Donnadieu E, Bourguignon L Y
Department of Cell Biology and Anatomy, University of Miami Medical School, Florida 33101, USA.
Cell Calcium. 1996 Jul;20(1):53-61. doi: 10.1016/s0143-4160(96)90050-0.
In this study we have monitored the change of intracellular Ca2+ concentrations in the cytosol ([Ca2+]c) and the mitochondria ([Ca2+]m) of single bovine endothelial cells following treatment with bradykinin (BK). Using laser scanning confocal microscopy, we have found that the Ca2+ indicator, Fluo-3, is compartmentalized in the mitochondria of endothelial cells loaded with Fluo-3/AM. After BK stimulation, the pattern of Ca2+ increase in the cytosol is different from that in the mitochondria. The amplitude of the Ca2+ rise in the mitochondria is higher than that in the cytosol. Further analysis using rapid scanning measurements indicates that the [Ca2+]c increase is very fast after BK addition and reaches a maxima level within 400 ms. In contrast, the [Ca2+]m increase appears to be biphasic with an initial rapid increase (concomitant with the [Ca2+]c increase) followed by a slower [Ca2+]m increase before reaching a maximal level (within 5 s of BK treatment). The differential Ca2+ signaling pattern between the cytosol and the mitochondria suggests that the intracellular Ca2+ concentrations needed to regulate various Ca(2+)-dependent enzymes located in these two compartments are different during BK-induced endothelial cell activation.
在本研究中，我们监测了用缓激肽（BK）处理后单个牛内皮细胞胞质溶胶（[Ca2+]c）和线粒体（[Ca2+]m）中细胞内Ca2+浓度的变化。使用激光扫描共聚焦显微镜，我们发现Ca2+指示剂Fluo-3在加载了Fluo-3/AM的内皮细胞线粒体中呈区室化分布。BK刺激后，胞质溶胶中Ca2+增加的模式与线粒体中的不同。线粒体中Ca2+升高的幅度高于胞质溶胶中的。使用快速扫描测量的进一步分析表明，添加BK后[Ca2+]c增加非常迅速，并在400毫秒内达到最大值水平。相比之下，[Ca2+]m增加似乎是双相的，最初快速增加（与[Ca2+]c增加同时发生），随后在达到最大水平之前（BK处理后5秒内）[Ca2+]m增加较慢。胞质溶胶和线粒体之间不同的Ca2+信号模式表明，在BK诱导的内皮细胞激活过程中，调节位于这两个区室中的各种Ca(2+)依赖性酶所需的细胞内Ca2+浓度是不同的。
