Takano Hiromichi, Dora Kim A, Garland Christopher J
Department of Physiology, Kanazawa Medical University, Japan.
J Smooth Muscle Res. 2005 Dec;41(6):303-11. doi: 10.1540/jsmr.41.303.
Focal application of vasodilators such as acetylcholine (ACh), which evoke arterial hyperpolarization, cause coordinated dilatation along the length of an artery with minimal decay with distance from the site of application. This phenomenon is called spreading vasodilatation. In an artery wall, the endothelium is separated from the surrounding smooth muscle cell layers by an internal elastic lamina (IEL). Adjacent endothelial cells are strongly connected via gap junctions, which can allow direct communication between the cells, including the passage of small molecules and electrical current. Direct communication between an endothelial cell and a smooth muscle cell, through a hole in the IEL, has recently been observed in arteries. Spreading vasodilatation is associated with a spread of hyperpolarization which may be a key mechanism responsible for this spreading arterial vasodilatation. Endothelial cells appear to play an important role in such spread, even though the facilitating mechanisms underlying this spread are as yet unclear. These spreading responses are likely to have an important physiological role in the coordination of blood flow within a vascular network.
诸如乙酰胆碱（ACh）之类的血管扩张剂的局部应用会引起动脉超极化，从而导致动脉沿其长度方向协调扩张，且离应用部位的距离对扩张效果的衰减最小。这种现象称为扩展性血管舒张。在动脉壁中，内皮通过内弹性膜（IEL）与周围的平滑肌细胞层分隔开。相邻的内皮细胞通过缝隙连接紧密相连，缝隙连接可以使细胞之间直接通讯，包括小分子和电流的通过。最近在动脉中观察到内皮细胞与平滑肌细胞之间通过IEL上的一个孔直接通讯。扩展性血管舒张与超极化的传播有关，超极化可能是这种扩展性动脉血管舒张的关键机制。内皮细胞似乎在这种传播中起重要作用，尽管这种传播的促进机制尚不清楚。这些扩展性反应可能在血管网络内的血流协调中具有重要的生理作用。
