Rintoul Gordon L, Baimbridge Kenneth G
Department of Physiology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3.
Cell Calcium. 2003 Aug;34(2):131-44. doi: 10.1016/s0143-4160(03)00041-1.
The effects of the artificial Ca(2+) buffers EGTA and BAPTA upon histamine-induced Ca(2+) oscillations and calcium waves were studied in HeLa cells. These events were also examined in HeLa cell lines transfected with the intracellular calcium-binding protein calbindin-D28k (CaBP; HeLa-CaBP) or the pCINeo vector alone (HeLa-pCINeo). High concentrations of the Ca(2+) indicators fluo-3 and fura-2 significantly influenced the oscillatory pattern of intracellular Ca(2+) in HeLa-pCINeo cells exposed to 1 microM histamine. Loading cells with low concentrations of the cell-permeant esters of the artificial Ca(2+)-buffers EGTA or BAPTA, resulted in fewer cells with a distinct "baseline" oscillatory pattern, and loading with higher concentrations of BAPTA almost completely abolished them. In HeLa-CaBP cells, stimulation with 1 microM histamine resulted in individual Ca(2+) spikes that had a flattened profile when compared to control cells; peak Ca(2+) was lowered, the rate of increase in Ca(2+) was slower and transients were prolonged. When compared to HeLa-pCINeo cells, loading with EGTA or BAPTA, or transfection of CaBP, significantly reduced the propagation velocity (by up to 60%) of Ca(2+) waves induced by exposure to 100 microM histamine. We conclude that intracellular Ca(2+) buffering exerts a significant influence on global Ca(2+) responses in HeLa cells and the propagation of Ca(2+) waves that underlie them. The relative effectiveness of different Ca(2+) buffers, including CaBP, appears to be particularly dependent upon the rapidity of their binding kinetics, with BAPTA being the most effective.
在HeLa细胞中研究了人工钙缓冲剂乙二醇双（2-氨基乙基醚）四乙酸（EGTA）和1,2-双（2-氨基苯氧基）乙烷-N,N,N',N'-四乙酸（BAPTA）对组胺诱导的钙振荡和钙波的影响。还在转染了细胞内钙结合蛋白钙结合蛋白-D28k（CaBP；HeLa-CaBP）或单独的pCINeo载体（HeLa-pCINeo）的HeLa细胞系中检查了这些事件。高浓度的钙指示剂荧光素-3和fura-2显著影响暴露于1μM组胺的HeLa-pCINeo细胞中细胞内钙的振荡模式。用低浓度的人工钙缓冲剂EGTA或BAPTA的细胞渗透性酯加载细胞，导致具有明显“基线”振荡模式的细胞减少，而用更高浓度的BAPTA加载几乎完全消除了它们。在HeLa-CaBP细胞中，用1μM组胺刺激导致单个钙尖峰，与对照细胞相比，其轮廓变平；细胞内钙峰值降低，细胞内钙增加速率减慢，瞬变延长。与HeLa-pCINeo细胞相比，用EGTA或BAPTA加载或CaBP转染显著降低了暴露于100μM组胺诱导的钙波的传播速度（高达60%）。我们得出结论，细胞内钙缓冲对HeLa细胞中的整体钙反应及其潜在的钙波传播有显著影响。不同钙缓冲剂（包括CaBP）的相对有效性似乎特别取决于其结合动力学的快速性，其中BAPTA最有效。
