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Intracellular ion changes of astrocytes in response to extracellular potassium
Author(s) -
Walz W.,
Hertz L.
Publication year - 1983
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490100408
Subject(s) - extracellular , intracellular , chemistry , potassium , biophysics , ion , endogeny , extracellular fluid , biochemistry , biology , organic chemistry
Abstract Intracellular changes of K + , Na + , and Cl − were investigated by the aid of radiotracers in primary cultures of astrocytes when extracellular K + was (1) increased from 3 to 12 mM and subsequently again decreased to 3 mM; and (2) increased from 5.4 to 54 mM with subsequent decrease to 5.4 mM. In both situations the K + content increased by 50% within seconds, and it doubled within 1‐2 min. The increase must be carrier mediated, because keeping the K x Cl product (Donnan equilibrium) constant did not lower the K + accumulation rates. The Na + content decreased when K + was increased to 12 mM, but the decrease corresponded only to 10% of the accumulated K + . When K + was increased to 54 mM, the Na + content increased transiently. Cl − increased by about 15‐25% of the accumulated K + . Return of extracellular K + to original levels evoked a very fast K + release, reversing all ion changes. The Na + content increased transiently during the release process. For an interpretation of these observations, it is necessary to postulate endogenous production of an anion and of H + , which in turn is partly exchanged with Na + .