PRESENCE OF NONSELECTIVE TYPE OF ENDOTHELIN RECEPTOR ON VASCULAR ENDOTHELIUM AND ITS LINKAGE TO VASODILATION

We studied the role of non-selective type (ET(B)) of endothelin (ET) receptor in the vasculature, using a ligand specific to the ET(B) receptor, [Glu9]-sarafotoxin S6b ([Glu9]SRTb). Endothelium-containing rat thoracic aorta possessed specific binding sites for I-125-[Glu9]SRTb, which were almost eliminated by removal of the endothelium, while ET-3-specific binding sites were not detected in the endothelium-intact rat aorta. Only ET(B) receptor was detected in the membranes from the endothelium of porcine aorta. [Glu9]SRTb exerted only vasodilation in rat aortic ring. These findings indicate that ET(B) receptors are located on vascular endothelium and linked to vasodilation.