• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.507-515
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• 2005

Melatonin, the principal hormone of the vertebral pineal gland, participates in the regulation of cardiovascular system in vitro and in vivo. However, the effects of melatonin on vascular tissues are still vague. The aim of this study was to assess the relationship between phospholipase C (PLC) and nitric oxide synthase (NOS)/cyclic guanosine 3',5'-monophosphate (cGMP) signaling cascade in the relaxatory action of melatonin in isolated rat aorta. Melatonin induced a concentration-dependent relaxation in phenylephrine (PE)- and KCl-precontracted endothelium intact (+E) aortic rings. In KCl-precontracted +E aortic rings, the melatonin-induced vasorelaxation was not inhibited by endothelium removal or by pretreatment with NOS inhibitors, L-$N^G$-nitor-arginine (L-NNA) and L-$N^G$-nitor-arginine methyl ester (L-NAME), guanylate cyclase (GC) inhibitors, methylene blue (MB) and 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ). In PE-precontracted +E aortic rings, the melatonin-induced vasorelaxation was inhibited by endothelium removal or by pretreatment with L-NNA, L-NAME, MB, ODQ and 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC). Moreover, in without endothelium (-E) aortic rings and in the presence of L-NNA, L-NAME, MB and ODQ in +E aortic rings, the melatonin-induced residual relaxations and residual contractile responses to PE were not affected by NCDC, a PLC inhibitor. It is concluded that melatonin can evoke vasorelaxation due to inhibition of PLC pathway through the protein kinase G activation of endothelial NOS/cGMP signaling cascade.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.4
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• pp.215-221
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• 2005

We investigated the effects of testosterone and dihydrotestosterone on inflammatory response of iNOS and COX-2 expression in rat vascular smooth muscle cells. Rat vascular smooth muscle cells (VSMC) stimulated with bacterial lipopolysaccharide $(LPS;\;10{\mu}g/ml)$ for 24 hours were incubated with increasing amounts of testosterone and dihydrotestosterone (1 and 100 nM). LPS was found to induce inflammatory response of iNOS and COX-2 mRNA and protein in VSMC. These processes were affected by male sex steroid hormones. For 3 hours, however, pretreatment of the cells with 100 nM each of testosterone and dihydrotestosterone suppressed LPS induced iNOS and COX-2 protein expression. RT-PCR analysis revealed that testosterone and dihydrotestosterone did not inhibit mRNA expression of iNOS and COX-2 stimulated by 24 hours of LPS incubation. Proliferation rate was slower in VSMC treated with testosterone and dihydrotestosterone. Testosterone enhanced androgen receptor expression, and LPS significantly reduced androgen receptor protein expression in VSMC. These results indicate that the expression of both iNOS and COX-2 proteins was suppressed by testosterone and dihydrotestosterone in LPS stimulated VSMC and leading to reduction of vascular inflammation.

• Korean Journal of Acupuncture
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• v.21 no.4
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• pp.83-99
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• 2004

Objectives : Daeganghwal-Tang(DGHT) is one of the prescriptions used for the treatment of rheumatoid arthritis(RA) in oriental medicine. The present study aimed to examine the analgesic effect of DGHT on a rat model of CFA-induced arthritis, and the relations between DGHT-induced analgesia and endogenous nitric oxide(NO) and inducible NO synthase(iNOS)/neuronal NOS. Methods : CFA-induced arthritis model used to test the effect of DGHT was chronic pain model. After the induction of arthritis, rats subsequently showed a reduced stepping force of the affected limb for at least the next 18 days. the reduced stepping force of the limb was presumably due to a painful knee. DGHT dissolved in water was orally administrated. After the treatment, behavioral tests measuring stepping force were periodically conducted during the next 4 hours. Results : DGHT produced significant improvement of stepping force of the hindlimb affected by the arthritis lasting at least 2 hours. DGHT produced the improvement of stepping force of the affected hindlimb in a dose-dependent manner. Both NO production and nNOS/iNOS protein expression which is increased by arthritis were suppressed by DGHT administration. Conclusions : The data suggest 1) that DGHT produces a potent analgesic effect on the chronic knee arthritis pain model in the rat and 2) that DGHT-induced analgesia modulate endogenous NO through the suppression of nNOS/iNOS protein expression.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.315-320
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• 2013

Here, we show that radicicol, a fungal antibiotic, resulted in marked inhibition of inducible nitric oxide synthase (iNOS) transcription by the pancreatic beta cell line MIN6N8a in response to cytokine mixture (CM: TNF-${\alpha}$, IFN-${\gamma}$, and IL-$1{\beta}$). Treatment of MIN6N8a cells with radicicol inhibited CM-stimulated activation of NF-${\kappa}B$/Rel, which plays a critical role in iNOS transcription, in a dose-related manner. Nitrite production in the presence of PD98059, a specific inhibitor of the extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) pathway, was dramatically diminished, suggesting that the ERK1/2 pathway is involved in CM-induced iNOS expression. In contrast, SB203580, a specific inhibitor of p38, had no effect on nitrite generation. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking ERK1/2 signaling. Due to the critical role that NO release plays in mediating destruction of pancreatic beta cells, the inhibitory effects of radicicol on iNOS expression suggest that radicicol may represent a useful anti-diabetic activity.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.6
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• pp.253-257
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• 2007

Among the arthritis symptoms, chronic pain is the most serious, and it can profoundly affect the quality of human life. Unfortunately, the mechanism of development in arthritis and arthritic pain has not yet been precisely elucidated. Accumulating evidence indicates that nitric oxide (NO) plays a pivotal role in nociceptive processing in the spinal cord. However, the modulation mechanism of NO in the peripheral site of arthritis and arthritic pain has not been clarified. Therefore, I determined in the present study which nitric oxide synthase (NOS) was involved in the induction of arthritis and arthritic pain. Monoarthritis was induced by intra-articular injection of carrageenan (2%, $50{\mu}l$) into rats, and resulted in the reduction of weight load on the injected leg, increase of knee joint diameter and inflammatory response. Pre-treatment of rats with L-N6-(1-iminoethyl)-lysine (L-NIL, $500{\mu}g$, in $50{\mu}l$), an inhibitor of inducible NOS (iNOS), partially prevented the induction of pain-related behavior and partially reduced inflammatory response in the synovial membrane in the knee joint. These results suggest that iNOS in the knee joint may play an important role in the induction of pain-related behavior and inflammation, and that NO produced by iNOS may be associated with nociceptive signaling in the peripheral site.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.411-417
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• 2005

Aqueous extracts were prepared from 21 medicinal herbs including Herba Pogostemi (Agastache rugosa) to examine their modulatory effects on NO production in mouse macrophage cell line RAW264.7 cells. While almost all medicinal herb extracts failed to show marked scavenging activities to NO produced by LPS stimulation, only Herba Pogostemi showed a rather strong induction of NO production in RAW264.7 cells without stimulation with LPS. When we treated the cell with $200{\mu}M\;of\;N^G-monomethyl-L-arginine\;(N^GMMA)$, a NOS2 inhibitor, a significant reduction in NO production could be observed. Moreover, a treatment of $100{\mu}M$ pyrrolidine dithiocarbamate (PDTC) led to about a 79% reduction of NO production. These results demonstrated that the aqueous extract of Herba Pogostemi might provide a second signal for the expression of NOS2 in RAW264.7 cells, and suggested that Herba Pogostemi induces NO production through L-argininedependent pathway.

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.105-111
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• 1999

Nitric oxide (NO), a cellular messenger synthesized from L-arginine by NO synthase (NOS, EC.1.14.13.39), is considered to be a regulator of gastric secretion. In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat gastric chief cells. Treatment of chief cells with carba-chol resulted in an increase in the arginine conversion to citrulline, the amount of $NO_{x}$, the release of pepsine-gen, and the level of cGMP Especially, carbachol-stimulated increase of arginine to citrulline transformation, the amount of $NO_{x}$, cGMP level and the release of pepsinogen were partially reduced by the natural NOS inhibitor, $N^{G}$-monomethyl-L-arginine (MMA) and $N^{G}$, $N^{G}$-dimethyl-L-arginine (DMA). Furthermore, MMA- and DMA-induced decrease of pepsinogen secretion showed dose-dependent patters. Activation of NOS is one of the early events in receptor-mediated cascade of reactions in gastric chief cells and NO, not completely, but partially mediates gastric secretion. Agonist-stimulated pepsinogen secretion in chief cells has been considered to be mediated in adenosine 3',5'-cyclic monophosphate pathway and/or guanosine 3', 5'-cyclic monophosphate (cGMP) pathway. Taken together, the above results suggest that partial decrease of exocrine secretion following treatment of NOS inhibitor may result from the inactivation of NOS and subsequent guano- late cyclase, and NO/cGMP pathway may play a pivotal role in exocrine secretion.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.145-151
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• 2006

We investigated the effects of Ginsenoside $R_e$ on human sperm motility in fertile and asthenozoospermic infertile individuals in vitro and the mechanism by which the Ginsenosides play their roles. The semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Spermatozoa were separated by Percoll and incubated with 0, 1, 10 or $100\;{\mu}M$ of Ginsenoside $R_e$. Total sperm motility and progressive motility were measured by computer-aided sperm analyzer (CASA). Nitric oxide synthase (NOS) activity was determined by the $^{3}H$-arginine to $^{3}H$-citrulline conversion assay, and the NOS protein was examined by the Western blot analysis. The production of sperm nitric oxide (NO) was detected using the Griess reaction. The results showed that Ginsenoside $R_e$ significantly enhanced both fertile and infertile sperm motility, NOS activity and NO production in a concentration-dependent manner. Sodium nitroprusside (SNP, 100 nM), a NO donor, mimicked the effects of Ginsenoside $R_e$. And pretreatment with a NOS inhibitor $N^{w}$-Nitro-L-arginine methyl ester (L-NAME, $100\;{\mu}M$) or a NO scavenger N-Acetyl-L-cysteine (LNAC, 1 mM) completely blocked the effects of Ginsenoside $R_e$. Data suggested that Ginsenoside $R_e$ is beneficial to sperm motility, and that induction of NOS to increase NO production may be involved in this benefit.

• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.143-147
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• 2006

In the mouse leukemic monocyte cell line RAW 264.7, the vacuolar-type $(H^+)$-ATPase (V-ATPase) inhibitor bafilomycin $A_1$ at 10 and 100 nM decreased cell growth and survival as determined by 3-(4,5-dimethyl(thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in a concentration-dependent manner. At such concentrations, bafilomycin $A_1$ induced nitric oxide (NO) production through the expression of inducible nitric oxide synthase (iNOS). The bafilomycin $A_1$-induced NO production was inhibited by the NOS inhibitor $N^G$-monomethyl-L-arginine acetate (L-NMMA). Our findings suggest that the V-ATPase inhibitor bafilomycin $A_1$ induces NO production through the expression of iNOS protein.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.305-310
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• 2007

This study was designed to investigate the effects of KH-305 on erectile dysfunction in young rats, via nitric oxide (NO)-cGMP pathways. After oral administration of the KH-305 mixture (50, 100, 200, 300 mg/kg) to young rats for 10 days, NOS and SOD protein expressions in penile tissue and testosterone in plasma were measured. cGMP degradation was also investigated using bovine vascular smooth muscle cells pretreated with an NO donor, S-nitroso-N-Acetylpenicillamine (SNAP). The penile expression levels of nNOS and eNOS-dependent NOS activities as well as SOD preventing oxidative stress by overproduction of NO were increased significantly. Also, the concentration of testosterone in the plasma was increased. In vitro, cGMP concen-trations were decreased dose dependently in the KH-305. These results suggest that KH-305 may be useful in erectile dysfunction.