The endothelin family consists of highly potent vasoconstrictive peptides. Three endogenous isoforms are known to exist - ET-1, ET-2 and ET-3. Due to their physiological role as vasoactive peptides, endothelins have been linked to certain cardiac, vascular and renal diseases; endothelin antagonists may therefore play an important role in the treatment of these conditions. Two distinct endothelin receptors have so far been cloned in mammals, classified as ETA and ETB receptors.
Endothelin Receptor Target Files
Endothelin receptors are widely expressed in all tissues. They are also localized to non-vascular structures including epithelial cells, glia and neurons. The principal physiological role of endothelin receptors is the maintenance of vascular tone. They also have comitogenic activity, potentiating the effects of other growth factors such as PDGF.
|Receptor Subtype||ETA Receptors||ETB Receptors|
|Transduction Mechanism||7-TM, ↑ PI turnover → ↑ Ca2+i.c., ↑ Ca2+ influx||7-TM, ↑ PI turnover → ↑ Ca2+i.c., ↑ Ca2+ influx|
|Primary Locations||Vascular smooth muscle||Vascular endothelial cells|
|Tissue Functions||Vasoconstriction, positive ionotrope, cell proliferation||Vasodilatation, bronchoconstriction, vasoconstriction, cell proliferation|
|Endogenous Ligand Potency||ET-1 = ET-2 > ET-3||ET-1 = ET-2 = ET-3|
|Key Compounds||Ki Values (nM)|
|Selective ETB Agonists||
Sarafotoxin S6c (1175)
FR 139317 (1210)
BMS 182874 (1441)
CI 1020 (2942)
* IC50 values