[Relation between disorders of erythrocyte membrane permeability for monovalent ions and intracellular distribution of calcium in primary arterial hypertension].

The relation of electric potential, lithium and potassium withdrawal rates and erythrocytic balance Na-Na exchange rate constant to intracellular calcium concentration was investigated. Intracellular calcium concentration was modified by means of Ca-ionophore A 23187 and Ca-EGTA buffer. Hypertensive patients showed no differences in erythrocyte membrane electric potential, as determined by chlorine distribution. Only two systems of univalent cations transport were shown to be dependent on the intracellular calcium concentration: calcium increase was accompanied by the opening of K+-channels and the inhibition of erythrocyte membrane Na-K-ATPase. Increased rate of calcium withdrawal from erythrocytes of patients with essential hypertension and spontaneously-hypertensive rats under the effect of Ca-ionophore and moderate Ca2+ concentrations was due to an insufficiency of the cell's Ca-pump rather than disorders in the properties of K+-channels. No significant calcium effect on passive transmembrane ion diffusion, Na, K-cotransport and Na--Na (Na--Li)-countertransport could be demonstrated.