Abstract |
Nitric oxide (NO) is thought to be a mediator in many of the processes of malignant brain tumor progression. We examined NO production in the brain of normal conscious, freely moving rats with or without implanted C6 glioma. Both nitrite (NO(2)(-)) and nitrate (NO(3)(-)) in the dialysates of the two groups were measured using an in vivo microdialysis technique. The mean concentration of NO(2)(-) in the glioma group was two-times higher than that in the control group (P<0.01). Concentrations of both NO(2)(-) and NO(3)(-) in the glioma and control groups decreased following intraperitoneal injection of N(G)-nitro-L-arginine methyl ester ( L-NAME), a non-selective inhibitor of NO synthase (NOS). NO production was also significantly suppressed in the glioma group, but not the control group, by intraperitoneal injection of 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), a selective inhibitor of inducible NOS (iNOS). On immunohistochemical examination, diffuse iNOS-positive cells were located within glioma tissue. ED1-positive cells (microglia/macrophages) were intermingled between glioma cells on double immunostaining. These results indicate that the basal level of NO production in the glioma group is higher than that in the control group and that the increased NO production was continuously induced by iNOS-expressing cells in glioma.
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Authors | Tatsuki Oyoshi, Masahiro Nomoto, Hirofumi Hirano, Jun-Ichi Kuratsu |
Journal | Journal of pharmacological sciences
(J Pharmacol Sci)
Vol. 91
Issue 1
Pg. 15-22
(Jan 2003)
ISSN: 1347-8613 [Print] Japan |
PMID | 12686726
(Publication Type: Journal Article)
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Chemical References |
- 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine
- Enzyme Inhibitors
- Thiazines
- Nitric Oxide
- Nitric Oxide Synthase
- Nitric Oxide Synthase Type II
- Nos2 protein, rat
- NG-Nitroarginine Methyl Ester
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Topics |
- Animals
- Brain Neoplasms
(enzymology, metabolism)
- Enzyme Inhibitors
(pharmacology)
- Glioma
(enzymology, metabolism)
- Half-Life
- Immunohistochemistry
- Male
- Microdialysis
- NG-Nitroarginine Methyl Ester
(pharmacology)
- Nitric Oxide
(biosynthesis)
- Nitric Oxide Synthase
(antagonists & inhibitors, biosynthesis)
- Nitric Oxide Synthase Type II
- Paraffin Embedding
- Rats
- Rats, Wistar
- Thiazines
(pharmacology)
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