Excitatory effect of dehydroepiandrosterone, its sulphate ester and pregnenolone sulphate, applied by iontophoresis and pressure, on single neurones in the septo-preoptic area of the guinea pig.

When dehydroepiandrosterone (D), its ester sulphate (DS) and pregnenolone sulphate (PS) were applied iontophoretically or by pressure to neurones in the septo-preoptic area, an excitatory effect was observed. DS and PS, applied on the same neurone, always produced a similar effect. When DS and D were tested, some neurones were excited by both steroids whereas others responded to DS but were unaffected by D. DS-, PS- and D-induced responses displayed a short latency in onset and offset, suggesting an action at the membrane level as for other steroids.