Takata S, Fukase M, Takagi Y, Tokunaga O, Fujita T
Department of Medicine, Kobe University School of Medicine, Japan.
Biochem Biophys Res Commun. 1990 Mar 30;167(3):933-40. doi: 10.1016/0006-291x(90)90613-r.
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.
采用fura-2法，测定人脐静脉内皮细胞单层中的胞质Ca2+浓度[Ca2+]i。在1.5 mM Ca2+存在的情况下，缓激肽（BK）诱导[Ca2+]i迅速（15秒内）且呈剂量依赖性（10(-8)-10(-6) M）升高，包括一个初始峰值和随后的持续阶段。用3 mM EGTA预处理1分钟导致基础[Ca2+]i水平（p<0.05）和BK刺激的初始峰值（p<0.001）均显著降低。然而，在EGTA处理下，BK刺激的初始峰值在幅度上至少保留5分钟。相反，EGTA处理完全消除了持续阶段。在EGTA存在的情况下，一旦离子霉素（10(-6) M）完全抑制了BK刺激的Ca2+瞬变，通过用含有1.5 mM Ca2+的新鲜培养基替换，其迅速（2分钟内）恢复到未处理水平。目前的结果表明，BK从细胞内和细胞外空间动员Ca2+，并提示人血管内皮细胞中存在细胞内Ca2+储存的细胞外Ca2(+)-依赖性快速再填充系统。
