Refilling of endothelial calcium stores without bypassing the cytosol.
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.
Lückhoff
A
A
Institute of Applied Physiology, University of Freiburg, FRG.
Busse
R
R
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D006873:Hydroquinones / Q000494:pharmacology; D007700:Kinetics; D013552:Swine
D000975:Antioxidants; D006873:Hydroquinones; C019359:2,5-di-tert-butylhydroquinone; D002118:Calcium