Overview
- Reynolds, E.E. et al. (1995) J. Pharmacol. Exp. Ther. 273, 1410.
Alomone Labs PD-156707 inhibits ET-A receptor-mediated Ca2+ mobilization in CHO cells.Dose response plot of PD-156707 (#P-305) inhibition of ET-A receptor-mediated, Endothelin-1-evoked Ca2+ mobilization. IC50 was determined at 0.95 nM. hETA-expressing CHO-K1 cells were loaded with Calcium 6 dye, incubated with PD-156707, and stimulated with 15 nM Endothelin-1 (EC80). Changes in intracellular Ca2+ levels were detected as changes in maximum relative fluorescence (RLU) using FLIPRTETRA™.
PD-156707 is a synthetic compound that acts as a potent and selective antagonist of Endothelin A receptor (ET-A) subtype. PD-156707 is being used to define the physiological and pathological roles of endothelin A receptors. It demonstrates selectivity for ET-A receptor over ET-B receptor1,2.
PD-156707 inhibits endothelin-1 radioligand binding to ET-A and ET-B receptors with Ki of 0.17 nM and 133.8 nM, respectively1 and antagonizes endothelin-1-stimulated phosphoinositide hydrolysis in Ltk cells expressing cloned human endothelin A receptors with an IC50 value of 2.4 nM1.
Endothelin receptors include two subtypes: ET-A and ET-B. They are widely distributed in vascular and nonvascular tissues. ET-A receptors are predominantly expressed in peripheral tissues, especially in vascular smooth muscle tissues to mediate vasoconstriction. They are also present in several regions of the brain. ET-A receptor has high affinity for endothelin-1 and endothelin -2 and relatively low affinity for endothelin-3, while the ET-B receptor has equally high affinity for all endothelin isopeptides3.
