title: Acidic pH rapidly increases immunoreactivity of glial fibrillary acidic protein in cultured astrocytes.
abstract: Neuroepithelial progenitor cells from forebrains of newborn rat pups develop into "mature" astrocytes in an epidermal growth factor-containing medium free of serum (Von Visger et al: Exp Neurol 128:34, 1994). Eight-week-old "mature" astrocyte cultures on poly-L-lysine-coated dishes were exposed to an acidic medium (pH 5.8-6.0) for 2-6 h. Immunoreactivity for glial fibrillary acidic protein (GFAP) dramatically and rapidly increased; this immediate increase was not affected by pretreatment with cycloheximide. In further experiments we found that the increase in GFAP was undiminished for 24-48 h after the acid-treated astrocytes were returned to normal growth medium. The Ca2+ channel antagonists nifedipine and diltiazem attenuated the increase in GFAP immunoreactivity. These results suggest that extracellular acidosis may produce a rapid increase in GFAP immunoreactivity in astrocytes independent of de novo protein synthesis, possibly by increasing intracellular levels of free Ca2+ ions.
authors.affiliation: Department of Anatomy, University of Maryland School of Medicine, Baltimore 21201, USA.
authors.forename: T H
authors.initials: TH
authors.lastname: Oh
authors.forename: G J
authors.initials: GJ
authors.lastname: Markelonis
authors.forename: J R
authors.initials: JR
authors.lastname: Von Visger
authors.forename: B
authors.initials: B
authors.lastname: Baik
authors.forename: M T
authors.initials: MT
authors.lastname: Shipley
mesh_terms: D000138:Acidosis; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D009457:Neuroglia / Q000276:immunology / Q000378:metabolism; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002118:Calcium