Endothelin Receptor

Endothelin receptors are G protein-coupled receptors (GPCRs) of the β-group of rhodopsin receptors that bind to endothelin ligands, which are 21 amino acid long peptides derived from longer prepro-endothelin precursors. There are at least four types known, ETA, ETB (ETB1, ETB2) and ETC. The ETA receptor is characterized by having high affinity and selectivity for ET-1 and ET-2 compared to ET-3, whereas the ETB receptor has equivalent high affinity for all three endothelin isopeptides.

Endothelins are synthesized in several tissues, including the vascular endothelium (ET-1 exclusively) and smooth muscle cells. Released endothelin binds to the endothelin receptors ETA and ETB, the ETA receptors on vascular smooth muscle cells mediating vasoconstriction, and the ETB receptors on the endothelium linked to nitric oxide (NO) and prostacyclin release.