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Possible involvement of tyrosine kinase activation in lipopolysaccharide‐induced expression of Ca 2+ ‐insensitive but calmodulin‐coupling nitric oxide synthase in rat glial cells
Author(s) -
Kitamura Y.,
Imaizumi R.,
Kitayama Y.,
Esumi H.,
Nomura Y.
Publication year - 1996
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/(sici)1097-4547(19960115)43:2<235::aid-jnr11>3.0.co;2-5
Subject(s) - nitric oxide synthase , cycloheximide , calmodulin , staurosporine , nitric oxide , lipopolysaccharide , chemistry , citrulline , microbiology and biotechnology , astrocyte , tyrosine kinase , protein kinase a , kinase , biochemistry , arginine , biology , endocrinology , signal transduction , enzyme , protein biosynthesis , amino acid , central nervous system
To clarify the properties of an inducible type of nitric oxide synthase (i‐NOS) in the brain, we examined whether lipopolysaccharide (LPS) induces NOS in glial cells cultured from neonatal rats. NOS activities (NO 2 − accumulation and L‐[ 14 C]citrulline formation) were detected by treatment with LPS at 10 μg/ml for 6–72 hr. L‐[ 14 C]citrulline formation by LPS‐induced i‐NOS was inhibited by N G ‐monomethyl‐L‐arginine (a NOS inhibitor) and diphenyleneiodonium (a flavo‐protein inhibitor). The activity was not markedly changed in the presence or absence of Ca 2+ . The induction of i‐NOS by LPS was abolished by cycloheximide, actinomycin D, or dexamethasone. In addition, the induction was inhibited by herbimycin A (a tyrosine kinase inhibitor), but was not by staurosporine, W‐7, or FK‐506. After LPS stimulation, 130 kDa proteins were reacted with anti‐rat liver i‐NOS antibody 5–72 hr. i‐NOS induced from glial cells coupled tightly with endogenous calmodulin (CaM) even in the absence of Ca 2+ . These results suggest that LPS induces expression of 130‐kDa i‐NOS through an activation of tyrosine kinase, after which i‐NOS couples with CaM, and that NO is formed for 6–72 hr in glial cells. © 1996 Wiley‐Liss, Inc.