• Title/Summary/Keyword: inhibitory mechanism

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Ketamine-Induced Blood Pressure Lowering in the Rat (흰쥐에서 Ketamine에 의한 혈압하강)

  • Yu Xian-Feng;Kim Shang-Jin;Lee Mun-Young;Kang Hyung-Sub;Kim Jin-Shang
    • Journal of Veterinary Clinics
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    • v.22 no.3
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    • pp.220-227
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    • 2005
  • Although ketamine has been used in the field of anesthetic medicine for its safety and favourable respiratory effects, the cardiovascular effects of ketamine is still controversial. To clarify the action and mechanism of ketamine upon cardiovascular system, arterial blood pressure, tension of aortic ring, left ventricular developed pressure and heart rate were measured in rats, Ketamine produced two types of effects on arterial blood pressure in anesthetized rats; monophasic effect (blood pressure lowering) and biphasic effect (initial transient blood pressure increasing following sustained lowering), The ketamine-induced lowering of aterial blood pressure showed a concentration-dependent manner, inhibited by the pretreament of $MgCl_2$ and potentiated by the pretreatment of $CaCl_2$. The ketamine-induced lowering of aterial blood pressure was suppressed by the pretreatment of nifedipine, verapamil or lidocaine. In phenylephrine-precontracted endothelium intact (+E) aortic rings, ketamine sometimes caused a small enhancement of contraction ($112.5{\pm}3.6{\%}$). However, in many experiments, ketamine produced a concentration-dependent relaxation in +E aortic rings precontracted with either phenylephrine or KCl. Ketamine-induced relaxation was significantly greater in KCl-precontracted strips than phenylephrine-precontracted strips. In phenylephrine-precontracted +E aortic rings, the ketamine-induced vasorelaxation was not suppressed by endothelium removal or by the pretreatment of a nitric oxide synthase inhibitors, L-$N^G$-nitro-arginine and a guanylate cyclase inhibitors, methylene blue, suggesting that the ketamine-induced vasorelaxation is not dependent on the endothelial function. In addition, ketamine elicited an increase in left ventricular developed pressure in perfused hearts accompanied by decrease in heart rate. These results suggest that ketamine could evoke a hypotension due to vasorelaxation and decrease in heart rate in rats. The inhibitory effect of cardiovascular system might be associated with modulation of $Ca^{2+}$ homeostasis.

Selective Mechanism of Cyhalofop-butyl ester between Rice and Echinochloa crus-galli - 2. Anatomical influence of Cyhalofop-butyl ester on rice and Echinochla crus-galli (제초제(除草劑) Cyhalofop-butyl ester의 벼와 피간(間) 선택성기작(選擇性機作) - 2. 제초제(除草劑) cyhalofop-butyl ester의 벼와 피간(間)에 미친 해부학적(解剖學的) 영향(影響))

  • Park, J.E.;Ryu, G.H.;Lee, I.Y.;Lee, H.K.;Shin, H.S.;Lee, J.O.;Kim, K.U.
    • Korean Journal of Weed Science
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    • v.14 no.3
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    • pp.223-227
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    • 1994
  • Basis for differential response of rice and E. crus-galli to cyhalofop-butyl ester (R-butyl 2-(4-(4-cyano-2-fluoro-phenoxy)phenoxy)propionate) was anatomically compared. Cell division in the growing point of E. crus-galli was severely inhibited by the herbicide, leading to malformation and irregular arrangement of cells. The inhibitory symptom of rice by cyhalofop-butyl ester appeared to be very similiar to that of E. crus-galli although its injury was negligible in rice when applied at the rate of 180ppm.

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Molecular Cloning of the DNA Gyrase Genes from Methylovorus Sp. Strain SS1 and the Mechanism of Intrinsic Quinolone Resistance in Methylotrophic Bacteria

  • Kim, Kwang-Seo;Kim, Jeong Hoon;Kim, Do Yeob;Kim, Hyun Jong;Park, Sang Tae;Kim, Young Min
    • Molecules and Cells
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    • v.20 no.3
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    • pp.392-400
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    • 2005
  • The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The $Ser^{83}$ to Thr substitution in Methylovorus sp. strain SS1, and the $Ser^{83}$ to Leu and $Asp^{87}$ to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.

Anticancer Activity of the Safflower Seeds (Carthamus tinctorius L.) through Inducing Cyclin D1 Proteasomal Degradation in Human Colorectal Cancer Cells

  • Park, Gwang Hun;Hong, Se Chul;Jeong, Jin Boo
    • Korean Journal of Plant Resources
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    • v.29 no.3
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    • pp.297-304
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    • 2016
  • The seed of safflower (Carthamus tinctorius L) has been reported to suppress human cancer cell proliferation. However, the mechanisms by which safflower seed inhibits cancer cell proliferation have remained nuclear. In this study, the inhibitory effect of the safflower seed (SS) on the proliferation of human colorectal cancer cells and the potential mechanism of action were examined. SS inhibited markedly the proliferation of human colorectal cancer cells (HCT116, SW480, LoVo and HT-29). In addition, SS suppressed the proliferation of human breast cancer cells (MDA-MB-231 and MCF-7). SS treatment decreased cyclin D1 protein level in human colorectal cancer cells and breast cancer cells. But, SS-mediated downregulated mRNA level of cyclin D1 was not observed. Inhibition of proteasomal degradation by MG132 attenuated cyclin D1 downregulation by SS and the half-life of cyclin D1 was decreased in SS-treated cells. In addition, SS increased cyclin D1 phosphorylation at threonine-286 and a point mutation of threonine-286 to alanine attenuated SS-mediated cyclin D1 degradation. Inhibition of ERK1/2 by PD98059 suppressed cyclin D1 phosphorylation and downregulation of cyclin D1 by SS. In conclusion, SS has anti-proliferative activity by inducing cyclin D1 proteasomal degradation through ERK1/2-dependent threonine-286 phosphorylation of cyclin D1. These findings suggest that possibly its extract could be used for treating colorectal cancer.

Artemisia fukudo essential oil attenuates LPS-induced inflammation by suppressing NF-${\kappa}B$ and MAPK activation in RAW 264.7 cells

  • Yoon, Weon-Jong
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2010.10a
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    • pp.13-13
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    • 2010
  • In the present study, the chemical constituents of Artemisia fukudo essential oil (AFE) were investigated using GC-MS. The major constituents were ${\alpha}$-thujone (40.28%), ${\beta}$-thujone (12.69%), camphor (6.95%) and caryophyllene (6.01%). We also examined the effects of AFE on the production of nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-IL-$1{\beta}$ (IL-$1{\beta}$), and IL-6 in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Western blotting and RT-PCR analyses indicated that AFE has potent dose-dependent inhibitory effects on pro-inflammatory cytokines and mediators. We investigated the mechanism by which AFE inhibits NO and $PGE_2$ by examining the level of nuclear factor-${\kappa}B$ (NF-${\kappa}B$: p50 and p65) activation within the mitogen-activated protein kinase (MAPK: ERK, JNK and p38) pathway, which is an inflammation induced signal pathway in RAW 264.7 cells. AFE inhibited LPS-induced ERK, JNK and p38 phosphorylation. Furthermore, AFE inhibited the LPS-induced phosphorylation and degradation of $I{\kappa}B-{\alpha}$, which is required for the nuclear translocations of the p50 and p65 NF-${\kappa}B$ subunits in RAW 264.7 cells. Our results suggest that AFE might exert an anti-inflammatory effect by inhibiting the expression of pro-inflammatory cytokines. Such an effect is mediated by a blocking of NF-${\kappa}B$ activation which consequently inhibits the generation of inflammatory mediators in RAW 264.7 cells. AFE may be useful for treating inflammatory diseases.

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Antioxidant and Anti-inflammatory Activities of Tetragonia tetragonoides Water Extract (번행초 추출물의 항산화 및 항염증 효과)

  • Kong, Ji Hyun;Lee, Ki Yeon;Rho, Dae Hyun;Lee, Jang-Cheon;An, Won Gun;Lee, Boo-Kyun
    • Herbal Formula Science
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    • v.28 no.2
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    • pp.137-145
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    • 2020
  • Objectives : Tetragonia tetragonioides is one of the traditional herbal medicines that can be used to protect the stomach and treat cancer. However, its mechanism of overcoming gastrointestinal disorders is unclear. In this study, we investigated antioxidant and anti-inflammatory effects of Tetragonia tetragonioides Water Extract (TTWE) on RAW264.7 cells. Methods : The cell viability by TTWE was measured by using MTT assay. The free radical scavenging ability and cytokine production were analyzed by using ELISA Kit. SPSS version 25 was used for statistical analysis. Results : According to the results of this study, the cell viability measurement of TTWE significantly affected the cell viability. The radical scavenging ability of TTWE showed the highest effect compared to the positive control group when the concentration was 3.1-12.5 ㎍/ml, and significantly inhibited NO production induced by LPS. In addition, the inhibitory effect of TTWE on the production of IL-6 and TNF-α induced by LPS was significant at both TTWE concentrations of 12.5 ㎍/ml [p <0.01 (IL-6), p <0.05 (TNF-α)]. Conclusion : In conclusion, it is suggested that the antioxidant function of Tetragonia tetragonioides Water Extract could be used to prevent and treat inflammatory diseases.

Inhibition of Nitric Oxide Synthesis by Methanol and Butanol Extracts of Euonymus Alatus (Thunb.) Sieb in Murine Macrophages

  • Lee Hyo-Hyun;Park Young-Soo;Kim Ra-Young;Kim Dong-Il;Lee Tae-Kyun
    • The Journal of Korean Medicine
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    • v.26 no.1 s.61
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    • pp.26-36
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    • 2005
  • Objective : Many traditional herbal remedies exhibit several beneficial effects including anti-inflammation. Euonymus alatus (Thunb.) Sieb (EA), known as Gui jun woo in Korea, has long been used in folk medicine to regulate Qi (bodily energy) and blood circulation, relieve pain, eliminate stagnant blood, and treat dysmenorrhea in oriental countries. The exact mechanism of the anti-inflammatory action of Euonymus alatus (Thunb.) Sieb (EA), however, has not been determined. Methods: Since there is increasing evidence that nitric oxide (NO) plays a crucial role in the pathogenesis of inflammatory diseases, this study was undertaken to address whether the methanol (MeOH) extract and its fractions of the bark of EA could modulate the expression of inducible NO synthase (iNOS) in thioglycollate-elicited murine peritoneal macrophages and murine macrophage cell line, RA W264.7 cells. Results: Stimulation of the peritoneal macrophages and RAW264.7 cells with $interferon-\gamma\;(IFN-\gamma)$ and lipopolysaccharide (LPS) resulted in increased production of NO in the medium. However, the butanol (BuOH) fraction of the MeOH extract of EA barks showed marked inhibition of NO synthesis in a dose-dependent manner. The inhibition of NO synthesis was reflected in the decreased amount of iNOS protein, as determined by Western blotting. The BuOH fraction did not affect the viability of RA W264.7 cells, as assessed by methylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide (MTT) assay; rather, it reduced endogenous NO-induced apoptotic cell death via inhibition of NO synthesis in RAW264.7 cells. On the other hand, the MeOH and BuOH fraction showed no inhibitory effect on the synthesis of NO by RAW264.7 cells, when iNOS was already expressed by the stimulation with $IFN-\gamma$ and LPS. Conclusion: Collectively, these results demonstrate that the MeOH and BuOH fraction inhibits NO synthesis by inhibition of the induction of iNOS in murine macrophages.

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The Effects of Injinchunggantang-derivative on Cell Viability, Cell Cycle Progression and Apoptosis of Hepatocytes (인진청간탕가미방(茵陳淸肝湯加味方)이 간세포활성(肝細胞活性), 세포주기(細胞週期) 및 APOPTOSIS에 미치는 영향(影響))

  • Hong, Sang-Hoon;Lee, Jang-Hoon;Woo, Hong-Jung
    • The Journal of Korean Medicine
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    • v.19 no.2
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    • pp.337-372
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    • 1998
  • To evaluate the effects of Injinchunggantang-derivative on cell viability, cell cycle progression, and apoptosis, MTT assay, cell cycle analysis, Cpp32 protease assay, DNA fragnemtation assay, quantitative RT-PCR, and Western blotting were performed. The results were as followes. In MTT assay, etoposide+Injinchunggantang-derivative-treated cells as well as Injinchunggantang-derivative-treated cells showed higher viability than etoposide-treated cells with no time-concentration-dependence, which implied that Injinchunggantang-derivative has hepato-protective effect Cell cycle analysis showed that Injinchunggantang-derivative has no significant effect on the cell cycle. Cpp32 protease assav and DNA fragmentation assay Injinchunggantang-derivative carry inhibitory effects on apoptosis induction. It was suggested that Injinchunggantang-delivative might regulate the cell cycle, in particular $G_1$ checkpoint by blocking p53 and Watl pathway. Injinchunggantang-derivative inhibited the mRNA expressions of Cpp32, Fas, and Bcl-2, which could result in inhibition of apoptosis. These results imply that Injinchunggantang-derivative increases hepatocyte viability, and protects hepatocyte from damage by regulating the expression of genes associated with cell cycle and apoptosis, which explains the mechanism of the clinical effect of Injinchunggantang-derivative on liver diseases.

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Effect of Ginseng on $Na^+$, $K^{+}-ATPase$ Activities of Potassium Deficient Rat Intestinal Mucosa (인삼이 칼륨결핍랫트 장점막의 $Na^+$,$K^{+}-ATPase$ 활성에 미치는 영향)

  • Lee, Myong-Hee;Kim, Nak-Doo
    • YAKHAK HOEJI
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    • v.32 no.1
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    • pp.62-69
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    • 1988
  • We have studied the effect of fasting on $Na^+$, $K^{+}-ATPase$ activities in the rat intestinal mucosa. Rats were fasted for $18{\sim}48hr$. Intestinal microsomal fraction was prepared by the method of Robinson and ATPase activities were determined by the modified method of Fiske and Subbarow. $Na^+$, $K^{+}-ATPase$ activity was not changed after fasting for 18 and 24 hr but significantly decreased after fasting for 48 hr. Fasting over 18 to 48 hr period had no effect on the $Mg^{++}-ATPase$. Thus, it may be concluded that 48 hr fasting has inhibitory effect on rat intestinal absorptive capabilities. In order to study the effect of Ginseng on the $Na^+$, $K^{+}-ATPase$ activities of the small intestine in chronic $K^{+}-depleted$ rats, rats were fed $K^{+}-depleted$ diets for 3 weeks and Ginseng ethanol extracts were administered orally for 3 weeks concomitantly. ATPase activity was measured by the same method as fasting group. $Na^+$, $K^{+}-ATPase$ activity in the $K^{+}-depleted$ diet group was increased and Ginseng ethanol extracts inhibited the increase of enzyme activity induced by $K^{+}-depleted$ diet. Thus, it may be suggested that increase in the intestinal $Na^+$, $K^{+}-ATPase$ activity of chronic $K^{+}-depleted$ group may be due to the compensatory mechanism and administration of Ginseng with $K^{+}-depleted$ diet may be associated with inhibition of increase in the enzyme activity of the $K^{+}-depleted$ group due to the prevention of the $K^+$ loss in the $K^{+}-depletion$.

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The Inhibitory Effects of Bee Venom and Melittin on the Proliferation of Vascular Smooth Muscle Cells

  • Ha, Seong-Jong;Song, Ho-Sueb
    • Journal of Acupuncture Research
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    • v.23 no.2
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    • pp.139-157
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    • 2006
  • In the present study, I have investigated the bee venom (BV) and melittin (a major component of BV) -mediated anti-proliferative effects, and defined its mechanisms of action in cultured rat aortic vascular smooth muscle cells (VSMCs). BV and melittin $(0.4{\sim}0.8\;{\mu}g/ml)$ effectively inhibited 50 ng/ml platelet derived growth factor BB (PDGF-BB)-induced VSMCs proliferations. The regulation of apoptosis has attracted much attention as a possible means of eliminating excessively proliferating VSMCs. In the present study, the treatment of BV and melittin strongly induced apoptosis of VSMCs. I examined the effects on $NF-{\kappa}B$ activation to investigate a possible mechanism for anti-proliferative effects of BV and melittin, the PDGF-BB-induced $I{\kappa}B{\alpha}$ phosphorylation and its degradation were potently inhibited by melittin, and DNA binding activity and nuclear translocation of $NF-{\kappa}B$ p50 subunit in response to the action of PDGF-BB were potently attenuated by melittin. In further investigations, melittin markedly inhibited the PDGF-BB-induced phosphorylation of Akt but not ERK1/2, upstream signals of $NF-{\kappa}B$. Treatment of melittin also potently induced pro-apoptotic protein p53, Bax, and caspase-3 expression, but decreased anti-apoptotic protein Bcl-2 expression. These results suggest that the anti-proliferative effects of BV and melittin in VSMCs through induction of apoptosis via suppressions of $NF-{\kappa}B$ and Akt activation, and enhancement of apoptotic signal pathway. Based on these results, BV acupuncture can be a candidate as a therapeutic method for restenosis and atherosclerosis.

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