BQ-3020 is a synthetic peptide that acts as a selective and potent ET-B (endothelin B) receptor agonist, a receptor that belongs to the G protein-coupled receptors (GPCR). BQ-3020 is a linear analog of the ET-B receptor ligand endothelin 1 (ET-1), with very close structural similarity to ET-1 compared to other agonists. Several studies have shown that locally active in vivo administration of BQ-3020 causes arterial constriction in healthy human blood vessels¹.

Endothelin receptors include two subtypes: ET-A and ET-B. They are widely distributed in vascular and nonvascular tissues. ET-B receptor has high equal affinity for all endothelin isopeptides². ET-B receptors play an important role in regulating renal function and blood pressure and are expressed in sensory nerves. They are mainly present in medium- and large-sized cell bodies of human trigeminal ganglia³.

Endothelin receptor agonists are being used as useful tools for the functional characterization of these receptors. Studies have shown that administering ET-B receptor agonist into the rat renal medulla, leads to natriuresis and diuresis via a mechanism that is NOS1-dependent⁴.