The logic of ionic homeostasis: Cations are for voltage, but not for volume - Fig 2

Intracellular ionic concentrations (A, B), cell volume (C), and intracellular osmolarity (D) at various levels of transmembrane water permeability. A: Changes of the [Na+]i, [Cl-]i, and [An-]i after opening of gNa and gCl when the time constant of water-dependent volume adjustment is 1 minute. B: The same when the time constant of water-dependent volume adjustment is 1 hour. C: Changes of the cell volume (in % of original volume) at various levels of transmembrane water permeability; to the right of each line—the time constant of water-dependent volume adjustment; the dashed line corresponding to a time constant of 1 second practically overlaps the thin line for the idealization when water-dependent adjustment of cell volume is instantaneous (time constant = 0). D: Changes in intracellular osmolarity at various levels of transmembrane water permeability; to the right of each line—the time constant of water-dependent volume adjustment; the time constant of infinity (∞) corresponds to the case when the membrane is not permeable to water. Initial conditions: [Na+]o = [Na+]i = 150 mM; [Cl-]o = 150 mM; [Cl-]i = 15 mM; [An-]i = 135 mM; z = -1; gNa = gCl = 0. Changes at time = 0: gNa = gCl = 1010 ions/(sec*V).