Endothelin-1 is one of the there isoforms of endothelin (identified as ET-1, -2, -3) with varying regions of expression and binding to at least four known endothelin receptors, ETA, ETB1, ETB2 and ETC.

Endothelins are the most potent vasoconstrictors known. In a healthy individual, a delicate balance between vasoconstriction and vasodilation is maintained by endothelin and other vasoconstrictors as well as nitric oxide, prostacyclin, and other vasodilators. The ubiquitous distribution of endothelin peptides and receptors implicates its involvement in a wide variety of physiological and pathological processes in the body. Among numerous diseases potentially occurring from endothelin dysregulation are several types of cancer, cerebral vasospasm following subarachnoid hemorrhage, arterial hypertension, and other cardiovascular disorder, pain mediation, type II diabetes, etc [2][3].