title: Swelling-induced release of glutamate, aspartate, and taurine from astrocyte cultures.
abstract: Swelling of primary astrocyte cultures by exposing them to hypotonic media caused release of label after the cells had been allowed to accumulate 3H-L-glutamate, 3H-D-aspartate, or 3H-taurine. Comparable release of endogenous L-glutamate or taurine, as measured by high-pressure liquid chromatography (HPLC), was also found. Release of label was not affected by treating the cells with cytochalasin B, indicating that microfilament polymerization was not significantly involved. Hypotonic-induced release did not appear to principally involve reversal of the Na(+)-dependent uptake system since increasing external K+ to depolarize the cells by replacement of external Na+, thus maintaining isotonic conditions, increased release to a lesser extent. Threo beta-hydroxyaspartate, a potent 3H-L-glutamate uptake blocker, added externally stimulated efflux of 3H-L-glutamate independently of the swelling-induced efflux. Upon restoration of swollen cells to isotonic medium they showed an unimpaired ability to take up 3H-L-glutamate. The swelling-induced release of label was inhibited by a number of anion transport inhibitors, one of which has been shown to significantly improve outcome in an experimental brain trauma/hypoxia model in which astrocyte swelling is an early event.
authors.affiliation: Division of Neurosurgery, Albany Medical College, New York 12208.
authors.forename: H K
authors.initials: HK
authors.lastname: Kimelberg
authors.forename: S K
authors.initials: SK
authors.lastname: Goderie
authors.forename: S
authors.initials: S
authors.lastname: Higman
authors.forename: S
authors.initials: S
authors.lastname: Pang
authors.forename: R A
authors.initials: RA
authors.lastname: Waniewski
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D000838:Anions / Q000037:antagonists & inhibitors / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism*; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001692:Biological Transport; D002470:Cell Survival; D002478:Cells, Cultured; D003470:Culture Media; D003571:Cytochalasin B / Q000494:pharmacology; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D007038:Hypotonic Solutions / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013654:Taurine / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D000838:Anions; D003470:Culture Media; D005971:Glutamates; D007038:Hypotonic Solutions; D013654:Taurine; D001224:Aspartic Acid; D003571:Cytochalasin B; D018698:Glutamic Acid; D012964:Sodium