PT - JOURNAL ARTICLE AU - A Y Valeyev AU - J L Barker AU - R A Cruciani AU - G D Lange AU - V V Smallwood AU - L C Mahan TI - Characterization of the gamma-aminobutyric acidA receptor-channel complex composed of alpha 1 beta 2 and alpha 1 beta 3 subunits from rat brain. DP - 1993 May 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 985--991 VI - 265 IP - 2 4099 - http://jpet.aspetjournals.org/content/265/2/985.short 4100 - http://jpet.aspetjournals.org/content/265/2/985.full SO - J Pharmacol Exp Ther1993 May 01; 265 AB - The cloned alpha 1, beta 2 and beta 3 subunits of the gamma-aminobutyric acid (GABA)A receptor-channel complex from rat brain were coexpressed as alpha beta complexes in cultured Chinese hamster ovary cells. Electrophysiological characterization of alpha 1 beta 2 and alpha 1 beta 3 receptor subunit arrangements was performed utilizing patch electrodes in the whole-cell recording configuration. The reversal potential of the current activated by either GABA or muscimol corresponded to that expected for Cl- ions and was dependent on the Cl- gradient. The dose response to GABA for activation of Cl- currents by either subunit combination displayed similar potencies. Currents were partially blocked by the reversible antagonist bicuculline. (-)Pentobarbital was ineffective by itself, but potentiated responses to GABA. The steroid alphaxalone (3 alpha-hydroxy 5 alpha-pregnane 11,20-dione) produced just-detectable inward currents, but did not potentiate GABA-activated currents. Diazepam was completely ineffective. The kinetics and conductance of the Cl- ion channels were inferred from spectral analysis of agonist-induced current fluctuations. Both kinetics and conductance were dependent on agonist structure.