Testosterone reduces refractory period of stria terminalis neurons in the rat brain.

The absolute refractory period of neurons projecting from the corticomedial amygdala to the medial preoptic-anterior hypothalamic junction in rats was significantly increased by castration (from 1.01 to 1.61 milliseconds) and decreased again by testosterone (from 1.48 to 0.97 millisecond). Corticomedial amygdala neurons which projected to the capsule of the ventromedial nucleus of the hypothalamus were unaffected. These results demonstrate a specific, direct neuronal effect of testosterone.