Biological Activity
bq-123 is a potent and selective antagonist of eta endothelin receptor with ki values of 1.4 and 1500 nm for eta and etb receptors, respectively.endothelin receptor is a g protein-coupled receptor. eta receptor increases intracellular-free ca2+. also, activation of eta receptor increases vasoconstriction and blood pressure.bq-123 is a selective eta receptor antagonist. in the eta-expressing cells, bq123 (10-6 m) inhibited endothelin-1 (et-1) (10-6 m)-induced [ca2+]i increase by 95% [1]. in rat vascular smooth muscle cells (vsmc), bq-123 inhibited et-1 receptor binding, cellular contraction, [ca2+ ]i mobilization, [3h]thymidine incorporation, map kinase activation and mtt reduction induced by et-1. however, bq-123 didn’t inhibit angiotensin ii (ang ii)- and arginine vasopressin (avp)-induced increases in map kinase activity and [ca2+]i mobilization [2].in spontaneously hypertensive rats (shr), renin hypertensive rats and normotensive rats, bq-123 (16 nm/kg/min) reduced mean arterial pressure in a dose-dependent way in shr. also, bq-123 lowered blood pressure in both renin hypertensive rats and normotensive rats [3]. in a kidney transplantation rat model with reperfusion injury, bq-123 prevented reperfusion injury and inhibited the synthesis and release of et-1,2 [4].
References
[1]. sakamoto a, yanagisawa m, sawamura t, et al. distinct subdomains of human endothelin receptors determine their selectivity to endothelina-selective antagonist and endothelinb-selective agonists. j biol chem, 1993, 268(12): 8547-8553.
[2]. guo x, okada k, fujita n, et al. inhibitory effect of bq-123 on endothelin-1-stimulated mitogen-activated protein kinase and cell growth of rat vascular smooth muscle cells. hypertens res, 1996, 19(1): 23-30.
[3]. douglas sa, gellai m, ezekiel m, et al. bq-123, a selective endothelin subtype a-receptor antagonist, lowers blood pressure in different rat models of hypertension. j hypertens, 1994, 12(5): 561-567.
[4]. büyükgebiz o, aktan ao, haklar g, et al. bq-123, a specific endothelin (eta) receptor antagonist, prevents ischemia-reperfusion injury in kidney transplantation. transpl int, 1996, 9(3): 201-207.
