Identification of endothelin receptors in cultured cerebellar neurons

Abstract We have described the binding of [ 125 I]endothelin-1 (ET-1) to cultured rat cerebellar granule cells. Binding of [ 125 I]ET-1 was specific, saturable, and time-dependent. Scatchard analysis of saturation binding data indicated a single class of high affinity binding site with a K D of 95 pM, and a B max of 8110 receptors/cell. Functionally, the binding of ET-1 stimulated phosphatidylinositide (PI) hydrolysis in a dose- and time-dependent fashion. PI turnover was found to be inhibitable by 1 μM phorbol dibutyrate but not by 1 μg/ml pertussis toxin, suggesting that the ET-1-mediated response is regulated by protein kinase C and a pertussis toxin-insensitive guanine nucleotide (GTP) binding protein.