Impaired cell volume regulation in taurine deficient cultured astrocytes.
Taurine concentration was reduced by 40 and 65%, respectively in rat cerebellar astrocytes grown in a chemically defined medium or in culture medium containing a blocker of taurine transport (GES). Cell volume in these taurine deficient cells was 10%-16% higher than in controls. When challenged by hyposmotic conditions, astrocytes release taurine and this efflux contributes to the volume regulatory decrease observed in these cells. Taurine deficient astrocytes showed a less efficient volume recovery as compared to controls with normal taurine levels. Exposed to 50% hyposmotic medium, astrocytes with normal taurine concentration recovered 60% of their original volume whereas taurine deficient cells recovered only 30-35%. Similarly, in 30% hyposmotic medium, taurine deficient astrocytes recovered only 40% as compared to 75% in controls. No compensatory increases in the efflux of other osmolytes (free amino acids or potassium) were observed during regulatory volume decrease in taurine deficient astrocytes.
Morán
J
J
Institute of Cell Physiology, National University of Mexico, Mexico City.
Maar
T E
TE
Pasantes-Morales
H
H
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000502:physiology*; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000502:physiology*; D003470:Culture Media; D007038:Hypotonic Solutions; D007700:Kinetics; D051381:Rats; D012413:Rubidium / Q000378:metabolism; D013654:Taurine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology
D000596:Amino Acids; D003470:Culture Media; D007038:Hypotonic Solutions; D013654:Taurine; C009558:taurocyamine; D012413:Rubidium