Modeling cell volume regulation in nonexcitable cells: the roles of the Na⁺ pump and of cotransport systems

Abstract

The purpose of this study is to contribute to understanding the role of Na+-K+-ATPase and of ionic cotransporters in the regulation of cell volume, by employing a model that describes the rates of change of the intracellular concentrations of Na+, K+, and Cl−, of the cell volume, and of the membrane potential. In most previous models of dynamic cellular phenomena, Na+-K+-ATPase is incorporated via phenomenological formulations; the enzyme is incorporated here via an explicit kinetic scheme. Another feature of the present model is the capability to perform short-term cell volume regulation mediated by cotransporters of KCl and NaCl. The model is employed to perform numerical simulations for a “typical” nonpolarized animal cell. Basically, the results are consistent with the view that the Na+ pump mainly plays a long-term role in the maintenance of the electrochemical gradients of Na+ and K+ and that short-term cell volume regulation is achieved via passive transport, exemplified in this case by the cotransport of KCl and NaCl.

A possible role for membrane depolarization in epithelial wound healing

“…This is consistent with our previous observations that the nonspecific membrane depolarization of confluent BCE cells and other epithelia in culture elicits a characteristic reorganization of the actin cytoskeleton (13). Hence, the findings of the present study further support the idea, suggested by several authors (13,23,29,42), that the PMP of nonexcitable cells may play a role in the regulation of diverse cellular processes.…”

“…The cellular electrical findings reported here might possibly be related to the generation of macroscopic transtissular electrical fields in the course of epithelial wound healing (see above), but the nature of this relationship is not analyzed in this work. The results reported here support the idea suggested previously by several authors (13,23,29,42) that the PMP of nonexcitable cells may play a role as an intermediary of diverse cellular signaling processes.…”

Quantitative estimation of transmembrane ion transport in rat renal collecting duct principal cells

“…These models were first introduced by Tosteson and Hoffman (Tosteson and Hoffman 1960). Subsequent development of such models was described by several authors (Jakobsson 1980; Hernandez and Cristina 1998;Fraser and Huang 2004). Various models of this type differ by the equations that govern transmembrane ion fluxes, and by the number of intracellular osmolytes and mechanisms of transmembrane transport considered (Keener and Sneyd 1998).…”

Monitoring the dielectric response of single cells following mitochondrial adenosine triphosphate synthase inhibition by oligomycin using a dielectrophoretic cytometer

“…For example, the metabolic state is an important factor in controlling ion homeostasis and hence cytoplasm conductivity. [13][14][15] Hence determining dielectric effects due to perturbations of cell metabolic state is important for many applications of DEP.…”