ASTROCYTES ARE TARGET-CELLS FOR ENDOTHELINS AND SARAFOTOXIN

Abstract: Endothelin‐I, endothelin‐3, and the snake venom toxin sarafotoxin 56b stimulate the hydrolysis of phosphatidylinositol by phospholipase C with similar potencies in primary cultures of astrocytes prepared from rat brain cortex. In indo I‐loaded cells, endoth elin‐I, endothelin‐2, endothelin‐3, and sarafotoxin induce the rapid mobilization of intracellular Ca2+ stores and promote a more slowly developing influx of Ca2*+. These responses were insensitive to pertussis toxin and to inhibitors of cyclooxygenase and lipoxygenase. Similar actions of endothelins and sarafotoxin were observed using astrocytes from the cerebellum and glioma cells from the C6 and NN cell lines. The endthelin receptor of astrocytes differs from the receptor previously characterized in endothelial cells from brain microvessels in that it has a high affnity for endothelin‐3. Thus, brain endothelin‐l and endothelin‐3 have different target cells in the brain and may have different functions. Copyright © 1990, Wiley Blackwell. All rights reserved