Premium
Stimulation of Na + /Mg 2+ antiport in rat erythrocytes by intracellular Cl −
Author(s) -
Ebel H.,
Günther T.
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00417-4
Subject(s) - antiporter , intracellular , extracellular , chemistry , efflux , ion transporter , membrane transport , stimulation , intracellular ph , biophysics , biochemistry , membrane , biology , endocrinology
Mg 2+ efflux from rat erythrocytes was measured in NaCl, NaNO 3 , NaSCN and Na gluconate medium. Substitution of extracellular and intracellular Cl − with the permeant anions NO 3 − and SCN − reduced Mg 2+ efflux via Na + /Mg 2+ antiport. After substitution of extracellular Cl − with the non‐permeant anion gluconate, Mg 2+ efflux was not significantly reduced. In Na gluconate medium, an influence of the changed membrane potential and intracellular pH on Mg 2+ efflux could be excluded. The results indicate the existence of Cl − ‐independent Na + /Mg 2+ antiport and of Na + /Mg 2+ antiport stimulated by intracellular Cl − . Intracellular Cl − , as determined by means of 36 Cl − , was found to stimulate Na + /Mg 2+ antiport through a cooperative effect according to a sigmoidal kinetics. The Hill coefficient for intracellular Cl − amounted to 1.4–1.8, indicating that two intracellular Cl − may be simultaneously active. With respect to specificity, Cl − was most effective, followed by Br − , J − , and F − . Stimulation of Na + /Mg 2+ antiport by intracellular Cl − together with intracellular Mg 2+ may play a role during deoxygenation of erythrocytes and in essential hypertension.