Hemolytic properties of Ca(2+)-treated human erythrocytes under hydrostatic pressure

The effect of intracellular Ca2+ on high pressure-induced hemolysis of human erythrocytes was examined. Red cells were incubated with Ca2+ (0.01-1 mM) in the presence of ionophore A23187. The Ca(2+)-loaded cells were subjected to a pressure of 200 mPa. Treatment with 0.1 mM Ca2+ had the greatest suppressive effect on the hemolysis. On removal of intracellular Ca2+, red cells showed a morphological change from echinocytes to normal discocytes but the hemolysis remained unaltered. Measurement of intracellular K+ and viscosity demonstrated that the suppressive effect of Ca2+ on the hemolysis is irreversible and is largely associated with the increase of intracellular viscosity induced by K+ efflux.