• The Korean Journal of Physiology and Pharmacology
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• 제16권3호
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• pp.219-224
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• 2012

Understanding how the b-wave of the electroretinogram (ERG) is generated by full-field light stimulation is still a challenge in visual neuroscience. To understand more about the origin of the b-wave, we studied the contributions of gap junctions to the ERG b-wave. Many types of retinal neurons are connected to similar and different neighboring neurons through gap junctions. The photopic (cone-dominated) ERG, stimulated by a small light beam, was recorded from goldfish (Carassius auratus) using a corneal electrode. Data were obtained before and after intravitreal injection of agents into the eye under a photopic illumination level. Several agents were used to affect gap junctions, such as dopamine D1 and D2 receptor agonists and antagonists, a nitric oxide (NO) donor, a nitric oxide synthase (NOS) inhibitor, the gap junction blocker meclofenamic acid (MFA), and mixtures of these agents. The ERG b-waves, which were enhanced by MFA, sodium nitroprusside (SNP), SKF 38393, and sulpiride, remained following application of a further injection of a mixture with MFA. The ERG b-waves decreased following $N^G$-nitro-L-arginine methyl ester (L-NAME), SCH 23390, and quinpirole administration but were enhanced by further injection of a mixture with MFA. These results indicate that gap junction activity influences b-waves of the ERG related to NO and dopamine actions.

• 대한화장품학회지
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• 제28권1호
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• pp.31-41
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• 2002

The production of matrix matalloproteinases(MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix(ECM) by these enzymes is known as one of the main reasons of photoaging. Recently, Fisher group showed that the MMP expression is mainly regulated by the mitogen-activated protein(MAP) kinas family, such as extracellular signal-regulated kinase(ERK), c-Jun amino-terminal kinase(JNK) and p38, each of which forms a signaling pathway. In this work we first examined the effect of nitric oxide (NO) on the production of MMP-1 and MMP-2 by the human dermal fibroblasts (HDFs). NO is a multifunctional messenger molecule generated from L-arginine and involved in many kinds of signaling pathway. We found that the treatment of HDF with NO donor, sodium nitroprusside (SNP) enhanced the expression of MMPs with or without UV irradiation and the treatment with nitric oxide synthase (NOS) inhibitors resulted in the significant decrease of MMPs production. From these results, we concluded that the production of MMPs by the UV irradiated HDF is regulated through the signaling pathway involving NO and cyclic GMP.

• Journal of Korean Neurosurgical Society
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• 제38권5호
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• pp.366-374
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• 2005

Objective : Nitric oxide[NO] is implicated in a wide range of biological processes in tumors and is produced in glioma. To investigate the role of NO and its interaction with the tumoricidal effects of anticancer drugs, we study the antitumor activities of NO donors, with or without anticancer drugs, in human glioma cell lines. Methods : U87MG and U373MG cells were treated with the NO donors sodium nitroprusside[SNP] and S-nitroso-N-acetylpenicillamine[SNAP], alone or in combination with the anticancer drugs 1,3-bis[2-chloroethyl]-1-nitrosourea[BCNU] and cisplatin. Cell viability, cell proliferation, DNA fragmentation, nitrite level, and the expression of Bcl-2 and Bax were determined. Results : NO was markedly increased after treatment with SNP or SNAP; however, the addition of the anticancer drugs did not significantly affect NO production NO donors or anticancer drugs reduced glioma cell viability and, in combination, acted synergistically to further decrease cell viability in a dose- and time-dependent manner. Cell proliferation was inhibited and apoptosis were enhanced by combined treatment. Bax expression was increased by combined treatment, whereas Bcl-2 expression was reduced. The antitumor cytotoxicity of NO donors and anticancer drugs differed according to cell type. Conclusion : BCNU or cisplatin can inhibit cell viability and proliferation of glioma cells and can induce apoptosis. These effects are further enhanced by the addition of a NO donor which modulates the antitumor cytotoxicity of chemotherapy depending on cell type. Further biological, chemical, and toxicological studies of NO are required to clarify its mechanism of action in glioma.

• The Korean Journal of Physiology and Pharmacology
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• 제1권5호
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• pp.581-589
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• 1997

This study was undertaken to examine the effects of ultraviolet light (UVL) and rebamipide on the cutaneous blood flow and tissue survival on rabbit skin flap. In a random bipedicle flap, Laser Doppler Flowmetry (LDF) was employed to measure the blood flow of flap (BFF). Wound Margin Strength (WMS) measured by force transducer and Light microscophy were used for evaluation of tissue viability. Single exposure to UVL increased the BFF gradually for more than 15 hours, and decreased the vasoconstrictor effect of intravenous phenylephrine. The UVL-induced increase in BFF regressed after 18 hours of irradiation, and this regression was tended to be enhanced by intradermal injection of L-NAME, a nitric oxide synthase (NOS) inhibitor, but the regression was significantly reversed by acetylcholine, an endothelial constitutive NOS (cNOS) activator and L-arginine, an NO precusor. Rebamipide, a novel antiulcer agent known to scavenge the hydroxyl radical, abruptly reversed the spontaneous regression of the UVL- induced increase in BFF by the same manner as L-arginine. In ischemic skin flap, rebamipide increased the BFF abruptly by the same manner as sodium nitroprusside (SNP), an NO doner, while N-acetylcystein (NAC), a free radical scavenger, gradually increase the BFF. The rebamipide-induced increase in BFF was sustained at the level of the SNP-induced increase in BFF during the late period of experiment. Rebamipide increased the WMS of skin flaps and prevented the tissue necrosis in comparison with L-NAME. Based on these results, it is concluded that in rabbit skin, UVL irradiation increases the BFF by NO release, and rebamipide exerts a protective effect on the viability of ischemic skin flaps by either or both the increase in BFF by NO release and free radical scavenger effect.

• 한국약용작물학회지
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• 제16권5호
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• pp.313-319
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• 2008

S. barbata의 열수 추출물 (Sb-HWE)은 대표적인 염증과정인 LPS에 의해 활성화된 대식세포로 부터의 NO생성, LPS 매개에 의한 세포사멸작용, 및 FITC-dextran의 대식세포내 탐식작용을 매우 효과적으로 억제하였다. 그러나 본 추출물은 SNP로 유도된 라디칼 소거능은 매우 미약한 것으로 나타났다. NF-${\kappa}B$-매개에 의한 루시퍼라제 활성, 및 NF-${\kappa}B$ 활성 관련 신호전달 단백질 (Akt 및 $I{\kappa}B{\alpha}$)에 대한 저해작용은 관찰되지 않은 것으로 보아 이들 추출물의 대식세포 면역반응 조절 기전은 기존의 알려진 방법과는 다른 기전에 의해 진행되는 것으로 판단된다.

• Journal of Korean Neurosurgical Society
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• 제30권9호
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• pp.1059-1064
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• 2001

Objective : 6R-Tetrahydrobiopterin(BH4) is a cofactor for the aromatic amino acid hydroxylases which is essential for the biosynthesis of catecholamines and serotonin. It also acts as a cofactor for nitric oxide synthase, and stimulates the release of some neurotransmitters such as dopamine, serotonin, acetylcholine and glutamate. Recently, it has been reported that BH4 could induce cellular proliferation and enhance neuronal survival. This study was performed to investigate the antioxidative effect of BH4 on the various oxidative insults in mouse cerebral cortical cell cultures. Methods : Iron ion(FeCl2), zinc ion(ZnCl2), sodium nitroprusside(SNP) and buthionine sulfoximine(BSO, a glutathione depletor) were used as oxidants. Cell death was assessed by measurement of lactate dehydrogenase efflux to bathing media at the end of exposure. Result : All 4 oxidants induced neuronal cell death associated with cell body swelling, which was markedly inhibited by trolox($100{\mu}M$), a vitamin E analog. BH4($10-100{\mu}M$) markedly inhibited the neuronal cell death induced by all 4 oxidants($20{\mu}M\;Cu^{2+}$, $20{\mu}M\;Zn^{2+}$, $1{\mu}M$ SNP or 1mM BSO). However, BH4 failed to inhibit the neuronal cell death induced by 24hr exposure to $20{\mu}M$ NMDA. Conculsion : These results suggest that BH4 has antioxidative action independently of any actions of enzyme cofactor.

• The Korean Journal of Physiology
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• 제29권1호
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• pp.39-50
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• 1995

This study was designed to clarify the action of cyclic nucleotides, cyclic AMP and cyclic GMP, on phorbol 12,13-dibutyrate (PDBu)-induced contraction in rings isolated from rabbit carotid artery. Arterial rings, 2 mm in width, were myographied isometrically in an isolated organ bath. PDBu produced slowly developing, sustained contraction in rabbit carotid artery, in a dose dependent manner, which was independent of extracellular $Ca^{2+}$ PDBu-induced contraction was relaxed by staurosporine, which suggests that PDBu-induced contraction is mediated by protein kinase C (PKC). $^{45}Ca^{2+}$ uptake by rabbit carotid artery was increased by PDBu during depolarization, but not in control. Isoproterenol and sodium nitroprusside (SNP) relaxed phenylephrine-induced contraction. However, SNP but not isoproterenol relaxed the contraction induced by PDBu. Acetylcholine relaxed PDBu-induced contraction in the presence of the endothelium. 8-bromo-cyclic AMP, a permeable analogue of cyclic AMP, suppressed phenylephrine-induced contraction but not PDBu-induced contraction. 8-bromo cyclic GMP relaxed both of them with dose dependency. A large dose of forskolin relaxed PDBu-induced contraction. PDBu increased cyclic AMP without considerable change in the level of cyclic GMP. Based on these findings, PDBu-induced contraction of rabbit carotid artery was relaxed by cyclic GMP more effectively than cyclic AMP, and the action of cyclic AMP could be mediated by cyclic GMP dependent protein kinase. Therefore it is suggested that the antagonistic action between protein kinase C and cyclic GMP-dependent protein kinase plays a major role in the regulation of vascular tone.

• 대한약침학회지
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• 제22권3호
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• pp.160-165
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• 2019

Objectives: The aim of this study was to evaluate the effect of Ribes khorasanicum (R. khorasanicum); a plant growing in north Khorasan of Iran; on cardiovascular and stress oxidative in acute hypertension induced by N-nitro-l-arginine methyl ester (L-NAME), anitric oxide synthase inhibitor. Methods: Rats were divided into Control, L-NAME (10 mg/kg), Sodium Nitroprusside (SNP) (50 mg/kg) + L-NAME and three treated groups with R. khorasanicum (4, 12 and 24 mg/kg) groups + L-NAME. L-NAME and SNP were injected intravenously and extract intraperitoneal. In R. khorasanicum groups, L-NAME was injected 30 min after injection of the extract. Systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were recorded continuously using power lab software. At the end of study oxidative stress parameters including of total thiol content (SH), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in heart and aorta of all groups were also measured. Results: In groups 4 and 24 mg/kg extract +L-NAME, there was a non-significant decrease in SBP and MAP compared to L-NAME group but dose 12 mg/kg significantly attenuate the effect of L-NAME(P < 0.05). In L-NAME group the heart and aorta tissues antioxidant enzymes levels decreased, while in treated rats these enzymes significantly increased. Conclusion: The extract of R. khorasanicum in dose 12 mg/kg show anti-hypertensive effect that is mediated by an effect on NO system or antioxidant parameters.

• 한국식품영양과학회지
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• 제37권10호
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• pp.1238-1243
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• 2008

잔대 뿌리는 우리나라에서 예로부터 민간약으로 이용되어 오고 있다. 본 연구에서는 인간 간세포인 HepG2에 잔대 뿌리의 에틸아세테이트 추출물을 처리했을 때 sodium nitroprusside(SNP)에 의해 유도된 세포 독성 및 항산화 유전자 발현에 미치는 영향력을 알아보았다. 먼저, 잔대 에틸아세테이트 추출물이 NO에 의해 유도된 세포 사멸을 저해할 수 있는지를 알아보기 위하여 HepG2 세포에 잔대 에틸아세테이트 추출물(각각 50과 100 $\mu$g/mL)을 24시간 먼저 처리한 후 세포내에서 NO을 생성시킬 수 있는 0.5 mM SNP를 처리하였다. NO에 의한 세포독성이 에틸아세테이트 추출물에 의해 저해되었다는 것을 mitochondrial dehydrogenase 활성을 알아보는 MTT assay를 실시하여 알아보았다. 더하여 우리는 잔대 에틸아세테이트 추출물이 세포내 항산화 방어 시스템인 Cu,Zn superoxide dismutase(SOD 1), Mn SOD(SOD 2), glutathione peroxidase(GPx), catalase와 glutathione metabolism과 관련되어져 있는 glutathione reductase(GR), $\gamma$-glutamyl-cystein synthetase(GCS), glutathione-S-transferase(GST), $\gamma$-glutamyltranspeptidase($\gamma$-GT), glucose-6-phosphate dehydrogenase(G6PD)의 mRNA 발현에 미치는 영향을 RT-PCR로 알아보았다. CAT, GCS 그리고 G6PD mRNA 수준이 잔대 에틸아세테이트 추출물 처리 후 증가하였으나, SOD 1, SOD 2, GPx, GST 그리고 $\gamma$-GT mRNA 수준은 변화지 않았다. 따라서 잔대 에틸아세테이트 추출물이 간접적 항산화 효과가 있고, 이들 효과는 아마 CAT, GCS, GR 그리고 G6PD 유전자 발현 증가에 의한 것이라고 추정되었다.

• 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.