Competitive interaction between endothelin and sarafotoxin: Binding and phosphoinositides hydrolysis in rat atria and brain

Binding studies with the structurally similar vasoconstrictor peptides 125 I-endothelin and 125 I-sarafotoxin b, the former of mammalian origin and the latter derived from snake venom, reveal their mutually exclusive binding to rat atrium and various regions of the rat brain. In these tissues endothelin, like sarafotoxin, induces phosphoinositide hydrolysis which is in part Ca 2+ -independent. It is suggested that endothelins and sarafotoxins share common binding sites and mechanisms of action.