Selective antagonist of neurosteroid potentiation and direct gating of GABAA receptors. Selectively reduces the effects of 5α-reduced steroids compared to 5β-reduced steroids and displays no effect on potentiation evoked by barbiturates and benzodiazepines. Attenuates 3α,5α-THP-induced loss of righting reflex and total sleep time following i.c.v administration in rats. Purity 99%. MW (observed): 350.54