Investigations on the control of ion transport in human erythrocytes. I. Passive 86Rb efflux and possibilities of its influence.

In isotonic solutions of low NaCl concentration, human erythrocytes exhibit a strong increase of the rate constant of passive Rb+ efflux. In this range of low ionic strength the Rb+ efflux is reduced by preincubation of erythrocytes with neuraminidase, by treatment of erythrocytes with nystatin or by reduction of temperature. All these factors do not have any influence on the rate constant in solutions of physiological NaCl concentration. Ouabain (10-4 M) influences Rb+ efflux neither at low nor at physiological NaCl concentration. The results are interpreted with regard to a possible control of Rb+ efflux by surface potential and transmembrane potential.