• Title, Summary, Keyword: nitric oxide (NO)

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NITRIC OXIDE AND DENTAL PULP (NITRIC OXIDE와 치수)

  • Kim, Young-Kyung;Kim, Sung-Kyo
    • Restorative Dentistry and Endodontics
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    • v.27 no.5
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    • pp.543-551
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    • 2002
  • Nitric oxide (NO) is a small molecule (mol. wt. 30 Da) and oxidative free radical. It is uncharged and can therefore diffuse freely within and between cells across membrane. Such characteristics make it a biologically important messenger in physiologic processes such as neurotransmission and the control of vascular tone. NO is also highly toxic and is known to acts as a mediator of cytotoxicity during host defense. NO is synthesized by nitric oxide synthase (NOS) through L-arginine/nitric oxide pathway which is a dioxygenation process. NO synthesis involves several participants, three co-substrates, five electrons, five co-factors and two prosthetic groups. Under normal condition, low levels of NO are synthesized by type I and III NOS for a short period of time and mediates many physiologic processes. Under condition of oxidant stress, high levels of NO are synthesized by type II NOS and inhibits a variety of metabolic processes and can also cause direct damage to DNA. Such interaction result in cytostasis, energy depletion and ultimately cell death. NO has the potential to interact with a variety of intercellular targets producing diverse array of metabolic effects. It is known that NO is involved in hemodynamic regulation, neurogenic inflammation, re-innervation, management of dentin hypersensitivity on teeth. Under basal condition of pulpal blood flow, NO provides constant vasodilator tone acting against sympathetic vasoconstriction. Substance P, a well known vasodilator, was reported to be mediated partly by NO, while calcitonin-gene related peptide has provided no evidence of its relation with NO. This review describes the roles of NO in dental pulp in addition to the known general roles of it.

Effect of Ginsenoside on Basal and Nitro-L-Arginine Suppressed Nitric Oxide Production in Rat Kidney

  • Kim, Hye-Young;Han, Sang-Won
    • Biomolecules & Therapeutics
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    • v.2 no.2
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    • pp.131-135
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    • 1994
  • The effect of ginsenoside (GS) from Panax ginseng on basal and nitro-L-arginine suppressed nitric oxide (NO) production was studied in rat kidney. NO production was determined by conversion to [$^{14C}$]=L-citrulline from [$^{14C}$]-L-arginine both in whole kidney and three renal segments; glomerulus, cortex excluding glomerulus (cortex-) and medulla. Nitro-L-arginine (total dose of 30 mg/kg/3 days, i.p.) significantly reduced NO production in whole kidney, which was prevented by GS pretreatment (30 mg/kg/3 days, i.p.). Relative high dose of GS (120 mg/kg/4 days, i.p..) selectively increased NO production in glomerulus and cortex-. Protein content, on wet weight basis, in cortex- and glomerular DNA content were significantly reduced by GS. Our results confirm the existence of constitutive nitric oxide synthase in kidney and it seems that target nephron segment for volume expansion due to GS'NO-mediated vasodilation and for NO production stimulated by GS is cortex including glomerulus.lus.

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Inhibitory Activity of Chinese Medicinal Plants on Nitric Oxide Synthesis in Lipopolysaccharide -Activated Macrophages

  • Ryu, Jae-Ha;Ahn, Han-Na;Lee, Hwa-Jin;Feng, Li;Qun, Wen-He;Han, Yong-Nam;Han, Byung-Hoon
    • Biomolecules & Therapeutics
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    • v.9 no.3
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    • pp.183-187
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    • 2001
  • Nitric oxide (NO) produced in large amounts by the inducible nitric oxide synthase (iNOS) is known to be responsible for the vasodilation and hypotension observed in septic shock and inflammation. The inhibitors of iNOS, thus, may be useful candidate for the treatment of inflammatory diseases accompanied by the overproduction of NO. We prepared alcoholic extracts of Chinese medicinal plants and screened their inhibitory activity against NO production in lipopolysaccharide (LPS)-activated macrophages. Among the 80 kinds of extracts of herbal drugs, 15 extracts showed potent inhibitory activity of NO production above 80% at the concentration o$50\mu\textrm{g}/ml$. These potent extracts showed dose dependent inhibition of NO production of LPS-activated macrophages at the concentration of 50, 30,$10\mu\textrm{g}/ml$. Especially, Rhus chinensis, Senecio scandens and Wikstroemia indica showed most potent inhibition above 50% at the concentration of $10\mu\textrm{g}/ml$. These plants are promising candidates for the study of the activity-guided purification of active compounds and would be useful for the treatment of inflammatory diseases and endotoxemia accompanying the overproduction of NO.

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Effect of Chitosan on Nitric Oxide Content and Inducible Nitric Oxide Synthase Activity in Serum and Expression of Inducible Nitric Oxide Synthase mRNA in Small Intestine of Broiler Chickens

  • Li, H.Y.;Yan, S.M.;Shi, B.L.;Guo, X.Y.
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.7
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    • pp.1048-1053
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    • 2009
  • The present study was conducted to determine the effects of chitosan on nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity in serum, and relative expression of iNOS mRNA in the duodenum, jejunum, and ileum of broiler chickens. A total of 240 one-day-old Arbor Acre mixed-sex broiler chickens were randomly allotted to six dietary treatments with five replicates in each treatment and eight chickens in each replicate. The broiler chickens in the six treatments were fed the basal diet supplemented with 0 (control), 0.05, 0.2, 0.5, 1.0 or 2.0 g/kg chitosan. The trial lasted for 42 days. The results showed that dietary chitosan enhanced NO content and iNOS activity in serum as well as iNOS mRNA expression in the duodenum and ileum of broiler chickens in a quadratic dose-dependent manner (p<0.05), and improved jejunum iNOS mRNA expression in a quadratic dose-dependent manner (p<0.10) with increasing addition of chitosan. Chicks fed a diet containing 0.5-1.0 g/kg chitosan had higher NO content and iNOS activity in serum as well as small-intestinal iNOS mRNA expression compared with birds given the control diet, but positive effects of chitosan tended to be suppressed when addition of chitosan in the diet was increased to 2.0 g/kg. These results implied that there was a threshold level of chitosan inclusion beyond which progressive reductions in serum NO content and small intestinal iNOS expression occured, and the regulation of chitosan on immune functions in chickens is probably associated with activated expression of iNOS and NO secretion.

Nitric Oxide-Mediated Cytotoxicity of Manganese in Basal Ganglia Neuronal Cells (대뇌 기저핵 신경세포에서 Nitric Oxide를 매개로 한 망간의 세포독성)

  • Jung, Yong-Wook;Bae, Jae-Hoon;Song, Dae-Kyu;Park, Won-Kyun;Ko, Bok-Hyun;Kim, Doo-Hie;Shin, Dong-Hoon
    • Journal of Preventive Medicine and Public Health
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    • v.32 no.4
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    • pp.459-466
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    • 1999
  • Objectives:eurotoxicity is mediated by nitric oxide(NO) in the rat primary neuronal cultures and assess the effect of $Mn^{2+}$ on the N-methyl-D aspartate(NMDA) receptors. Methods: We have used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay to examine the effect of cytotoxicity of $MnCl_2$ in neuronal cells , NO production was determined by measuring nirites, a stable oxidation product of NO. The neurons in the rat that contains neuronal nitric oxide synthase(nNOS) were examined by immunofluorescence and confocal microscopy. The effects of $Mn^{2+}$ on the NMDA receptors was assesed by the whole cell voltage clamp technique. Results: We showed that the NO release and NOS expression was increased with 500uM $MnCl_2$ treatment and an NOS inhibitors, $N^G-nitro-L-arginine$, prevented neurotoxicity elicited by manganese. In the electrophysiological study, $Mn^{2+}$ does not block or activate the NMDA receptors and not pass through the NMDA receptors in a neurons of basal ganglia. Conclusions: It is concluded that manganese neurotoxicity in basal ganglia was partially mediated by nitric oxide in the cell culture model.

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Redox-modulation of NMDA receptor activity by nitric oxide congeners

  • Kim, Won-Ki;Stuart A. Lipton
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.125-132
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    • 1995
  • In neurons, nitric oxide(NO) is produced by neuronal nitric oxide synthase following stimulation of N-methyl-D-aspartate(NMDA) receptors and the subsequent influx of Ca$\^$2+/. NO, induced in this manner, reportedly plays critical roles in neuronal plasticity, including neurite outgrowth, synaptic transmission, and long-term potentiation(LTP) (1-7). However, excessive activation of NMDA receptors has also been shown to be associated with various neurological disorders, including focal ischemia, epilepsy, trauma, neuropathic pain and chronic neurodegenerative maladies, such as Parkinson's disease, Hungtington's disease and amyotrophic lateral sclerosis(8). The paradox that nitric oxide(NO) has both neuroprotective and neurodestructive effects may be explained, at least in part, by the finding that NO effects on neurons are dependent on the redox state. This claim may be supported by the recent finding that tissue concentrations of cysteine approach 700 ${\mu}$M in settings of cerebral ischemia (9), levels of thiol that is expected to influence both the redox state of the system and the NO group itself(10).

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Change of the Radiation-induced NO(nitric oxide) in Mice with Treatment by Algin-oligosaccharide (알긴산올리고당 처치 마우스에서 방사선 유도 산화질소의 변화)

  • Jang, Woo-Young;Choi, Seong-Kwan;Dong, Kyung-Rae
    • The Journal of the Korea Contents Association
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    • v.9 no.7
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    • pp.211-217
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    • 2009
  • In order to find out the radioprotective effect of algin-oligosaccharide, this study, with a mouse of which whole body irradiated by 3 Gy radiation once, measured nitric oxide. In nitric oxide test for observing the reaction of cell inflammation, nitric oxide showed decreased in the irradiation control group, while 3 day's treatment group with algin-oligosaccharide before or after irradiation indicated higher than the irradiation control group, especially showed big difference in 3 day's treatment group before irradiation (P<0.001). Consequently, this study inquired into the fact that algin-oligosaccharide with superior antioxidant activity performed radiation protection by increasing promotion of nitric oxide generation and confirmed that natural product with less chemical toxicity was able to be applied as radioprotector.

Suppressive Effects of Chrysanthemum zawadskii var. latilobum Flower Extracts on Nitric Oxide Production and Inducible Nitric Oxide Synthase Expression (구절초 꽃 추출물의 Nitric Oxide 생성과 Inducible Nitric Oxide Synthase 발현 억제 효과)

  • Han, Ji-Young;Kim, Young-Hwa;Sung, Jee-Hye;Um, Yu-Rry;Lee, Yi;Lee, Jun-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.12
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    • pp.1685-1690
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    • 2009
  • In this study, we investigated the effect of C. zawadskii extract on nitric oxide (NO) production, prostaglandin E2 (PGE2) production, protein and mRNA expression of inducible nitric oxide synthase (iNOS) in LPS-induced RAW 264.7 macrophage cells. C. zawadskii extract (5~50 μg/mL) significantly inhibited LPS-induced NO production in a concentration-dependent manner ranging from 23.3% to 100%. Consistent with the inhibitory effect on NO production, C. zawadskii extract inhibited the protein expression and mRNA expression of iNOS. Although flower extracts of C. zawadskii was not effective on the expression of PGE2 and COX-2, flower extracts of C. zawadskii, however, showed a strong anti-inflammatory activity through inhibition of NO production and iNOS expression. The present results suggest that C. zawadskii extract has an inhibitory effect on NO production, and thus can be used as an anti-inflammatory agent.

Korean red ginseng inhibits arginase and contributes to endothelium-dependent vasorelaxation through endothelial nitric oxide synthase coupling

  • Shin, Woosung;Yoon, Jeongyeon;Oh, Goo Taeg;Ryoo, Sungwoo
    • Journal of Ginseng Research
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    • v.37 no.1
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    • pp.64-73
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    • 2013
  • Korean red ginseng water extract (KG-WE) has known beneficial effects on the cardiovascular system via inducting nitric oxide (NO) production in endothelium. Endothelial arginase inhibits the activity of endothelial nitric oxide synthase (eNOS) by substrate depletion, thereby reducing NO bioavailability and contributing to vascular diseases including hypertension, aging, and atherosclerosis. In the present study, we demonstrate that KG-WE inhibits arginase activity and negatively regulates NO production and reactive oxygen species generation in endothelium. This is associated with increased dimerization of eNOS without affecting the protein expression levels of either arginase or eNOS. In a vascular tension assay, when aortas isolated from wild type mice were incubated with KG-WE, NO-dependent enhanced vasorelaxation was observed. Furthermore, KG-WE administered via by drinking water to atherogenic model mice being fed high cholesterol diet improved impaired vascular function. Taken together, these results suggest that KG-WE may exert vasoprotective effects through augmentation of NO signaling by inhibiting arginase. Therefore, KG-WE may be useful in the treatment of vascular diseases derived from endothelial dysfunction, such as atherosclerosis.

Inhibitory Effect of Chan-Su on the Secretion of PGE2 and NO in LPS-stimulated BV2 Microglial Cells

  • Kim, Min-Hee;Lyu, Ji-Hyo;Lyu, Sun-Ae;Hong, Sang-Hoon;Kim, Won-Il;Yoon, Hwa-Jung;Ko, Woo-Shin
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.5
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    • pp.1315-1321
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    • 2008
  • Chan-Su (Venenum bufonis) has long been for a variety of other purposes including treatment of inflammation in the folk medicine recipe. Since nitric oxide (NO) is one of the major inflammatory parameters, we first studied the effects of Chan-Su on NO production in lipopolysaccharide (LPS)-stimulated BV2 microglial cells, Chan-Su inhibited the secretion of NO in BV2 microglial cells, without affecting cell viability, The protein level of inducible nitric oxide synthase (iNOS) was decreased by Chan-Su, And Chan-Su also inhibited production of prostaglandin E2 (PGE2) and expression of cyclooxygenase (COX)-2. Proinflammatory cytokines, such as tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\beta}$ and IL-12, were inhibited by Chan-Su in a dose-dependent manner. And Chan-Su inhibited the degradation of ${IkB-\alpha}$, which was considered to be inhibitor of nuclear factor $(NF)-{\kappa}B$, one of a potential transcription factor for the expression of iNOS, COX-2 and proinflammatory cytokines. These results suggest that Chan-Su could exert its anti-inflammatory actions by suppressing the synthesis of NO through inhibition of $I{\kappa}B-{\alpha}$ degradation.