Rapid Ca2+ refilling system of intracellular store(s) in human vascular endothelial cells.
Using a fura-2 method, cytosolic Ca2+ concentration [( Ca2+]i) was measured in endothelial cell monolayers from human umbilical vein. In the presence of 1.5 mM Ca2+, bradykinin (BK) induced a rapid (within 15 sec) and dose-dependent (10(-8)-10(-6) M) increase in [Ca2+]i, consisting of an initial peak and a subsequent sustained phase. The pretreatment with 3 mM EGTA for 1 min caused a significant reduction in [Ca2+]i levels both of the basal (p less than 0.05) and BK-stimulated initial peak (p less than 0.001). However, the BK-stimulated initial peak was retained in magnitude for at least 5 min under the treatment with EGTA. In contrast, the sustained phase was completely abolished by EGTA treatment. The BK-stimulated Ca2+ transient, once having been completely inhibited by ionomycin (10(-6) M) in the presence of EGTA, was rapidly (within 2 min) recovered to the untreated level by replacing it with fresh medium containing 1.5 mM Ca2+. The present results indicated that BK mobilized Ca2+ from both intracellular and extracellular space(s) and suggest the presence of an extracellular Ca2(+)-dependent rapid refilling system of intracellular Ca2+ store(s) in human vascular endothelial cells.
Takata
S
S
Department of Medicine, Kobe University School of Medicine, Japan.
Fukase
M
M
Takagi
Y
Y
Tokunaga
O
O
Fujita
T
T
D001572:Benzofurans; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D013050:Spectrometry, Fluorescence; D014471:Umbilical Veins
D001572:Benzofurans; D005456:Fluorescent Dyes; D004533:Egtazic Acid; D015759:Ionomycin; D001920:Bradykinin; D002118:Calcium; D016257:Fura-2