Propagated endothelial Ca2+ waves and arteriolar dilation in vivo -: Measurements in Cx40BAC-GCaMP2 Transgenic mice
Propagated endothelial Ca2+ waves and arteriolar dilation in vivo -: Measurements in Cx40BAC-GCaMP2 Transgenic mice
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DOI：
10.1161/circresaha.107.149484
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发表时间：
2007-12-07
影响因子：
20.1
通讯作者：
Kotlikoff, Michael I.
中科院分区：
文献类型：
--
作者：
Tallini, Yvonne N.;Brekke, Johan Fredrik;Kotlikoff, Michael I.
为了研究体内内皮细胞（EC）特异性Ca 2+信号传导，我们设计了转基因小鼠，其中Ca 2+传感器GCaMP 2被置于细菌人工染色体（BAC）内的内源性连接蛋白40（Cx40）转录调控元件的控制下，导致动脉EC，心房肌细胞和心脏浦肯野纤维中的传感器高表达。在Cx40 BAC GCaMP 2小鼠的心室浦肯野细胞网络中，在体外和在体内提睾肌小动脉的EC中获得高信号/噪声Ca 2+信号。微离子电渗乙酰胆碱（ACh）到微动脉触发EC Ca 2+荧光的瞬时增加，传播沿着微动脉的初始速度约为116 μ m/s（n = 28）和衰减的距离高达974 μ m。EC Ca 2+的局部上升之后（延迟，830 +/- 60 ms; n = 8）的血管舒张，进行迅速（mm/s），双向，并进入分支的距离超过1 mm。在中间距离（300至600 μ m），快速进行血管舒张发生而不改变EC Ca 2+，和额外的扩张后发生的Ca 2+波的到来。相比之下，硝普钠的局灶性递送诱发了类似的局部扩张，而没有Ca 2+信号传导或传导。我们的结论是，在体内反应ACh在小动脉包括2个阶段：（1）快速进行的血管舒张启动的局部上升EC Ca 2+，但独立于EC Ca 2+信号在远程网站;（2）较慢的互补扩张与Ca 2+波传播沿着内皮。
To study endothelial cell (EC)-specific Ca2+ signaling in vivo we engineered transgenic mice in which the Ca2+ sensor GCaMP2 is placed under control of endogenous connexin40 (Cx40) transcription regulatory elements within a bacterial artificial chromosome (BAC), resulting in high sensor expression in arterial ECs, atrial myocytes, and cardiac Purkinje fibers. High signal/noise Ca2+ signals were obtained in Cx40BAC-GCaMP2 mice within the ventricular Purkinje cell network in vitro and in ECs of cremaster muscle arterioles in vivo. Microiontophoresis of acetylcholine (ACh) onto arterioles triggered a transient increase in EC Ca2+ fluorescence that propagated along the arteriole with an initial velocity of approximate to 116 mu m/s (n = 28) and decayed over distances up to 974 mu m. The local rise in EC Ca2+ was followed (delay, 830 +/- 60 ms; n = 8) by vasodilation that conducted rapidly (mm/s), bidirectionally, and into branches for distances exceeding 1 mm. At intermediate distances (300 to 600 mu m), rapidly-conducted vasodilation occurred without changing EC Ca2+, and additional dilation occurred after arrival of a Ca2+ wave. In contrast, focal delivery of sodium nitroprusside evoked similar local dilations without Ca2+ signaling or conduction. We conclude that in vivo responses to ACh in arterioles consists of 2 phases: (1) a rapidly-conducted vasodilation initiated by a local rise in EC Ca2+ but independent of EC Ca2+ signaling at remote sites; and (2) a slower complementary dilation associated with a Ca2+ wave that propagates along the endothelium.