INRIA Bordeaux-Sud Ouest Team research MC2, Institut Mathématiques de Bordeaux, UMR CNRS 5251 (Applied Mathematics), 351 Cours de la Libération, 33405 Talence Cedex, France.
Eur Biophys J. 2011 Mar;40(3):235-46. doi: 10.1007/s00249-010-0641-8. Epub 2010 Nov 16.
Survival of mammalian cells is achieved by tight control of cell volume, while transmembrane potential has been known to control many cellular functions since the seminal work of Hodgkin and Huxley. Regulation of cell volume and transmembrane potential have a wide range of implications in physiology, from neurological and cardiac disorders to cancer and muscle fatigue. Therefore, understanding the relationship between transmembrane potential, ion fluxes, and cell volume regulation has become of great interest. In this paper we derive a system of differential equations that links transmembrane potential, ionic concentrations, and cell volume. In particular, we describe the dynamics of the cell within a few seconds after an osmotic stress, which cannot be done by the previous models in which either cell volume was constant or osmotic regulation instantaneous. This new model demonstrates that both membrane potential and cell volume stabilization occur within tens of seconds of changes in extracellular osmotic pressure. When the extracellular osmotic pressure is constant, the cell volume varies as a function of transmembrane potential and ion fluxes, thus providing an implicit link between transmembrane potential and cell volume. Experimental data provide results that corroborate the numerical simulations of the model in terms of time-related changes in cell volume and dynamics of the phenomena. This paper can be seen as a generalization of previous electrophysiological results, since under restrictive conditions they can be derived from our model.
哺乳动物细胞的存活是通过严格控制细胞体积来实现的，而自从 Hodgkin 和 Huxley 的开创性工作以来，跨膜电位已经被证明可以控制许多细胞功能。细胞体积和跨膜电位的调节在生理学中有广泛的意义，从神经和心脏疾病到癌症和肌肉疲劳。因此，了解跨膜电位、离子通量和细胞体积调节之间的关系变得非常重要。在本文中，我们推导出了一个将跨膜电位、离子浓度和细胞体积联系起来的微分方程组。特别是，我们描述了细胞在渗透胁迫后几秒钟内的动力学，这是以前的模型无法做到的，以前的模型要么假设细胞体积恒定，要么假设渗透调节是瞬时的。这个新模型表明，在细胞外渗透压变化后的几十秒内，膜电位和细胞体积的稳定都会发生。当细胞外渗透压恒定时，细胞体积随跨膜电位和离子通量的变化而变化，从而在跨膜电位和细胞体积之间提供了一个隐含的联系。实验数据提供的结果与模型的数值模拟在细胞体积和现象动力学方面的时间相关变化方面相吻合。本文可以被视为对以前电生理结果的推广，因为在限制条件下，它们可以从我们的模型中推导出来。
