title: Ion fluxes, transmembrane potential, and osmotic stabilization: a new dynamic electrophysiological model for eukaryotic cells.
abstract: 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.
authors.affiliation: 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. clair.poignard@inria.fr
authors.forename: Clair
authors.initials: C
authors.lastname: Poignard
authors.forename: Aude
authors.initials: A
authors.lastname: Silve
authors.forename: Frederic
authors.initials: F
authors.lastname: Campion
authors.forename: Lluis M
authors.initials: LM
authors.lastname: Mir
authors.forename: Olivier
authors.initials: O
authors.lastname: Saut
authors.forename: Laurent
authors.initials: L
authors.lastname: Schwartz
mesh_terms: D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000502:physiology; D048429:Cell Size; D006224:Cricetinae; D055724:Electrophysiological Phenomena; D005057:Eukaryotic Cells / Q000378:metabolism*; D005434:Flow Cytometry / Q000379:methods; D007477:Ions; D008564:Membrane Potentials / Q000502:physiology*; D008954:Models, Biological; D009994:Osmolar Concentration; D009995:Osmosis; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
chemical_list: D007477:Ions; D012964:Sodium; D011188:Potassium