Alpha subunit position and GABA receptor function.

GABA(A) (gamma-aminobutyric acid type A) receptors are ligand-gated ion channels composed of five subunits, generally two alphas, two betas, and a gamma2. Recent research in which sets of subunits containing alpha1 or alpha6 subunits were artificially linked has revealed the importance of subunit position in determining GABA(A) receptor function. Sensitivity to benzodiazepines depended on juxtaposition of an alpha1 subunit with the gamma2 subunit, whereas sensitivity to furosemide depended only on the presence of an alpha6 subunit and not on its specific location. The major utility of the linked subunit approach is to provide a mechanism for discovering the functional signatures of defined subunit arrangements, and thus a route to identifying such arrangements in vivo.