IRL 2500

IRL 2500 is a synthetic compound that acts as a potent and selective antagonist of ET-B (endothelin B) receptor, a receptor that belongs to the G protein-coupled receptors (GPCR).

IRL 2500 is more selective for human ET-B over ET-A receptor and can be used to delineate responses mediated by the ETB receptor¹. IRL 2500 demonstrates IC₅₀ values of 1.3 nM and 94 nM for human ETB and ETA receptor expressed in transfected Chinese hamster ovary cells respectively¹.

Several in vitro studies have shown that IRL 2500 can inhibit the sarafotoxin S6c-mediated contraction of the dog saphenous vein and the sarafotoxin S6c-induced relaxation of the preconstricted rabbit mesenteric artery. IRL 2500 also attenuates the IRL 1620-mediated increase in renal vascular resistance and decrease in arterial pressure in the anesthetized rat^1,2.

Endothelin receptors are widely distributed in vascular and nonvascular tissues. ET-B receptor has equally high affinity for all endothelin isopeptides³. 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 ganglia⁴.