Gamma aminobutyric acid (GABA) is one of the main inhibitory neurotransmitters in the mammalian brain. Its effects are realized via GABA(A), GABA(B), and GABA(C) receptors. GABA(A) is the most abundant type of GABA receptors. It consists of six classes of subunits, alpha, beta, gamma, delta, epsilon, and chi. Acute and chronic exposures to ethanol are accompanied by changes in structure and function of GABA(A) receptors. These changes may be a basis for altered behavior seen in alcoholism.