A computational model of urinary bladder smooth muscle syncytium
A computational model of urinary bladder smooth muscle syncytium
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DOI：
10.1007/s10827-014-0532-6
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发表时间：
2015-02-01
影响因子：
1.2
通讯作者：
Manchanda, Rohit
中科院分区：
文献类型：
--
作者：
Appukuttan, Shailesh;Brain, Keith L.;Manchanda, Rohit
某些平滑肌，如膀胱逼尿肌，表现出各种不同的峰值，其振幅和时间过程明显不同。这种多样性的起源尚不清楚，但通常归因于平滑肌的合胞性及其分布的神经支配。为了帮助澄清这些问题，我们在这里提出了一个三维电模型的合胞体平滑肌开发利用室室建模技术，特别提到膀胱逼尿肌。模型参数值来源于实验数据。该模型在不同的刺激模式下进行了实验验证，结果与理论预测和实验观察一致。模型输出也满足电张力电位的空间扩散和时间衰减的相关性以及阈下电位的幅频直方图正偏斜等电合胞特征的标准，并得出有趣的结论。通过对不同大小合胞体的分析，发现21立方的大小可以被认为是电无限大合胞体的临界最小尺寸。根据实验结果，我们推测在逼尿肌中存在电性次无限束。此外，紧密间隔的细胞之间缺乏一致的活动可能意味着，与直觉相反，这些细胞之间存在高效的电耦合。因此，该模型为解释合胞组织中的电活动提供了一个启发式平台。
Certain smooth muscles, such as the detrusor of the urinary bladder, exhibit a variety of spikes that differ markedly in their amplitudes and time courses. The origin of this diversity is poorly understood but is often attributed to the syncytial nature of smooth muscle and its distributed innervation. In order to help clarify such issues, we present here a three-dimensional electrical model of syncytial smooth muscle developed using the compartmental modeling technique, with special reference to the bladder detrusor. Values of model parameters were sourced or derived from experimental data. The model was validated against various modes of stimulation employed experimentally and the results were found to accord with both theoretical predictions and experimental observations. Model outputs also satisfied criteria characteristic of electrical syncytia such as correlation between the spatial spread and temporal decay of electrotonic potentials as well as positively skewed amplitude frequency histogram for sub-threshold potentials, and lead to interesting conclusions. Based on analysis of syncytia of different sizes, it was found that a size of 21-cube may be considered the critical minimum size for an electrically infinite syncytium. Set against experimental results, we conjecture the existence of electrically sub-infinite bundles in the detrusor. Moreover, the absence of coincident activity between closely spaced cells potentially implies, counterintuitively, highly efficient electrical coupling between such cells. The model thus provides a heuristic platform for the interpretation of electrical activity in syncytial tissues.