Curvature-Dependent Excitation Propagation in Cultured Cardiac Tissue.
Curvature-Dependent Excitation Propagation in Cultured Cardiac Tissue.
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DOI：
10.1134/s0021364011230044
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发表时间：
2012-02
期刊：
影响因子：
1.3
通讯作者：
Agladze K
中科院分区：
文献类型：
--
作者：
Kadota S;Kay MW;Magome N;Agladze K
激发波前的几何形状对传播阻塞和螺旋波的形成起着重要的作用。由于与障碍物的相互作用，波前弯曲超过临界值，可能部分停止传播，出现波破裂，演变成旋转波或再入。这种情况可以解释折返是如何在心脏中自发发生的。我们研究了心脏组织培养中高度弯曲的激发波阵面，发现在正常、非抑制兴奋性的条件下，曲率效应在传播中并不发挥重要作用。狭窄的地峡和障碍物的尖角都不影响非抑制波的传播，而这些地峡和障碍物是产生极端弯曲波阵面的经典对象。只有在利多卡因部分抑制钠通道后，才观察到传播阻滞和波从障碍物边界分离的曲率相关现象。计算机模拟证实了实验观察。对所观察到的现象的解释是指心脏组织由有限大小的细胞组成，使得小于心肌细胞大小的曲率半径失去意义，并且在非抑制组织中，单个细胞能够将兴奋传递到其邻居。
The geometry of excitation wave front may play an important role on the propagation block and spiral wave formation. The wave front which is bent over the critical value due to interaction with the obstacles may partially cease to propagate and appearing wave breaks evolve into rotating waves or reentry. This scenario may explain how reentry spontaneously originates in a heart. We studied highly curved excitation wave fronts in the cardiac tissue culture and found that in the conditions of normal, non-inhibited excitability the curvature effects do not play essential role in the propagation. Neither narrow isthmuses nor sharp corners of the obstacles, being classical objects for production of extremely curved wave front, affect non-inhibited wave propagation. The curvature-related phenomena of the propagation block and wave detachment from the obstacle boundary were observed only after partial suppression of the sodium channels with Lidocaine. Computer simulations confirmed the experimental observations. The explanation of the observed phenomena refers to the fact that the heart tissue is made of finite size cells so that curvature radii smaller than the cardiomyocyte size loses sense, and in non-inhibited tissue the single cell is capable to transmit excitation to its neighbors.