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Dexamethasone Up‐Regulates a Constitutive Nitric Oxide Synthase in Cerebellar Astrocytes but Not in Granule Cells in Culture
Author(s) -
Baltrons Maria Antonia,
Agulló Luis,
García Agustina
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.64010447.x
Subject(s) - granule (geology) , nitric oxide synthase , dexamethasone , neuroscience , chemistry , microbiology and biotechnology , nitric oxide , biology , endocrinology , paleontology
Treatment of rat cerebellar astrocyte‐enriched primary cultures with dexamethasone enhances the nitric oxide‐dependent cyclic GMP formation induced by noradrenaline in a time‐(>6 h) and concentration‐dependent manner (half‐maximal effect at 1 n M ). Stimulation of cyclic GMP formation by the calcium ionophore A23187 is similarly enhanced. In contrast, cyclic GMP accumulation in cells treated with lipopolysaccharide is inhibited by dexamethasone. The potentiating effect of dexamethasone is prevented by the protein synthesis inhibitor cycloheximide and is not due to increased soluble guanylate cyclase activity. Agonist stimulation of [ 3 H]arginine to [ 3 H]citrulline conversion is enhanced by dexamethasone in astrocytes but not in cerebellar granule cells. These results indicate that glucocorticoids may up‐regulate astroglial calcium‐dependent nitric oxide synthase while preventing expression of inducible nitric oxide synthase and are the first report of a differential long‐term regulation of the expression of neuronal and astroglial constitutive nitric oxide synthase activities.