Stochastic model of IP3-induced Ca2+ spiking of HEK293 cells.

Mathematical theory that accounts for the stochastic character of spike sequences of IP3-induced Ca2+ signalling calculates the probability distributions of the features of the [Ca2+]i time course, their moments and correlations. Including slow feedback from [Ca2+]i to components of the pathway poses a challenge to stochastic modelling. Here, we present a stochastic model that takes this feedback into account, allows for a non-linear dependency of the open probability of the Inositol 1,4,5-trisphosphate receptor channel (IP3R) on the feedback variable and the inclusion of more than one feedback with different relaxation time scales.