Modeling cell volume regulation in nonexcitable cells: the roles of the Na+ pump and of cotransport systems.
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.
Hernández
J A
JA
Sección Biofísica, Facultad de Ciencias, Universidad de la República, 11400 Montevideo, Uruguay.
Cristina
E
E
D002352:Carrier Proteins / Q000378:metabolism*; D002468:Cell Physiological Phenomena; D016764:Cell Polarity; D002712:Chlorides / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D008962:Models, Theoretical; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D028021:Sodium-Potassium-Chloride Symporters; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D002352:Carrier Proteins; D002712:Chlorides; D028021:Sodium-Potassium-Chloride Symporters; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium