Potent
and selective partial inhibitor ofβ1-containing GABAA
receptors (IC50 values are 4.5, 5.3 and 7.9 nM at α2β1γ1q, a2β1γ1and α2β1γ2sGABAA receptors
respectively). May bind allosterically to a novel site on GABAA
receptor.
Selective antagonist of neuro-steroid potentiation and direct gating of GABAA receptors. Selectively reduces the effects of 5α-reduced steroids compared to 5β-reduced steroids & displays no effect on potentiation evoked by barbiturates & benzodiazepines. Attenuates 3α,5α-THP-induced loss of righting reflex and total sleep time following i.c.v administration in rats.