Bény J L
Department of Zoology and Animal Biology, University of Geneva, Switzerland.
Am J Physiol. 1990 Mar;258(3 Pt 2):H836-41. doi: 10.1152/ajpheart.1990.258.3.H836.
The membrane potential of endothelial and neighboring (0.1 mm) smooth muscle cells of pig coronary arteries were simultaneously recorded with two microelectrodes. The membrane potential of endothelial cells was -40 +/- 4 mV (n = 9). In these cells bradykinin (250 nM), an endothelium-dependent vasodilator, evoked a transient hyperpolarization (14 +/- 2 mV, n = 9) resembling those already observed in smooth muscles. The similarity between the electrical signal of pre- and postmyoendothelial junctions suggested an electrical coupling between endothelial and smooth muscle cells. However, the injection of the fluorescent dye Lucifer yellow in the recorded cell proved that the cell was endothelial, and in addition, the injection demonstrated the absence of dye coupling between endothelial and smooth muscle cells. Moreover the injection of electrical pulses (0.05-3.5 nA) in the endothelial cell never evoked any electrical response in the smooth muscle. By contrast, the smooth muscle cells were electrically coupled-together. These results do not support the idea that the endothelial cell hyperpolarization caused by bradykinin is transmitted to smooth muscle cells by electrotonic spreading.
用两个微电极同时记录猪冠状动脉内皮细胞和相邻（0.1毫米）平滑肌细胞的膜电位。内皮细胞的膜电位为-40±4毫伏（n = 9）。在这些细胞中，内皮依赖性血管舒张剂缓激肽（250纳摩尔）引起短暂的超极化（14±2毫伏，n = 9），类似于在平滑肌中已经观察到的超极化。肌内皮连接前后的电信号相似性表明内皮细胞和平滑肌细胞之间存在电耦合。然而，向记录的细胞中注射荧光染料路西法黄证明该细胞是内皮细胞，此外，注射证明内皮细胞和平滑肌细胞之间不存在染料耦合。此外，向内皮细胞中注入电脉冲（0.05 - 3.5纳安）从未在平滑肌中引起任何电反应。相比之下，平滑肌细胞之间存在电耦合。这些结果不支持缓激肽引起的内皮细胞超极化通过电紧张扩布传递到平滑肌细胞的观点。
