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Duration of expression of inducible nitric oxide synthase in glial cells
Author(s) -
Park S. K.,
Murphy S.
Publication year - 1994
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490390407
Subject(s) - nitric oxide synthase , nitric oxide , lipopolysaccharide , chemistry , beta (programming language) , messenger rna , microbiology and biotechnology , interferon gamma , astrocyte , endocrinology , medicine , biology , biochemistry , in vitro , central nervous system , gene , computer science , programming language
Lippolysaccharide (LPS) or a combination of interleukin (IL)‐1ß and interferon (IFN)‐γ cause transcriptional induction of a calcium‐independent nitric oxide synthase (NOS) in astrocytes and C6 glioma cells. LPS induction of NOS in C6 cells was evidenced by a small amount of nitrite accumulation as compared with cells exposed to IL‐1ß/IFN‐γ, but the maximal NOS activity achieved (as revealed by cGMP formation) was the same. The NOS activity induced by LPS in C6 cells was maximal at 4 to 8 hr and then rapidly decreased, while NOS activity induced by IL‐1ß/IFN‐γ slowly decreased after 4 hr. In addition, the effects of re‐presenting IL‐1ß/IFN‐γ to both astrocytes and C6 cells after maximal induction of activity of the inducible from of NOS were studied. The re‐addition of cytokines prolonged both NOS mRNA expression and also enzyme activity, suggesting effects at either the transcriptional (further induction) or translational level (mRNA stability). These results imply that the time course of NO production by induced astrocytes depends both upon the nature of the inducing stimulus and the frequency of the cells' exposure to it. © 1994 Wiley‐Liss, Inc.