• 대한수의학회지
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• 제40권4호
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• pp.691-699
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• 2000

We investigated the effects of nitric oxide (NO) donors, S-nitroso-L-cysteine (Cys-NO) and 3-morpholinosydnonimine hydrochloride (SIN-1), on the contractile and electrical activity of the circular muscle of guinea pig gastric antrum by using intracellular microelectrode technique. The gastric antral circular muscle showed spontaneous phasic contraction and slow wave of membrane potential. Cys-NO ($0.001{\sim}10{\mu}M$) and SIN-1 ($0.001{\sim}100{\mu}M$) reduced not only the tonic and phasic contraction but also the amplitude of slow wave in a concentration dependent manner. NO donors were more potent to inhibit phasic contraction than to do slow wave. These inhibitory effects of NO donors were mimicked by the membrane permeable guanosine-3',5'-cyclic monophosphate (cGMP) analogue, 8-bromo-cyclic GMP (8-br-cGMP, $10{\sim}300{\mu}M$). The inhibitory effects of SIN-1 and Cys-NO were antagonized by the guanylate cyclase inhibitor, 1H[ [1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, $10{\mu}M$). These results suggest that the inhibitory effects of NO donors on the mechanical and electrical activity is mainly mediated by cGMP pathway.

• 생명과학회지
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• 제19권2호
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• pp.157-162
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• 2009

Nitric oxide (NO)는 세포 안의 다양한 생리학적, 병리학적 조건에서 확산, 세포 간 messenger와 같은 다양한 기능이 있으며, NO는 암세포나 macrophage 등과 같은 세포에서는 apoptosis를 유도하고, 정상세포나 내피 세포에서는 apoptosis를 억제한다고 보고되어져 있다. NO가 유방암 세포주인 MCF-7 세포에서는 apoptosis를 유도하는지 확인하기 위해 NO donor인 SIN-1을 처리하였다. SIN-1은 48시간 처리 시에도 세포 생존율에 영향을 주지 않았고, 세포주기나 성장 패턴에도 아무런 변화를 주지 않았다. 그러나 p53의 발현은 SIN-1 처리 시간에 따라 증가하였고, bcl-2, MDM2, p21의 발현도 함께 증가하였다. Bax의 발현은 SIN-1 처리 시에 변화가 없었다. MCF-7 세포에서 NO에 의한 apoptosis 억제를 보기 위하여, SIN-1을 선처리한 세포에 $CoCl_2$를 처리하였다. 세포에 $CoCl_2$ 만을 처리한 군에서는 확연한 apoptosis를 나타내었지만, SIN-1을 24 시간 선처리한 세포에서는 apoptosis를 관찰할 수 없었다. Cobalt Chloride에 의해 감소되었던 p53, MDM2, bcl-2 발현 역시 SIN-1을 24시간 선처리한 세포에서 증가하였다. 이런 결과들은 SIN-1에 의해 발현된 MDM2가 p53의 기능을 막으며, 또한 p21과 bcl-2의 발현이 유도되어 apoptosis를 억제함을 제시한다.

• Toxicological Research
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• 제16권1호
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• pp.1-8
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• 2000

Astrocytes generate free radicals including nitric oxide (NO) and reactive oxygen intermediates(ROI) which in turn play roles in the pathogenesis of degenerative diseases and sclerotic changes of the brain. This study was designed to evaluate the mechanism that free radicals contribute to the cytotoxicty of rat neonatal primary astrocytes. Treatment with NO donors alone including soldium nitroprusside(SNP), S-nitrosoglucathinoe (GSNO), and S-nitroso-n-acetylpenicillamine (SNAP) showed a little effect on the death of rat neonatal primary astrocytes, whereas SNP markedly induced the death of RAW 264.7 cells. ROI inculding H2O2 and O2 donor also slightly induced the death of rat primary astrocytes. However, 3-morpholinosydnonimine(SIN-1), a donor of peroxynitrite (ONOO), which is a reactive compound of NO with superoxide, significantly decreased the viability of rat primary astrocytes in a dose-dependent manner. Cells were retarded in outgrowth of viability of cellular processes with cell shrinkage and detachment from culture dishes. Hoechst staining demonstrated that SIN-1-induced cell death might be due to an apoptosis which was characterized by nuclear condensation and fragmentation. SIN-1-induced apoptosis was prevented by the pretreatment with superoxide dismutase (SOD) and catalase in rat primary astorocytes. Furthermore, prevention of the generation of reduced glutathione (GSH) by DL-buthionine-[S, R]-sulfoximine (BSO) aggravated the cytotoxic effects of SNP, benzene triol, and SIN-1 in rat primary astrocytes. Taken together, it is suggested that peroxynitrite may be a major effector of apoptosis and cellular antioxidant system is important for cell survival in rat prima교 astrocytes.

• 한국식품영양과학회지
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• 제44권6호
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• pp.809-815
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• 2015

본 연구에서는 국내산 법제 하수오 메탄올 추출물로부터 생리활성물질을 확인하였고, 추출물의 라디칼 소거능과 LLC-$PK_1$ cell을 이용한 산화적 스트레스 개선 효과를 살펴보았다. HPLC 분석 결과 4종의 생리활성물질인 2,3,5,4'-tetrahydroxystilbene 2-O-${\beta}$-D-glucoside, emodin, chrysophanol 및 rhein을 확인하였다. 특히 주요 화합물인 2,3, 5,4'-tetrahydroxystilbene 2-O-${\beta}$-D-glucoside는 115.02 mg/kg이었다. 법제 하수오 추출물의 DPPH, ABTS, hydroxyl 라디칼 소거능은 농도 의존적으로 증가하였다. 추출물의 $50{\mu}g/mL$ 처리 시 DPPH 라디칼 소거능은 48.4%, ABTS 라디칼 소거능은 57.9% 및 hydroxyl 라디칼 소거능은 81.2%로 나타내었다. 한편 LLC-$PK_1$ cell에서 각각의 NO, $O_2{^-}$, 및 $ONOO^-$ 생성물질인 pyrogallol, sodium nitroprusside(SNP) 및 morpholinosydnonimine(SIN-1) 처리에 의해 유도된 산화적 스트레스 상에서 세포 생존율은 감소하였다. 그러나 법제 하수오 메탄올 추출물은 농도 의존적으로 세포 독성을 저해하였다. 추출물의 $50{\mu}g/mL$ 처리 시 세포 생존율은 각각 82.1%(pyrogallol), 89.1%(SNP) 및 77.6%(SIN-1)였다.

• Preventive Nutrition and Food Science
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• 제18권1호
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• pp.18-22
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• 2013

To investigate radical scavenging effects and protective activities of bitter melon (Momordica charantia) against oxidative stress, in vitro and a cellular system using LLC-$PK_1$ renal epithelial cells were used in this study. The butanol (BuOH) fraction of bitter melon scavenged 63.4% and 87.1% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at concentrations of 250 and $500{\mu}g/mL$, respectively. In addition, the BuOH fraction of bitter melon effectively scavenged hydroxyl radicals (${\cdot}OH$). At all concentrations tested, the scavenging activity of the BuOH fraction was more potent than that of the positive control, ascorbic acid. Furthermore, under the LLC-$PK_1$ cellular model, the cells showed a decline in viability and an increase in lipid peroxidation through oxidative stress induced by pyrogallol, a generator of superoxide anion ($O_2{^-}$). However, the BuOH fraction of bitter melon significantly and dose-dependently inhibited cytotoxicity. In addition, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite ($ONOO^-$) formed by simultaneous releases of nitric oxide and $O_2{^-}$, caused cytotoxicity in the LLC-$PK_1$ cells while the BuOH fraction of bitter melon ameliorated oxidative damage induced by $ONOO^-$. These results indicate that BuOH fraction of bitter melon has protective activities against oxidative damage induced by free radicals.

• Biomolecules & Therapeutics
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• 제17권2호
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• pp.175-180
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• 2009

Taurine is the most abundant free amino acid in the retina and transported into retina via taurine transporter (TauT) at the inner blood-retinal barrier (iBRB). In the present study, we investigated whether the taurine transport at the iBRB is regulated by oxidative stress or disease-like state in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB) used as an in vitro model of iBRB. First, [$^3H$]taurine uptake and efflux by TR-iBRB were regulated in the presence of extracellular $Ca^{2+}$. [$^3H$]Taurine uptake was inhibited and efflux was enhanced under $Ca^{2+}$ free condition in the cells. In addition, oxidative stress inducing agents such as tumor necrosis factor-$\alpha$ (TNF-$\alpha$), lipopolysaccharide (LPS), diethyl maleate (DEM) and glutamate increased [$^3H$]taurine uptake and decreased [$^3H$]taurine efflux in TR-iBRB cells. Whereas, 3-morpholinosydnonimine (SIN-1), which is known to NO donor decreased [$^3H$]taurine uptake. Lastly, TR-iBRB cells exposed to high glucose (25 mM) medium and the [$^3H$]taurine uptake was reduced about 20% at the condition. Also, [$^3H$]taurine uptake was decreased by cytochalasin B, which is known to glucose transport inhibitor. In conclusion, taurine transport in TR-iBRB cells is regulated diversely at extracellular $Ca^{2+}$, oxidative stress and hyperglycemic condition. It suggested that taurine would play a role as a retinal protector in diverse disease states.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.757-762
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• 2004

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (PI3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and PI3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-SHa) a prooxidant chemical. Therefore, the basal PKC activity is req- uisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP ＋ t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a P13-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may playa role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of PI3-kinase.

• 한국식품영양과학회지
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• 제43권5호
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• pp.668-674
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• 2014

채소즙이란 생채소를 마쇄하여 인체가 영양소를 흡수하기 쉬운 상태로 제조된 즙으로 생채소의 영양 섭취 효율을 높일 수 있는 식품이라 할 수 있다. 본 연구에서는 재배방법에 따라 생산된 유기농 및 일반농 케일을 착즙하여 다양한 실험을 통하여 항산화 활성을 비교하였다. DPPH radical, NO, $O_2{^-}$, ${\cdot}OH$ 라디칼 소거능에서 유기농 케일 착즙액은 일반농케일 착즙액보다 더 우수한 효과를 나타내었다. LLC-PK1 세포를 이용하여 산화적 스트레스 개선효과에서 유기농 케일 착즙액은 일반농 케일 착즙액에서보다 NO, $O_2{^-}$와 $ONOO^-$에 의해 유발된 산화적 스트레스에 대한 세포 생존율을 증가시키고, 지질과산화물을 억제시켜 유리라디칼에 대한 보호효과를 유의적으로 나타내었다. 위의 결과로 보아 유기농케일 착즙액은 일반농 케일 착즙액보다 산화적 스트레스에 대한 개선효과가 뛰어난 것으로 사료되며 재배방법의 차이에 따라 그 효과도 차이가 있었다.

• Preventive Nutrition and Food Science
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• 제13권2호
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• pp.90-94
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• 2008

The protective effect of chungkukjang from Sunchang province against oxidative stress was evaluated in the cellular system using LLC-$PK_1$ renal epithelial cells. The LLC-$PK_1$ cells showed decrease in cell viability and elevation in lipid peroxidation by the treatment with the generators of nitric oxide (NO) and superoxide anion ($O_2^-$) produced by sodium nitrouprusside and pyrogallol, respectively. However, the methanol extract of chungkukjang significantly inhibited cellular loss and lipid peroxidation in a dose-dependent manner; in particular K chungkukjang (KC) exerted the strongest protective effect. In addition, the protective effect of chungkukjang from 3-morpholinosydnonimine, as a source of peroxynitrite, with simultaneous generations of NO and $O_2^-$, was also studied. Treatment with chungkukjangs significantly preserved the cell viability and inhibited lipid peroxidation caused by SIN-1 with dose-dependence. The present study suggests that chungkukjang from Sunchang province, especially KC, would have protective potential from oxidative stress induced by free radicals under cellular oxidative damage.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.445-453
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• 2000

The present investigation tested the hypothesis that the activation of protein kinase G (PKG) leads to a phosphorylation of $Ca^{2+}-activated$ potassium channel $(K_{Ca}\;channel)$ and is involved in the activation of $K_{Ca}$ channel activity in cerebral arterial smooth muscle cells of the rabbit. Single-channel currents were recorded in cell-attached and inside-out patch configurations of patch-clamp techniques. Both molsidomine derivative 3-morpholinosydnonimine-N-ethylcarbamide $(SIN-1,\;50\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate $(8-pCPT-cGMP,\;100\;{\mu}M),$ a membrane-permeable analogue of cGMP, increased the $K_{Ca}$ channel activity in the cell-attached patch configuration, and the effect was removed upon washout of the drugs. In inside-out patches, single-channel current amplitude was not changed by SIN-1 and 8-pCPT-cGMP. Application of ATP $(100\;{\mu}M),$ cGMP $(100\;{\mu}M),$ ATP+cGMP $(100\;{\mu}M\;each),$ PKG $(5\;U/{\mu}l),$ ATP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l),$ or cGMP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ did not increase the channel activity. ATP $(100\;{\mu}M)+cGMP\;(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ added directly to the intracellular phase of inside-out patches increased the channel activity with no changes in the conductance. The heat-inactivated PKG had no effect on the channel activity, and the effect of PKG was inhibited by 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer $(Rp-pCPT-cGMP,\;100\;{\mu}M),$ a potent inhibitor of PKG or protein phosphatase 2A (PP2A, 1 U/ml). In the presence of okadaic acid (OA, 5 nM), PP2A had no effect on the channel activity. The $K_{Ca}$ channel activity spontaneously decayed to the control level upon washout of ATP, cGMP and PKG, and this was prevented by OA (5 nM) in the medium. These results suggest that the PKG-mediated phosphorylations of $K_{Ca}$ channels, or some associated proteins in the membrane patch increase the activity of the $K_{Ca}$ channel, and the activation may be associated with the vasodilating action.