Laboratory of Mathematical Physics, The Rockefeller University New York, NY, USA.
Front Physiol. 2011 Aug 1;2:46. doi: 10.3389/fphys.2011.00046. eCollection 2011.
Mean field models are often useful approximations to biological systems, but sometimes, they can yield misleading results. In this work, we compare mean field approaches with stochastic models of intracellular calcium release. In particular, we concentrate on calcium signals generated by the concerted opening of several clustered channels (calcium puffs). To this end we simulate calcium puffs numerically and then try to reproduce features of the resulting calcium distribution using mean field models were all the channels open and close simultaneously. We show that an unrealistic non-linear relationship between the current and the number of open channels is needed to reproduce the simulated puffs. Furthermore, a single channel current which is five times smaller than the one of the stochastic simulations is also needed. Our study sheds light on the importance of the stochastic kinetics of the calcium release channel activity to estimate the release fluxes.
均值场模型通常是生物系统的有用近似，但有时会产生误导性结果。在这项工作中，我们将均值场方法与细胞内钙释放的随机模型进行了比较。特别是，我们集中研究了由几个簇集通道（钙爆发）协同打开产生的钙信号。为此，我们对钙爆发进行了数值模拟，然后尝试使用同时打开和关闭所有通道的均值场模型来再现产生的钙分布的特征。我们表明，需要一种不现实的非线性关系来再现模拟爆发的电流与开放通道数量之间的关系。此外，还需要一个比随机模拟小五倍的单个通道电流。我们的研究强调了钙释放通道活动的随机动力学对估计释放通量的重要性。
