• Toxicological Research
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• v.22 no.3
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• pp.245-251
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• 2006

Nitric oxide(nitrogen monoxide, NO) plays important physiological roles, but excessive generation can be toxic. NO is present in cigarette smoke at up to 1,000 ppm, and probably represents one of the greatest exogenous sources of NO to which humans are exposed. We investigated whether cigarette smoking reduces the production of endogenous NO and whether it influences the action of lipopolysaccharide(LPS) to induce nitric oxide synthase activity in mouse brain. Mice(C57BL6/J) were exposed to cigarette smoke for 8 weeks. LPS was injected intraperitoneally in single or combination with the exposure to cigarette smoke. Six hours after the injection of LPS, mice were sacrificed and sera and brains were collected. Serum concentrations of nitrate and nitrite were not charged by 4-week smoke exposure, but were significantly increased by 6 and 8 weeks of smoke exposure. Interestingly, cigarette smoke reduced the elevation in serum nitrate and nitrite concentrations produced by LPS after 4-week smoking exposure. NO synthase(NOS) activity in brain was upregulated by LPS-administration. However, cigarette smoke exposure remarkably and consistently decreased the LPS-induced activity in mouse brain. This result suggests that cigarette smoking may affect against overproduction of the endogenous NO by LPS through the inhibition of NOS activity induced by LPS in brain or by modulation of the LPS action for the induction of NOS activity. We also suggest the possibility that the exogenous NO evolved in cigarette smoke enables feedback inhibition of NOS activity or other possibility that it attenuates the toxicity of endotoxin LPS in vivo by unknown mechanisms, which should be further studied.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.170-175
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• 2007

Activated microglia by neuronal injury or inflammatory stimulation overproduce nitric oxide (NO) by inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) such as superoxide anion, resulting in neurodegenerative diseases. The toxic peroxynitrite (ONOO$^-$), the reaction product of NO and superoxide anion further contributes to oxidative neurotoxicity. We tried to evaluate the effects of two kinds of varieties of Perilla frutescens var japnica Hara on the NO production in lipopolysaccharide (LPS)-activated microglia. The perilla cultivars of Namcheondeulkkae (NC) and Boradeulkkae (BR) were developed by pure line from the local variety and by a cross between 'deulkkae' and 'chajogi', respectively. Spirit, hexane, chloroform and butanol fractions of the leaves of NC and BR inhibited the production of NO in LPS-activated microglia. The fractions of BR showed stronger activity than NC and the spirit extracts was the most potent in both cultivars. The solvent fractions of BR suppressed the expression of protein and mRNA of iNOS in LPS-activated microglial cells. Moreover, the extracts of NC and BR showed the activity of peroxynitrite scavenging in cell free bioassay system. These results imply that Namcheondeulkkae and Boradeulkkae might have neuroprotective activity through the inhibition of NO production by activated microglial cells and peroxynitrite scavenging activity.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.315-321
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• 1999

Since it has been known that hypoxia increases inducible nitric oxide synthase (iNOS) gene expression through hypoxia responsive element, it was possible to establish the hypothesis that nitric oxide could be a mediator of hypoxia to inhibit Cyplal promoter activity. In order to test this hypothesis, we have undertaken the study to examine the effects of hypoxia and nitric oxide on Cyplal promoter activity in Hepa I cells. Mouse Cyplal 5'flanking DNA, 1.6 Kb was cloned into pGL3 expression vector in order to construct pmCyplal-Luc. Hepa I cells were transfected with pmCyplal-Luc and were treated with $10^{-9}$ M TCDD and nitric oxide producing agents, such as lipopolysaccharide(LPS), sodium nitroprusside (SNP). Luciferase activity of reporter gene was measured from pmCyplal-Luc transfected Hepa I cell lysate which contains 2 g total protein using luciferin as a substrate. Nitric oxide producing agents, such as lipopolysaccharide (LPS), sodium nitroprusside(SNP) showed inhibition of luciferase activity that was induced by $10^{-9}$M TCDD treatment with dose dependent manner. Concomitant treatment of 1mM $N^G$-nitro-ι-arginine with $10^{-6}$~$10^{-4}$M sodium nitro-prusside recovered luciferase activity from the TCDD induced luciferase activity that was inhibited by nitric oxide producing agents. These demonstrated that nitric oxide could be a mediator of inhibitors on dioxin induced Cyplal expression in Hepa I cells.

• The Journal of Internal Korean Medicine
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• v.22 no.1
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• pp.53-61
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• 2001

Objectives : The following are the results of the experimental studies of Samjasan (SJS) extract on the nitric oxide synthase (NOS) activity and the level of lipid peroxide in the penises of rats. Methods : Cnidii Fructus, Cuscutae Semen, Schizandrae Fructus constitute SJS. 150 g of crushed crude drug was extracted with methyl alcohol, under reflux, for 24 hours, three times; the total extractive was evaporated under reduced pressure to give 28.6 g. Results : In vitro, the SJS extract didn't effect the activity of NOS. However, the SJS extract decreased the activities, the ratio of type conversion of xanthine oxidase, the levels of lipid peroxide, In vitro, after administration of the SJS extract to rats, the activities and ratio of type conversion of xanthine oxidase decreased, but the activity of NOS and the content of nitrite increased. Also, the levels of the superoxide anion radical and lipid peroxide decreased in the penises of rats. But, after administration of the SJS extract to rats, the levels of glutathione did not increase. The effects of the SJS extract did better as the dosage and the length of treatment increased. Conclusions : These results suggest that the SJS extract decreases the activities of free radical generating enzymes which form lipid peroxide and increases the NOS activity in the penises of rats. Therefore, the SJS extract is capable of improving of sexual ability in rats.

• Natural Product Sciences
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• v.10 no.1
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• pp.1-10
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• 2004

Plant flavonoids possess anti-inflammatory activity in vitro and in vivo. Although the action mechanisms are not fully understood, recent studies have clearly shown that certain flavonoids, especially flavone derivatives, express their anti-inflammatory activity at least in part by modulation of proinflammatory gene expression such as cyclooxygenase-2, inducible nitric oxide synthase and various cytokines. This review summarizes the recent findings of flavonoids modulating expression of proinflammatory molecules.

• BMB Reports
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• v.41 no.1
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• pp.79-85
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• 2008

The source of nitric oxide (NO) in plants is unclear and it has been reported NO can be produced by nitric oxide synthase (NOS) like enzymes and by nitrate reductase (NR). Here we used wild-type, Atnos1 mutant and nia1, nia2 NR-deficient mutant plants of Arabidopsis thaliana to investigate the potential source of NO production in response to Verticillium dahliae toxins (VD-toxins). The results revealed that NO production is much higher in wild-type and Atnos1 mutant than in nia1, nia2 NR-deficient mutants. The NR inhibitor had a significant effect on VD-toxins-induced NO production; whereas NOS inhibitor had a slight effect. NR activity was significantly implicated in NO production. The results indicated that as NO was induced in response to VD-toxins in Arabidopsis, the major source was the NR pathway. The production of NOS-system appeared to be secondary.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.155-159
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• 2006

Among the Shc proteins, p66shc is known to be related to oxidative stress responses and regulation of the production of reactive oxygen species (ROS). The present study was undertaken to investigate the role of p66shc on endothelial nitric oxide synthase (eNOS) activity in the mouse embryonic fibroblasts (MEFs). When wild type (WT) or p66shc (-/-) MEFs were transfected with full length of eNOS cDNA, the expression and activity of eNOS protein were higher in the p66shc (-/-) MEFs. These phenomena were reversed by reconstitution of p66shc cDNA transfection in the p66shc (-/-) MEFs. The basal superoxide production in the p66shc (-/-) MEFs was not significantly different from that of WT of MEFs. However, superoxide production induced by NADPH in the p66shc (-/-) MEF was lesser than that in WT MEFs. When compared with WT MEFs, cell lysate of p66shc (-/-) MEFs showed significantly increased H-ras activity without change of endogenous H-ras expression. Our findings suggest the pivotal role of p66shc adaptor protein played in inhibition of endothelial nitric oxide production via modulation of the expression and/or activity of eNOS protein.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.337-341
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• 2006

The present study was designed to investigate the protein expression of nitric oxide synthase (NOS) and guanylyl cyclase (GC) activity in ischemia/perfusion (I/R) renal injury in rats. Renal I/R injury was experimentally induced by clamping the both renal pedicle for 40 min in Sprague-Dawley male rats. The renal expression of NOS isoforms was determined by Western blot analysis, and the activity of guanylyl cyclase was determined by the amount of guanosine 3', 5'-cyclic monophosphate (cGMP) formed in response to sodium nitroprusside (SNP), NO donor. I/R injury resulted in renal failure associated with decreased urine osmolality. The expression of inducible NOS (iNOS) was increased in I/R injury rats compared with controls, while endothelial NOS (eNOS) and neuronal NOS (nNOS) expression was decreased. The urinary excretion of NO metabolites was decreased in I/R injury rats. The cGMP production provoked by SNP was decreased in the papilla, but not in glomerulus. These results indicate an altered regulation of NOS expression and guanylyl cyclase activity in I/R-induced nephropathy.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.832-839
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• 2003

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and produce excessive amounts of nitric oxide (NO) and prostaglandin E$_2$ (PGE$_2$), which play key roles in the processes of inflammation and carcinogenesis. The root of Paeonia lactiflora Pall., and the root cortex of Paeonia suffruticosa Andr., are important Chinese crude drugs used in many traditional prescriptions. 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose (PGG) is a major bioactive constituent of both crude drugs. PGG has been shown to possess potent anti-oxidant, anti-mutagenic, anti-proliferative and anti-invasive effects. In this study, we examined the inhibitory effects of 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose (PGG) isolated from the root of Paeonia lactiflora Pall. on the COX-2 and iNOS activity in LPS-activated Raw 264.7 cells, COX-1 in HEL cells. To investigate the structure-activity relationships of gallate and gallic acid for the inhibition of iNOS and COX-2 activity, we also examined (-)-epigallocatechin gallate (EGCG), gallic acid, and gallacetophenone. The results of the present study indicated that PGG, EGCG, and gallacetophenone treatment except gallic acid significantly inhibited LPS-induced NO production in LPS-activated macrophages. All of the four compounds significantly inhibited COX-2 activity in LPS-activated macrophages. Among the four compounds examined, PGG revealed the most potent in both iNOS ($IC_{50}$ = 18 $\mu\textrm{g}/mL$) and COX-2 inhibitory activity (PGE$_2$: $IC_{50}$ = 8 $\mu\textrm{g}/mL$ and PGD$_2$: $IC_{50}$ = 12 $\mu\textrm{g}/mL$), respectively. Although further studies are needed to elucidate the molecular mechanisms and structure-activity relationship by which PGG exerts its inhibitory actions, our results suggest that PGG might be a candidate for developing anti-inflammatory and cancer chemopreventive agents.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.3
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• pp.680-684
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• 2006

This study was designed to investigate effects of KH-304 in improving erectile dysfunction (ED), particularly in terms of nitric oxide (NO)-cGMP pathways. After oral administration of the KH-304 water extract, 1OOmg, 300mg, 500mg or 700mg per 1 kg of Dody weigh for 10days, We examined the expression and activity of two enzyme: neuronal NO synthase (nNOS), endothelial NO synthase (eNOS) and that act upon the major NO-cGMP signaling pathway in penile tissue. Effect of KH-304 on COMP degradation was also examined using bovine vascular smooth muscle cells pretreated with an NO donor, S-nitroso-N-Acetylpenicillamine (SNAP), Also, it examined the endothelial NO synthase (eNOS) for seaching effecting period (100mg, 300mg/kg for 10 and 30days) and peak intracavernous pressures (ICPS) in penile tissues rabbit copus cavernosum contracted by 10-6 M phenylephrine. The severely reduced peak intracavernous pressures (ICPS) in penile tissues were restored completely after KH-304 treatment, and KH-304 treatment significantly made the latency period earlier. Furthermore, the penile expression levels of nNOS, eNOS dependent NOS activities and COMP concentrations were increased significantly in the KH-304 100, 300mg treated rats. These results suggest that KH-304 with high expression of NOS may be useful in erectile dysfunction.