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Xestospongin C is an equally potent inhibitor of the inositol 1,4,5-trisphosphate receptor and the endoplasmic-reticulum Ca(2+) pumps.

par De Smet, Patrick ;Parys, Jan B.;Callewaert, G;Weidema, A F;Hill, Emita;De Smedt, Humbert;Erneux, Christophe ;Sorrentino, V;Missiaen, Ludwig
Référence Cell calcium, 26, 1-2, page (9-13)
Publication Publié, 1999

Article révisé par les pairs

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Résumé :

Xestospongins, a group of macrocyclic bis-1-oxaquinolizidines isolated from the Australian sponge, Xestospongia species, are potent blockers of the inositol 1,4,5-trisphosphate (IP(3))-induced Ca2+ release in bi-directional Ca2+-flux conditions. We have now studied the effects of xestospongin C on the (45)Ca2+ uptake and the uni-directional (45)Ca2+ efflux in permeabilized A7r5 smooth-muscle cells. Xestospongin C not only inhibits the IP(3)-induced Ca2+ release, but is also an equally potent blocker of the endoplasmic-reticulum Ca2+ pump, while it has no effect on the passive Ca2+ leak. The inhibition of the IP(3) receptor did not depend on the IP(3), Ca2+ or ATP concentration. Xestospongin C can, therefore, not be considered as a selective blocker of IP(3) receptors.