Responses of individual smooth muscle cells to sympathetic stimulation visualized within the arterial wall using confocal microscopy

我们对血管平滑肌细胞的交感神经控制进行了研究，得到的结果使传统的观点得到了重新考虑。利用共聚焦显微镜，我们成功地显示了大鼠尾动脉壁内单个平滑肌细胞在血管周围交感神经网络活动时的[Ca^&lt；2&gt；]_i变化。由于不同细胞的钙振荡阶段不同，许多细胞的平均值似乎是一个恒定的反应。因此，以前的测量未能检测到振荡。此外，每个振荡在细胞内以大约20微米/S的速度传播，由于细胞内钙离子的释放而以钙波的形式传播。因此，我们的研究结果表明，细胞内钙储备在调节血管平滑肌收缩中起着重要作用。我们还清楚地表明，钙振荡在细胞功能的调节中是重要的。

We studied the sympathetic control of vascular smooth muscle cells and obtained results that make the conventional view to be reconsidered. Using a confocal microscopy, we succeeded in visualizing [Ca^<2+>]_i change in individual smooth muscle cells in situ within the wall of rat tail artery in response to perivascular sympathtetic nerve network activities. Unlike the previous expectation that each smooth muscle cell respond with a constant [Ca^<2+>]_i rise to constant sympathetic stimulation, individual cells are shown to respond in intermittent rises in [Ca^<2+>]_i (Ca^<2+> oscillations). As the phases of Ca^<2+> oscillations differ from cell to cell, the average of many cells appear as if a constant response. Therefore, previous measurements failed to detect the oscillations. Furthermore, each oscillation propagated at a velocity of about 20 mum/s within the cell as Ca^<2+> wave due to release of Ca^<2+> from internal stores. Our results therefore demonstrate that intracellular Ca^<2+> stores play important roles in the regulation of vascular smooth muscle contraction. We have also shown clearly that Ca^<2+> oscillations are important in the regulation of cell functions.