Carrier-mediated KCl accumulation accompanied by water movements is involved in the control of physiological K+ levels by astrocytes.
Potassium accumulation and water transport into mouse astrocytes in primary cultures were investigated when external potassium was increased from 3 to 12 mM. The intracellular potassium content increased by 63% within 50 s of such a change. The increase consisted of a ouabain- and furosemide-sensitive component, both contributing in about the same amounts. Experiments with altered ion composition revealed that the furosemide-sensitive component consisted of a KCl accumulation. Water moved into the astrocytes without delay after such an external K+ increase and increased the cell water by 27%. This water increase was abolished in solutions with reduced Cl- and during application of furosemide. Thus, these results on a KCl uptake accompanied by water movements into astrocytes suggest a potential mechanism by which glial cells in situ can regulate external K+ levels.
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism*; D002352:Carrier Proteins / Q000502:physiology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D005665:Furosemide / Q000494:pharmacology; D051379:Mice; D010042:Ouabain / Q000494:pharmacology; D011189:Potassium Chloride / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
D002352:Carrier Proteins; D014867:Water; D010042:Ouabain; D011189:Potassium Chloride; D005665:Furosemide