Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and control an integral membrane chloride channel. GABA-A receptors are the most prevalent inhibitory neurotransmitter receptors in the brain. Several isoforms have been cloned, and they belong to a superfamily which includes nicotinic receptors, glycine receptors, and 5HT-3 receptors. Most GABA-A receptors have separate modulatory sites sensitive to benzodiazepines and to barbiturates.