Chaotic electrical activity of living -cells in the mouse pancreatic islet

To test for chaotic dynamics of the insulin producing β -cell and explore its biological role, we observed the action potentials with the perforated patch clamp technique, for isolated cells as well as for intact cells of the mouse pancreatic islet. The time series obtained were analyzed using nonlinear diagnostic algorithms associated with the surrogate method. The isolated cells exhibited short-term predictability and visible determinism, in the steady state response to 10 mM glucose, while the intact cells did not. In the latter case, determinism became visible after the application of a gap junction inhibitor. This tendency was enhanced by the stimulation with tolbutamide. Our observations suggest that, thanks to the integration of individual chaotic dynamics via gap junction coupling, the β -cells will lose memory of fluctuations occurring at any instant in their electrical activity more rapidly with time. This is likely to contribute to the functional stability of the islet against uncertain perturbations.