REGULATION OF THE VOLUME OF HUMAN ERYTHRO CYTES - THE ROLE OF CALCIUM-ACTIVATED POTASSIUM CHANNELS

A mathematical model of stabilization of erythrocytes volume which tak es into account the homeostasis of univalent ions and the calcium regu lation of potassium floux through the membrane has been studied. The m odel has the only stable solution at all actual values of parameters. The investigation of the steady-state cell volume dependence on membra ne permeability for potassium and sodium ions has shown that volume is much better protected against a nonspecific change in permeability th an against a specific increase in the membrane permeability for potass ium or sodium ions. In the case of a nonspecific increase of the eryth rocyte membrane permeability for cations the cell volume has best stab ilization when the stochiometry of sodium and potassium ions transport ed by a Na,K-ATPase is 3/2.