Pedersen Morten Gram, Bertram Richard, Sherman Arthur
Department of Mathematics, Technical University of Denmark, Kgs. Lyngby, Denmark.
Biophys J. 2005 Jul;89(1):107-19. doi: 10.1529/biophysj.104.055681. Epub 2005 Apr 15.
Insulin secretion from pancreatic beta-cells is pulsatile with a period of 5-10 min and is believed to be responsible for plasma insulin oscillations with similar frequency. To observe an overall oscillatory insulin profile it is necessary that the insulin secretion from individual beta-cells is synchronized within islets, and that the population of islets is also synchronized. We have recently developed a model in which pulsatile insulin secretion is produced as a result of calcium-driven electrical oscillations in combination with oscillations in glycolysis. We use this model to investigate possible mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model "liver," which responds to the level of insulin secretion by adjusting the blood glucose concentration in an appropriate way. Since all islets are exposed to the blood, the distributed islet-liver system can synchronize the individual islet insulin oscillations. Thus, we demonstrate how intra-islet and inter-islet synchronization of insulin oscillations may be achieved.
胰腺β细胞分泌胰岛素具有脉动性，周期为5至10分钟，据信这是导致血浆胰岛素以类似频率振荡的原因。为了观察整体的胰岛素振荡情况，胰岛内单个β细胞的胰岛素分泌必须同步，并且胰岛群体之间也需同步。我们最近开发了一个模型，其中脉动性胰岛素分泌是由钙驱动的电振荡与糖酵解振荡共同产生的。我们使用这个模型来研究胰岛内和胰岛间同步的可能机制。我们表明，电耦合足以使电爆发放电活动和代谢振荡同步。我们还证明，胰岛可以通过对一个简单的“肝脏”模型产生相互影响来相互同步，该模型通过以适当方式调节血糖浓度来响应胰岛素分泌水平。由于所有胰岛都暴露于血液中，分布式胰岛-肝脏系统可以使各个胰岛的胰岛素振荡同步。因此，我们展示了胰岛素振荡的胰岛内和胰岛间同步是如何实现的。
