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POTASSIUM EFFECTS ON ION TRANSPORT IN BRAIN SLICES
Author(s) -
Hertz L.
Publication year - 1968
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1968.tb06167.x
Subject(s) - potassium , efflux , sodium , chemistry , compartment (ship) , biophysics , extracellular , ion , glutamate receptor , stimulation , kinetics , biochemistry , inorganic chemistry , endocrinology , biology , organic chemistry , oceanography , receptor , physics , quantum mechanics , geology
—(1) Fluxes of sodium, potassium, chloride and glutamate ions were studied in brain slices by aid of radio‐isotopes. Desaturation curves showed the efflux to occur from at least two compartments with widely different kinetics. (2) The slowly exchanging component comprises from about 10 (sodium, potassium, chloride) to about 30 (glutamate) per cent of the radioactivity in the tissue. An energy‐requiring uptake of potassium and extrusion of sodium seems to occur in this compartment, which probably includes the nerve cells. (3) A rather slow efflux of especially potassium ions from the rapidly exchanging fraction indicates that this component may not be purely extracellular, but also seems to include cells, which possibly are neuroglial. The hypothesis of a cellular origin is supported by the demonstration of an increase in the rate constant of the potassium efflux evoked in the presence of oxygen by high concentrations of potassium. (4) Evidence is presented that the increase in the rate constant of the potassium efflux is due to a potassium‐induced stimulation of active transport. No coupling seems to occur between the stimulated potassium transport and movements of sodium, but potassium ions may be accompanied by glutamate ions.