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, ET_A, ET_B (ET_B1, ET_B2) and ET_C. The ET_A receptor is characterized by having high affinity and selectivity for ET-1 and ET-2 compared to ET-3, whereas the ET_B 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 ET_A and ET_B, the ET_A receptors on vascular smooth muscle cells mediating vasoconstriction, and the ET_B receptors on the endothelium linked to nitric oxide (NO) and prostacyclin release.