Refilling of endothelial calcium stores without bypassing the cytosol

[摘要]

The present study was undertaken to define the route of Ca²⁺ used for refilling of intracellular Ca²⁺ stores in endothelial cells. Ca²⁺ stores, after emptying with bradykinin in Ca²⁺ free solution and termination of the stimulation with the bradykinin antagonist, Hoe 140, were allowed to refill by addition of Ca²⁺. Refilling was prevented by 2,5-di(tert-butyl)-1,4-benzohydroquinone (BuBHQ), an inhibitor of microsomal Ca²⁺ sequestration. BuBHQ induced large increases in the cytosolic Ca²⁺ concentration during the refilling phase. This finding is not compatible with a model proposing Ca²⁺ uptake into the stores directly from the extracellular space but provides evidence for uptake from the cytosolic compartment.

[学科分类] 生物化学/生物物理

[关键词] Endothelial cell;Intracellular Ca2+ store;Calcium uptake inhibition;2;5-Di(tert-butyl)-1;4-benzohydroquinone;[Ca2+]c;cytosolic free calcium concentration;[Ca2+]e;extracellular Ca2+;BuBHQ;2;5-di(tert-butyl)-1;4-benzo-hydroquinone;InsP3;inositol 1;4;5-trisphosphate;InsP4;inositol 1;3;4;5-tetrakisphosphate