Model Status

This CellML model runs in OpenCell and COR but does not recreate the published results. The model is based on the authors original XPPAUT.ode file which can be found at www.math.fsu.edu/~bertram/software/islet/BJ\_05. The units have been checked and they are consistent. We are unsure why the CellML model is not recreating the published results.

Model Structure

ABSTRACT: 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.

The original paper reference is cited below:

Intra- and inter-islet synchronization of metabolically driven insulin secretion, Morten Gram Pedersen, Richard Bertram, and Arthur Sherman, 2005,Biophysical Journal , 89, 107-119. PubMed ID: 15834002