Localization of endothelin-like immunoreactivity in the hypothalamo-neurohypophysial system of the rat after ischemia.

Endothelin is a very powerful endogenous vasoconstrictor substance produced by endothelial cells. To examine the potential role of endothelin as a neuropeptide, we studied its distribution in the neurosecretory system. Endothelin-like immunoreactivity (EN-IR) has been demonstrated by an immunogold method in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the rat. ET-IR was enhanced after ischemia suggesting its modulatory role in neurosecretory functions.