One of alcohol's several central nervous system mechanisms is its affinity for γ-aminobutyric acid (GABA) receptors of the A type (GABA-A). These ligand-gated receptors are involved in most inhibitory neural transmission, and commonly exist in pentameric configurations of two α, two β, and one γ subunits. α2 subunits, which populate limbic and reward-related brain areas, such as the ventral tegmental area (VTA) and nucleus accumbens (Pirker et al., 2000), mediate the anxiolytic effects of benzodiazepines (with which alcohol is cross tolerant), but not its amnestic or sedative effects (Löw et al., 2000). Data specific to alcohol are somewhat more ambiguous (Täuber et al., 2003), but knockout mice lacking the α2 subunit may be less sensitive to alcohol's hypnotic effects (Boehm II et al., 2004).
