Three apparent receptor subtypes for the endothelin/sarafotoxin family

Abstract

Competition binding experiments performed with 125 I‐sarafotoxin (SRTX)‐b and SRTX‐b, SRTX‐c and endothelin (ET‐1 and ET‐3) using homogenates of rat right and left atria, aorta, uterus, cerebellum and caudate putamen indicated heterogeneity of the ET/SRTX receptor. The evidence pointed to the existence of three receptor subtypes: a high‐affinity ET‐1/SRTX‐b subtype typical of smooth muscle (E‐S α receptor), a high‐affinity SRTX‐c subtype typical of the cerebellum (E‐S β receptor), and a less selective subtype typical of the caudate putamen that binds all of these peptides with high affinity (E‐S γ receptor).