloride channels, have been suggested to contribute to ethanol’s actions (Chu et al., 1990; Korpi et al., 2007). Functional mammalian GABAA receptors are formed by the assembly of five subunit proteins, with the usual subunit arrangement of two alpha, two beta, and one gamma or delta subunit (Olsen et al., 2007; Tretter et al., 1997). GABAA receptors are the principal site of action of benzodiazepines (Mohler et al., 2002). These receptors also mediate several behavioral effects of alcohol, and the molecular mechanisms mediating these effects are under current investigation (Korpi et al., 2007; Olsen et al., 2007).
