title: Dexamethasone augments ischemia-induced extracellular accumulation of glutamate in gerbil hippocampus.
abstract: Glucocorticoids exacerbate neuronal damage due to hypoxia, ischemia, seizure and hypoglycemia. Because the release of glutamate is closely involved in neuronal damage, the effects of dexamethasone on the ischemia-induced accumulation of extracellular amino acids (aspartate, glutamate, and glycine) were investigated in the gerbil hippocampal CA1 region by a microdialysis-high-performance liquid chromatography procedure in vivo. There were no differences in the extracellular concentrations of amino acids before ischemia between the control group and the dexamethasone (3m microg, i.c.v.)-injected group. The concentration of glutamate reached 246% of that before ischemia within 2.5 min of transient forebrain ischemia. Dexamethasone augmented the increase in glutamate to 508% of that before ischemia. This finding suggests that glucocorticoids aggravate ischemic neuronal damage by causing glutamate to accumulate in the extracellular space.
authors.affiliation: Department of Anesthesiology and Resuscitology, Ehime University School of Medicine, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: N
authors.initials: N
authors.lastname: Adachi
authors.forename: S
authors.initials: S
authors.lastname: Tsubota
authors.forename: T
authors.initials: T
authors.lastname: Nagaro
authors.forename: T
authors.initials: T
authors.lastname: Arai
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000633:toxicity*; D004195:Disease Models, Animal; D005110:Extracellular Space / Q000378:metabolism; D005849:Gerbillinae; D005938:Glucocorticoids / Q000633:toxicity*; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000378:metabolism*; D008297:Male; D016548:Prosencephalon / Q000098:blood supply*
chemical_list: D005938:Glucocorticoids; D018698:Glutamic Acid; D003907:Dexamethasone