Stochasticity in cellular models of calcium signaling

Martin Falcke*

Mathematical Cell Physiology, Max Delbrück Centre for Molecular Medicine, Berlin, Germany

*martin.falcke@mdc-berlin.de

Ca²⁺ oscillations have been considered to obey deterministic dynamics for almost two decades. We show for five cell types that Ca²⁺ oscillations are instead a sequence of random spikes. The standard deviation of the interspike intervals (ISIs) of individual spike trains is similar to the average ISI; it increases approximately linearly with the average ISI; and consecutive ISIs are uncorrelated. Decreasing the effective diffusion coefficient of free Ca²⁺ using Ca²⁺ buffers increases the average ISI and the standard deviation in agreement with the idea that individual spikes are caused by random wave nucleation. Array-enhanced coherence resonance leads to regular Ca²⁺ oscillations with small standard deviation of ISIs.

References:

A. Skupin, H. Kettenmann, U. Winkler, M. Wartenberg, H. Sauer, St. Tovey, C. Taylor, M. Falcke, “How does intracellular Ca²⁺ oscillate: by chance or by the clock?”, Biophysical Journal 94(6) (2008) 2404-2411

M. Falcke, “Reading the Patterns in Living Cells - The Physics of Ca²⁺ Signaling”, Advances in Physics, 53(3) (2004) 255-440

A. Skupin, M. Falcke, "Statistical properties and information content of calcium oscillations", Genome Informatics, 18 (2007) 44-53