Endothelin-Induced c-fos Expression in the Rat Forebrain.

The expression of c-fos was analyzed immunohistochemically after injection of endothelin isopeptide into cerebroventricle of the rat. The c-Fos immunoreactivity increased and reached the peak at 1 hr-1.5 hr after the administration of endothelin. Endothelin-1 and endothelin-2 specifically induced c-foss expression in the neurons of paraventricular, supraoptic and periven-tricular nuclei and zona incerta. Endothelin-3 induced c-Fos in the organum vasculosum laminae terminalis in addition to those regions. In these areas, the number of c-Fos-positive neurons increased with a dose (Oto 100 pg of ET) dependent manner. We presume that they are the targeting neurons of central nervous endothelins (ETs).