Inhibition of volume regulation and efflux of osmoregulatory amino acids by blockers of Cl- transport in cultured astrocytes.
Regulatory volume decrease (RVD) in astrocytes was inhibited by the Cl- exchanger blockers 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), dipyridamole and niflumic acid but not by the Cl- channel inhibitors diphenylamine-2-carboxylate (DPC) and anthracene-9-carboxylate (9-AC). The volume activated efflux of [3H]taurine and [3H]D-aspartate (as marker for glutamate) was similarly affected by these compounds. However, neither RVD nor osmolyte fluxes were significantly reduced by removal of external Cl-, suggesting that an anion exchanger activity is not required for the volume regulatory process. Alternatively, these results suggest that the anion exchanger molecule may function as an unidirectional Cl- channel possibly permeable also to amino acids.
Sánchez-Olea
R
R
Institute of Cell Physiology, National University of Mexico, Mexico City.
Peña
C
C
Morán
J
J
Pasantes-Morales
H
H
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology; D002712:Chlorides / Q000378:metabolism*; D004176:Dipyridamole / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D009544:Niflumic Acid / Q000494:pharmacology*; D051381:Rats; D013654:Taurine / Q000378:metabolism*; D014316:Tritium; D014882:Water-Electrolyte Balance / Q000187:drug effects
D018118:Chloride Channels; D002712:Chlorides; D014316:Tritium; D013654:Taurine; D001224:Aspartic Acid; D009544:Niflumic Acid; D004176:Dipyridamole; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid