U93631 is a GABAA receptor ligand of novel chemical structure with IC50 of 100 nM,and has been shown to induce a rapid, time-dependent decay of GABA-induced whole-cell Cl-currents in recombinant GABAA receptors. In the presence of U-93631 at 5 microM, the peak amplitude decreased as a function of GABA concentration, with the half-maximal inhibitory concentration being approximately 100 nm, which is close to the Kd for the high affinity GABA site (85 nM). The binding site for U-93631 on GABAA receptors seems not to overlap with GABA, barbiturate, or benzodiazepine sites, because the drug effect persisted in the presence of excess ligands for those sites. With cloned GABAA receptors composed of only alpha 1 beta 2, beta 2 gamma 2, or alpha 1 gamma 2 subunits, U-93631 also accelerated the decay rate[3].
搜索
