Mean field strategies induce unrealistic non-linearities in calcium puffs

G. SOLOVEY; D FRAIMAN; S. PONCE DAWSON

Frontiers in Physiology

Frontiers

Año: 2011 vol. 2 p. 1 - 11

1664-042X

Mean field models are often useful approximations to biological systems, but sometimes, theycan yield misleading results. In this work, we compare mean field approaches with stochasticmodels of intracellular calcium release. In particular, we concentrate on calcium signals generatedby the concerted opening of several clustered channels (calcium puffs). To this end we simulatecalcium puffs numerically and then try to reproduce features of the resulting calcium distributionusing mean field models were all the channels open and close simultaneously. We show thatan unrealistic non-linear relationship between the current and the number of open channels isneeded to reproduce the simulated puffs. Furthermore, a single channel current which is fivetimes smaller than the one of the stochastic simulations is also needed. Our study sheds lighton the importance of the stochastic kinetics of the calcium release channel activity to estimatethe release fluxes.