Intracellular ion changes of astrocytes in response to extracellular potassium

✍ Scribed by Dr. W. Walz; L. Hertz

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 723 KB
• Volume: 10
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490100408

✦ Synopsis

Intracellular changes of K f , Na', and Cl-were investigated by the aid of radiotracers in primary cultures of astrocytes when extracellular K f 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 Kf contcnt increased by 50% within seconds, and it doubled within 1-2 min. The increase must be carrier mediated, because keeping the K X C1 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 correspondcd only to 10% of thc accumulatcd K+. When K + was increased to 54 mM, the Na+ content increased transiently. C1-increased by about 1525% 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 ohervations, it is necessary to postulate endogenous production of an anion and of H + , which in turn is partly exchanged with Na'