Disulfonic stilbene derivatives open the Ca2+ release channel of sarcoplasmic reticulum.

Journal of Biochemistry
T Kawasaki, M Kasai

Abstract

Ca2+ channels of isolated sarcoplasmic reticulum were incorporated into a planar lipid bilayer and their pharmacological properties were studied. The results show that the channel is a Ca2+-induced Ca2+ release channel like that observed in skinned muscle fibers and isolated vesicles. (i) The open channel probability was increased by the addition of micromolar amounts of Ca2+ to the cis (myoplasmic) side and further increased by millimolar ATP. (ii) The channel was closed by millimolar Mg2+ and micromolar ruthenium red. We found that two disulfonic stilbene derivatives, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and 4-acetoamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), when added to the cis side open the channel and lock it irreversibly at open without changing the single channel conductance. Ca2+ efflux from SR vesicles was also enhanced by SITS and DIDS, as monitored by a tracer assay. Further, Ag+ activated the channel transiently. These results suggest that certain amino and SH residues play important roles in gating the Ca2+ channel.

Citations

Nov 17, 2004·The Journal of General Physiology·Derek R LaverGraham D Lamb
Dec 1, 1993·Pflügers Archiv : European journal of physiology·A Zahradníková, I Zahradník
Feb 1, 1993·Pflügers Archiv : European journal of physiology·R D Harvey
Sep 1, 1996·The American Journal of Physiology·T ObaD F Van Helden
Sep 12, 1996·European Journal of Pharmacology·K Nihonyanagi, T Oba
Mar 1, 1992·The International Journal of Biochemistry·M JoffeM Silove

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