Stochastic E4ects in Intercellular Calcium Spiking in Hepatocytes

We carry out a Monte Carlo simulation of stochastic e!ects for two models of intercellular calcium wave propagation in rat hepatocytes. Both models involve gap junction di!usion by a second messenger. We "nd that, in general, the stochastic e!ects improve agreement with experiment, for a reasonable choice of model parameters. Both stochastic models exhibit baseline #uctuations and variations in the peak heights of Ca2̀ . In addition, we "nd for one model that there is a distribution of latency times, rather than a single latency time, with a distribution width which is comparable to the experimental observation of spike widths. We also "nd for the other model with low gap junction di!usion that it is possible for cell multiplets to oscillate independently initially, but to subsequently become synchronized. ( 2001 Academic Press