Endothelin/sarafotoxin receptor induced phosphoinositide turnover: effects of pertussis and cholera toxins and of phorbol ester.

The induction of phosphoinositide hydrolysis (PI) by endothelin/sarafotoxin (ET/SRTX) receptors in rat heart myocytes was investigated by the use of bacterial toxins as well as a phorbol ester. Both pertussis- and choleratoxin enhanced the stimulation of PI hydrolysis. Phorbol ester treatment of the myocytes for short periods distinguished between two types of PI-hydrolysis, the one induced by endothelins and the other by sarafotoxins. The possible mediation of G-protein (s) in the induction by ET/SRTX receptors of PI-hydrolysis is discussed.