GABAA receptors: subtypes, regional distribution, and function.

Modulatory agents of gamma-aminobutyric acid type A (GABAA) receptors have been widely used for more than 40 years to treat anxiety, epilepsy, and sleep disorders; these drugs are generally safe, well tolerated, and effective. Recently, there has been a substantial growth in understanding of the mechanism of action of these drugs, which act at different sites on GABAA receptors. A variety of GABAA receptor subtypes with distinct functional roles have been characterized and an evolving awareness of GABAA receptor modulation holds promise for the future development of new, more sophisticated drug interventions that can elicit more selective effects by targeting specific subtypes of GABAA receptors. Advances in genetic engineering have led to the development of transgenic mouse models that have further refined our understanding of the pharmacology and physiology for various GABAA receptor subunits.