Excitation wave propagation as a possible mechanism for signal transmission in pancreatic islets of Langerhans
Excitation wave propagation as a possible mechanism for signal transmission in pancreatic islets of Langerhans
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DOI：
10.1016/s0006-3495(01)76096-1
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发表时间：
2001-03-01
影响因子：
3.4
通讯作者：
Scott, AC
中科院分区：
文献类型：
--
作者：
Aslanidi, OV;Mornev, OA;Scott, AC
响应于葡萄糖的应用，形成胰岛的β细胞开始膜电位和细胞内钙浓度的爆发振荡，诱导细胞分泌胰岛素.直到最近，一直认为由于细胞之间的偶联，单个胰岛中β细胞的爆发活性在整个胰岛中是同步的.然而，在朗格汉斯岛中通常会观察到远处细胞活动的几秒钟时间延迟，这表明可以发生通过胰岛的电波/钙波传播。这项工作提出了实验和理论证据波传播的胰岛。用Fura-2荧光监测胰岛中时空钙动力学的实验清楚地表明了这种波的传播。此外，描述电耦合β细胞簇的模型的数值模拟支持了我们的观点，即实验观察到的钙波是由于通过簇传播的电脉冲。这一观点也得到了独立实验结果的支持。基于模型方程，给出了波速的近似解析表达式，指出了影响波速的参数。我们指出观察到的波作为控制胰岛内胰岛素分泌的信号的可能作用，特别是在任何外部刺激（如胰岛外的高葡萄糖浓度）无法到达的区域。
In response to glucose application, beta -cells forming pancreatic islets of Langerhans start bursting oscillations of the membrane potential and intracellular calcium concentration, inducing insulin secretion by the cells, Until recently, it has been assumed that the bursting activity of beta -cells in a single islet of Langerhans is synchronized across the whole islet due to coupling between the cells. However, time delays of several seconds in the activity of distant cells are usually observed in the islets of Langerhans, indicating that electrical/calcium wave propagation through the islets can occur. This work presents both experimental and theoretical evidence for wave propagation in the islets of Langerhans. Experiments with Fura-2 fluorescence monitoring of spatiotemporal calcium dynamics in the islets have clearly shown such wave propagation. Furthermore, numerical simulations of the model describing a cluster of electrically coupled beta -cells have supported our view that the experimentally observed calcium waves are due to electric pulses propagating through the cluster. This point of view is also supported by independent experimental results. Based on the model equations, an approximate analytical expression for the wave velocity is introduced, indicating which parameters can alter the velocity. We point to the possible role of the observed waves as signals controlling the insulin secretion inside the islets of Langerhans, in particular, in the regions that cannot be reached by any external stimuli such as high glucose concentration outside the islets.