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首页> 外文期刊>American Journal of Physiology >Behavior of ectopic surface: effects of beta-adrenergic stimulation and uncoupling.
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Behavior of ectopic surface: effects of beta-adrenergic stimulation and uncoupling.

机译：异位表面的行为：β-肾上腺素刺激和解偶联的影响。

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摘要

By using both experimental and theoretical means, we have addressed the progression of ectopic activity from individual cardiac cells to a multicellular two-dimensional network. Experimental conditions that favor ectopic activity have been created by local perfusion of a small area of cardiomyocyte network (I-zone) with an isoproterenol-heptanol containing solution. The application of this solution initially slowed down and then fully blocked wave propagation inside the I-zone. After a brief lag period, ectopically active cells appeared in the I-zone, followed by evolution of the ectopic clusters into slowly propagating waves. The changing pattern of colliding and expanding ectopic waves confined to the I-zone persisted for as long as the isoproterenol-heptanol environment was present. On restoration of the control environment, the ectopic waves from the I-zone broke out into the surrounding network causing arrhythmias. The observed sequence of events was also modeled by FitzHugh-Nagumo equations and included a cell's arrangement of two adjacent square regions of 20 x 20 cells. The control zone consisted of well-connected, excitable cells, and the I-zone was made of weakly coupled cells (heptanol effect), which became spontaneously active as time evolved (isoproterenol effect). The dynamic events in the system have been studied numerically with the use of a finite difference method. Together, our experimental and computational data have revealed that the combination of low coupling, increased excitability, and spatial heterogeneity can lead to the development of ectopic waves confined to the injured network. This transient condition appears to serve as an essential step for the ectopic activity to "mature" before escaping into the surrounding control network.
机译：通过使用实验和理论手段，我们已经解决了异位活动从单个心脏细胞到多细胞二维网络的进展。通过使用含有异丙肾上腺素-庚醇的溶液对小面积的心肌细胞网络（I区）进行局部灌注，已经创造了有利于异位活性的实验条件。该解决方案的应用最初减慢了速度，然后完全阻止了I区内部的波传播。在短暂的滞后之后，异位活性细胞出现在I区，随后异位簇进化为缓慢传播的波。只要存在异丙肾上腺素-庚醇环境，碰撞和扩张的异位波就一直局限于I区。在恢复控制环境后，来自I区的异位波进入周围的网络，引起心律不齐。观察到的事件顺序也由FitzHugh-Nagumo方程建模，包括一个单元的20 x 20个单元的两个相邻正方形区域的排列。对照区由连接良好的兴奋性细胞组成，而I区由弱耦合细胞组成（庚醇效应），随着时间的流逝，该区域会自发激活（异丙肾上腺素效应）。使用有限差分方法对系统中的动态事件进行了数值研究。总之，我们的实验和计算数据表明，低耦合，增加的兴奋性和空间异质性的结合可以导致局限性电波发展，局限在受损的网络中。这种暂时状态似乎是异位活动逃逸到周围控制网络之前“成熟”的必不可少的步骤。

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