Spatiotemporal dynamics of intracellular calcium in the middle cerebral artery isolated from stroke‐prone spontaneously hypertensive rats
Spatiotemporal dynamics of intracellular calcium in the middle cerebral artery isolated from stroke‐prone spontaneously hypertensive rats
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脑卒中易发性高血压大鼠大脑中动脉细胞内钙的时空动态
DOI：
10.1113/expphysiol.2011.061499
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发表时间：
2012
影响因子：
2.7
通讯作者：
K. Honda
中科院分区：
文献类型：
--
作者：
T. Hashimoto;M. Kiya;H. Ohata;T. Miyazaki;K. Shibata;K. Nobe;K. Honda
采用真实的时间共聚焦激光显微镜研究了易卒中型自发性高血压大鼠（SHR-SP）大脑中动脉（MCA）细胞内钙离子的时空动态变化。在3个月大时（中风前），发现紧张期[Ca 2 +]i的节律性变化先于应用5-HT后的血管舒缩，而不是其他刺激。在1月龄时未观察到这些反应;此外，MCA在卒中后（5月龄）失去了这两种反应。当[Ca 2 +]i在小动脉平滑肌细胞中分析时，[Ca 2 +]i的节律性变化发生在同一周期内。因此，这些进程是同步的。应用100 nm的酮色林和10 μm的尼卡地平后，[Ca ~（2+）]i的同步性节律性变化被消除。用60 nm的Charybdotoxin和10 μm的cyclopiazonic acid处理也显著降低了[Ca 2 +]i的节律性升高。此外，[Ca 2 +]i的节律性变化在100 μm甘珀酸（一种间隙连接阻断剂）处理后变得不同步。连接蛋白45 mRNA和蛋白表达均在SHR-SP的MCA中升高。综上所述，这些发现表明MCA [Ca 2 +]i的节律性变化依赖于5-HT 2受体介导的钙从细胞内储存释放，这反过来又激活电压依赖性钙通道，使钙流入平滑肌细胞。随后，Charybdotoxin敏感性钾通道被激活，并提供负反馈途径来调节[Ca 2 +]i。此外，发现平滑肌细胞中[Ca 2 +]i节律性变化的协调同步依赖于间隙连接。
The spatiotemporal dynamics of intracellular calcium within the middle cerebral artery (MCA) isolated from stroke‐prone spontaneously hypertensive rats (SHR‐SP) were investigated using real‐time confocal laser microscopy. At 3 months of age (prestroke), rhythmical changes in the [Ca2+]i during the tonic phase were found to precede vasomotion following application of 5‐HT, but not other stimuli. These responses were not observed at 1 month of age; moreover, the MCA lost both responses post‐stroke (5 months of age). When [Ca2+]i was analysed in arteriolar smooth muscle cells, rhythmical changes in [Ca2+]i occurred during the same cycle. Thus, these processes were synchronized. The synchronized rhythmical changes in [Ca2+]i were abolished following application of 100 nm ketanserin and 10 μm nicardipine. Treatment with 60 nm charybdotoxin and 10 μm cyclopiazonic acid also significantly reduced rhythmical elevations in [Ca2+]i. In addition, rhythmical changes in [Ca2+]i became unsynchronized following treatment with 100 μm carbenoxolone, a gap junction blocker. Connexin 45 mRNA and protein expression were both elevated in the MCA of SHR‐SP. Taken together, these findings suggest that rhythmical changes in [Ca2+]i of the MCA are dependent upon the 5‐HT2 receptor‐mediated release of calcium from intracellular stores which, in turn, activates voltage‐dependent calcium channels to enable an influx of calcium into smooth muscle cells. Subsequently, charybdotoxin‐sensitive potassium channels are activated and provide a negative feedback pathway to regulate [Ca2+]i. Moreover, the co‐ordinated synchronization of rhythmical changes in [Ca2+]i across smooth muscle cells was found to be dependent upon gap junctions.
大鼠脑血管平滑肌细胞中的Connexin45间隙连接通道。
DOI：
10.1152/ajpheart.2001.281.5.h1890
发表时间：
2001
期刊：
American journal of physiology. Heart and circulatory physiology
影响因子：
--
作者：
Li,X;Simard,JM
通讯作者：
Simard,JM