Xestospongin C (88903-69-9) is a potent and reversible inhibitor of IP3-mediated Ca2+ release, IC50 = 358 nM.1 Experiments with guinea-pig ileum permeabilized with alpha toxin revealed that Xestospongin C inhibits the IP3 receptor but not the ryanodine receptor in SR membranes. In intact smooth muscle cells it inhibits voltage-dependent Ca2+ and K+ currents at a concentration range similar to that at which it inhibits the IP3 receptor. Xestospongin C is a useful tool for probing the involvement of IP3 receptors in cellular signaling.3 Cell permeable.
1) Wilcox et al. (1998), New developments in the molecular pharmacology of the myo-inositol 1,4,5-trisphosphate receptor; Trends Pharmacol. Sci., 19 467
2) Ozaki et al. (2002), Inhibitory mechanism of xestospongin-C on contraction and ion channels in the intestinal smooth muscle; Br. J. Pharmacol., 137 1207
3) Kandasamy et al. (2013), Lipopolysaccharide induces endoplasmic store Ca2+-dependent inflammatory responses in lung microvessels; PLoS One, 8 e63465