• Title/Summary/Keyword: A3 agonist

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The Analgesic Effect and the Mechanism of Electroacupuncture on Thermal Hyperalgesia in the Rat Model of Collagenase-induced Arthritis: Mediation by Adrenergic Receptors (Collagenase-induced Arthritis Rat Model에서 Thermal Hyperalgesia에 대한 전침(電鍼)의 진통효과(鎭痛效果) 및 기전연구: Adrenergic Mechanism에 대(對)한 연구(硏究))

  • Seo, Byung-Kwan;Park, Dong-Suk;Baek, Yong-Hyeon
    • Journal of Acupuncture Research
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    • v.28 no.2
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    • pp.57-67
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    • 2011
  • 목적 : Collagenase-induced osteoarthritis(OA) 동물 모델에서 전침의 adrenergic mechanism을 연구하고자 한다. 방법 : Collagenase-induced arthritis(CIA)를 유발하기 위하여 5주령의 male Sprague-Dawley rat의 뒷다리 좌측 무릎 관절에 0.05ml의 4mg/ml collagenase solution을 intra-articular 주입하고, 다시 4일 후에 같은 부위에 같은 농도의 collagenase solution을 intra-articular boosting injection 시행한 뒤, gross, histopathological features 및 biomarker activity 변화를 관찰하였다. 예비실험을 통하여 CIA rat model에서 진통효과를 발휘하는 것으로 확인한, 족삼리(足三里) ($ST_{36}$)에 대한 저빈도 train pulse EA stimulation (2Hz, 0.07 mA, 0.3ms)을 침치료 방법으로 적용하였다. 전침의 진통기전을 확인하기 위하여, ${\alpha}1$-adrenergic antagonist (prazosin, 1 mg/kg, i.p.), ${\alpha}2$-adrenergic receptor antagonist (yohimbine, 2mg/kg, i.p.), ${\alpha}1$-adrenergic receptor agonist(phenylephrine, 2mg/kg, i.p.), ${\alpha}2$-adrenergic receptor agonist(clonidine, $40{\mu}g$/kg, i.p.)을 전침시행 20분 전에 복강 내로 전처치하였다. Tail flick unit(Ugo Basile Model 7360)을 이용하여 열자극에 대한 통증역치를 측정하였다. 결과 : 퇴행성관절염 징후(gross, histopathological features)와 통증역치의 변화가 최대값을 나타내는 CIA 유발 4주차에 저빈도 전침자극(train pulse, 2Hz, 0.07mA, 0.3ms)을 족삼리($ST_{36}$)에 적용하였으며, 족삼리 전침의 진통효과는 ${\alpha}2$-adrenergic receptor antagonist(yohimbine, 2mg/kg, i.p.)전처치에 의해 억제되었으나, ${\alpha}1$-adrenergic antagonist(prazosin, 1 mg/kg, i.p.)전처치에는 억제되지 않았다. 또 ${\alpha}2$-adrenergic receptor agonist(clonidine, $40{\mu}g$/kg, i.p.)의 전처치를 통하여 유의한 synergistic analgesic effect가 관찰되었으나, ${\alpha}1$-adrenergic receptor agonist(phenylephrine, 2mg/kg, i.p.)의 전처치는 전침의 진통효과에 synergistic effect를 미치지 않는 것으로 나타났다. 결론 : 저빈도 족삼리 전침은 CIA로 유발된 염증성 통증에 대하여 진통효과를 발휘하며, 이는 ${\alpha}2$-adrenergic receptor에 의하여 매개되는 것으로 보이며 ${\alpha}1$-adrenergic receptor는 영향을 미치지 않는 것으로 사료된다.

Ginsenoside Rg3 protects against iE-DAP-induced endothelial-to-mesenchymal transition by regulating the miR-139-5p-NF-κB axis

  • Lee, Aram;Yun, Eunsik;Chang, Woochul;Kim, Jongmin
    • Journal of Ginseng Research
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    • v.44 no.2
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    • pp.300-307
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    • 2020
  • Background: Emerging evidence suggests that endothelial-to-mesenchymal transition (EndMT) in endothelial dysfunction due to persistent inflammation is a key component and emerging concept in the pathogenesis of vascular diseases. Ginsenoside Rg3 (Rg3), an active compound from red ginseng, has been known to be important for vascular homeostasis. However, the effect of Rg3 on inflammation-induced EndMT has never been reported. Here, we hypothesize that Rg3 might reverse the inflammation-induced EndMT and serve as a novel therapeutic strategy for vascular diseases. Methods: EndMT was examined under an inflammatory condition mediated by the NOD1 agonist, γ-d-glutamyl-meso-diaminopimelic acid (iE-DAP), treatment in human umbilical vein endothelial cells. The expression of EndMT markers was determined by Western blot analysis, real-time polymerase chain reaction, and immunocytochemistry. The underlying mechanisms of Rg3-mediated EndMT regulation were investigated by modulating the microRNA expression. Results: The NOD1 agonist, iE-DAP, led to a fibroblast-like morphology change with a decrease in the expression of endothelial markers and an increase in the expression of the mesenchymal marker, namely EndMT. On the other hand, Rg3 markedly attenuated the iE-DAP-induced EndMT and preserved the endothelial phenotype. Mechanically, miR-139 was downregulated in cells with iE-DAP-induced EndMT and partly reversed in response to Rg3 via the regulation of NF-κB signaling, suggesting that the Rg3-miR-139-5p-NF-κB axis is a key mediator in iE-DAP-induced EndMT. Conclusion: These results suggest, for the first time, that Rg3 can be used to inhibit inflammation-induced EndMT and may be a novel therapeutic option against EndMT-associated vascular diseases.

A Study for GnRH Antagonist (Cetrotide) Short Protocol in Controlled Ovarian Hyperstimulation (GnRH Antagonist (Cetrotide) Short Protocol의 임상적 유용성에 관한 연구)

  • Kim, Moon-Young;Jung, Byeong-Jun
    • Clinical and Experimental Reproductive Medicine
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    • v.28 no.4
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    • pp.265-270
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    • 2001
  • Objective : The aim of this study was to evaluate the outcome the GnRH antagonist (Cetrotide) short protocol in controlled ovarian hyperstimulation comparing with GnRH agonist long protocol. Materials and Method: From July 2000 to November 2001, 26 patients, 28 cycles were performed in controlled ovarian hyperstimulation by GnRH antagonist and GnRH agonist. GnRH antagonist (Cetrotide) was administered in 12 patients (14 cycles, Group 1) and GnRH agonist (Lucrin, Sub Q, Group 2) in 14 patients (14 cycles). Ovulation induction was performed by hMG (Pergonal) in group 1, and by Combo (Metrodine HP + Pergonal) in group 2. We compared the fertilization rate, good quality embryo, and clinical pregnancy rate between the two groups. Student-t test and Chi-square were used to determine statistical significance. Statistical significance was defined as p<0.05. Results: Ovarian hyperstimulation syndrome did not occurred in which estradiol (E2) level was $3874{\pm}809\;pg/ml$ and the number of retrieved oocytes was $18.4{\pm}2.4$. The number of used gonadotropin ampules was significantly decreased in Group 1 (26.0 vs. 33.1, p<0.04). There were no significant difference in the number of preovulatory oocyte ($10.6{\pm}6.9$ vs. $10.0{\pm}6.1$), fertilization rate ($74.8{\pm}23.4$ vs. $72.2{\pm}21.8$), good quality embryo ($58.7{\pm}23.6$ vs. $38.7{\pm}36.6$), and embryo transfer ($4.3{\pm}1.6$ vs. $4.4{\pm}1.6$). Although the age of the group 1 was older than the group 2 (34.4 vs. 30.8), there was no significant difference in clinical pregnancy rate (50.0% vs. 57.1%). Conclusions: We suggest that GnRH antagonist was a safe, effective, and alternative method in the controlled ovarian hyperstimulation, especially in PCOD patients who will be develop the ovarian hyperstimulation syndrome.

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Biapigenin, Candidate of an Agonist of Human Peroxisome Proliferator-Activated Receptor γ with Anticancer Activity

  • Kim, Jin-Kyoung;Shin, So-Young;Lee, Jee-Young;Lee, So-Jung;Lee, Eun-Jung;Jin, Qinglong;Lee, June-Young;Woo, Eun-Rhan;Lee, Dong-Gun;Yoon, Do-Young;Kim, Yang-Mee
    • Bulletin of the Korean Chemical Society
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    • v.32 no.8
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    • pp.2717-2721
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    • 2011
  • Peroxisome proliferator-activated receptors (PPARs) are a subfamily of nuclear receptors (NRs). Human peroxisome proliferator-activated receptor gamma (hPPAR${\gamma}$) has been implicated in the pathology of numerous diseases, including obesity, diabetes, and cancer. ELISA-based hPPAR${\gamma}$ activation assay showed that biapigenin increased the binding between hPPAR${\gamma}$ and steroid receptor coactivator-1 (SRC-1) by approximately 3-fold. In order to confirm that biapigenin binds to hPPAR${\gamma}$, fluorescence quenching experiment was performed. The results showed that biapigenin has higher binding affinity to hPPAR${\gamma}$ at nanomolar concentrations compared to indomethacin. Biapigenin showed anticancer activity against HeLa cells. Biapigenin was noncytotoxic against HaCa T cell. All these data implied that biapigenin may be a potent agonist of hPPAR${\gamma}$ with anticancer activity. We will further investigate its anticancer effects against human cervical cancer.

The Role of Adenosine Receptors on Acetylcholine Release in the Rat Hippocampus (흰쥐 해마에서 Acetylcholine 유리에 미치는 Adenosine 수용체의 역할)

  • Choi, Bong-Kyu;Kim, Do-Kyung
    • The Korean Journal of Pharmacology
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    • v.30 no.2
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    • pp.145-152
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    • 1994
  • As it has been reported that the depolarization induced acetylcholine(ACh) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor and various lines of evidence indicate the $A_2-receptor$ is present In hippocampus, this study was undertaken to delineate the role of adenosine receptors on hippocampal ACh release. Slices from the rat hippocampus were equilibrated with $[^3H]-choline$ and the release of the labelled product, $[^3H]-ACh$, which evoked by electrical stimulation(3 Hz, $5\;Vcm^{-1}$, 2 ms, rectangular pulses) was measured, and the influence of various agents on the evoked tritium outflow was Investigated. Adenosine$(0.3{\sim}100\;{\mu}M)$ and CPA$(0.1{\sim}30\;{\mu}M)$ decreased the $[^3H]-ACh$ release in a dose-dependent manner without changing the basal rate of release. DPCPX$(1{\sim}10\;{\mu}M)$, a selective $A_1-receptor$, antagonist, increased the $[^3H]-ACh$ release in a dose related fashion with slight increase of basal tritium release. And the effects of adenosine and CPA were significantly inhibited by $DPCPX(2\;{\mu}M)$ treatment. CPCA, a specific $A_2-agonist$, in concentration ranging from 0.3 to 30 ${\mu}M$, decreased the evoked tritium outflow, and these effects were also abolished by $DPCPX(2\;{\mu}M)$ treatment. But the CPCA effects were not affected by $DMPX(2\;{\mu}M)$, a specific Aa-antagonist, treatment. However, CGS 21680c, a recently introduced potent $A_2-agonist$, in concentration ranging from 0.1 to $10{\mu}M$, did not alter the evoked tritium outflow. These results indicate that the decrement of the evoked ACh release by adenosine is mediated by $A_1-heteroreceptor$, but $A_2-adenosine$ receptor is not involved in ACh release in the rat hippocampus.

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RGS3 Suppresses cAMP Response Element (CRE) Activity Mediated by CB2 Cannabinoid Receptor in HEK293 Cells (캐너비노이드 수용체 CB2의 신호전달작용에 미치는 RGS3의 억제적 효과)

  • Kim, Sung-Dae;Lee, Whi-Min;Endale, Mehari;Cho, Jae-Youl;Park, Hwa-Jin;Oh, Jae-Wook;Rhee, Man-Hee
    • Journal of Life Science
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    • v.19 no.11
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    • pp.1506-1513
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    • 2009
  • RGS proteins have been identified as negative regulators of G protein signalling pathways and attenuate the activity of GPCR receptors. However, information on the regulatory effects of RGS proteins in the activity of cannabinoid receptors is limited. In this study, the role of RGS proteins on the signal transduction of the CB2 cannabinoid receptor was investigated in HEK293 cells co-transfected with CB2-receptors and plasmids encoding RGS2, RGS3, RGS4 and RGS5. Treatment of cells with WIN55, 212-2, a CB2 receptor agonist, inhibited forskolin-induced cAMP response element (CRE) activity in CB2-transfected HEK293 (CB2-HEK293) cells. This inhibitory effect of WIN 55, 212-2 on CRE activity was reversed by co-transfection of CB2-HEK293 cells with RGS3, but not with RGS2, RGS4 and RGS5. However, endogenous RGS3 protein knocked down by a small interfering siRNA targeting RGS3 gene enhanced inhibition of forskolin induced CRE activity via agonist induced CB2 receptor signal transduction. These results indicate the functional role of endogenous RGS protein in cannabinoid signaling pathways and define receptor-selective roles of endogenous RGS3 in modulating CRE transcriptional responses to agonist induced CB2 receptor activity.

Effects of KATP Channel Blocker, cAMP and cGMP on the Cardiovascular Response of Adenosine A1 Agonist in the Spinal Cord of the Rats

  • Shin In-Chul
    • Biomolecules & Therapeutics
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    • v.14 no.2
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    • pp.119-124
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    • 2006
  • This study was performed to investigate the influence of the spinal adenosine $A_1$ receptors on the central regulation of blood pressure (BP) and heart rate (HR), and to define whether its mechanism is mediated by cyclic AMP (cAMP), cyclic GMP (cGMP) or potassium channel. Intrathecal (i.t.) administration of drugs at the thoracic level were performed in anesthetized, artificially ventilated male Sprague-Dawley rats. I.t. injection of adenosine $A_1$ receptor agonist, $N^6$-cyclohexyladenosine (CHA; 1, 5 and 10 nmol) produced dose dependent decrease of BP and HR and it was attenuated by pretreatment of 50 nmol of 8-cyclopentyl-1,3-dimethylxanthine, a specific adenosine $A_1$ receptor antagonist. Pretreatment with a cAMP analogue, 8-bromo-cAMP, also attenuated the depressor and bradycardiac effects of CHA (10 nmol), but not with cGMP analogue, 8-bromo-cGMP. Pretreatment with a ATP-sensitive potassium channel blocker, glipizide (20 nmol) also attenuated the depressor and bradycardiac effects of CHA (10 nmol). These results suggest that adenosine $A_1$ receptor in the spinal cord plays an inhibitory role in the central cardiovascular regulation and that this depressor and bradycardiac actions are mediated by cAMP and potassium channel.

Pharmacological Effects of KR60886, A New β3 Adrenoceptor Agonist

  • Lee, Sang-Suk;Yang, Sung-Don;Ha, Jae-Du;Choi, Joong-Kwon;Cheon, Hyae-Gyeong
    • Biomolecules & Therapeutics
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    • v.12 no.4
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    • pp.215-220
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    • 2004
  • In an attempt to develop new anti-diabetic agents, a series of aryloxypropanolamine derivatives was synthesized to serve as ${\beta}_3$ adrenoceptor agonists. Among these derivatives, 1-{1-methyl-3-[4-(2-methyl-2H-1,2,3,4-tetrazol-5-yl)phenyl]propylamino}-3-phenoxy-2-propanol (KR60886) possessed a high affinity for the ${\beta}_3$ adrenoceptor (Ki = 28 nM) and moderate affinities for ${\beta}_1$ and ${\beta}_2$ adrenoceptors (Ki = 95 nM and 100 nM, respectively). In addition, KR60886 stimulated cAMP production with an EC$_{50}$ of 0.4 ${\mu}M$, confirming its agonistic activity for the ${\beta}_3$ adrenoceptor. In vivo activities of KR60886 were examined by using a fat-fed/streptozotocin (STZ)-treated rat model and the ob/ob mouse model. Oral administration of KR60886 (10 mg/kg) for 3 days (b.i.d.) to fat-fed/STZ-treated rats significantly lowered plasma glucose levels and reduced plasma free fatty acid concentrations. Similarly, KR60886 treatment (10 mg/kg/day for 7 d) resulted in a reduction of plasma glucose concentrations in ob/ob mice. The present study suggests that KR60886 is a potent ${\beta}_3$ receptor agonist with in vivo anti-diabetic properties.

Extracellular Acidification Augments NLRP3-Mediated Inflammasome Signaling in Macrophages

  • Byeong Jun Chae;Kyung-Seo Lee;Inhwa Hwang;Je-Wook Yu
    • IMMUNE NETWORK
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    • v.23 no.3
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    • pp.23.1-23.17
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    • 2023
  • Inflammation is a series of host defense processes in response to microbial infection and tissue injury. Inflammatory processes frequently cause extracellular acidification in the inflamed region through increased glycolysis and lactate secretion. Therefore, the immune cells infiltrating the inflamed region encounter an acidic microenvironment. Extracellular acidosis can modulate the innate immune response of macrophages; however, its role for inflammasome signaling still remains elusive. In the present study, we demonstrated that macrophages exposed to an acidic microenvironment exhibited enhanced caspase-1 processing and IL-1β secretion compared with those under physiological pH. Moreover, exposure to an acidic pH increased the ability of macrophages to assemble the NLR family pyrin domain containing 3 (NLRP3) inflammasome in response to an NLRP3 agonist. This acidosis-mediated augmentation of NLRP3 inflammasome activation occurred in bone marrow-derived macrophages but not in bone marrow-derived neutrophils. Notably, exposure to an acidic environment caused a reduction in the intracellular pH of macrophages but not neutrophils. Concordantly, macrophages, but not neutrophils, exhibited NLRP3 agonist-mediated translocation of chloride intracellular channel protein 1 (CLIC1) into their plasma membranes under an acidic microenvironment. Collectively, our results demonstrate that extracellular acidosis during inflammation can increase the sensitivity of NLRP3 inflammasome formation and activation in a CLIC1-dependent manner. Thus, CLIC1 may be a potential therapeutic target for NLRP3 inflammasome-mediated pathological conditions.

EFFECTS OF XYLAZINE (ALPHA 2-ADRENERGIC AGONIST) ON THE STRESS RESPONSE TO IMMOBILIZATION AND HEAT IN RATS

  • Fayed, A.H.;Zakaria, A.D.;Hedaya, S.A.;El-Ashmawy, I.M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.7 no.3
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    • pp.397-400
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    • 1994
  • The effect of xylazine administration on plasma cortisol, prolactin, glucose and packed cell volume (PCV) responses to immobilization and heat stress was investigated. Immobilization of rats for 2 hours by ligation of the fore and hind legs strongly caused approximately two-fold increase in plasma cortisol and prolactin levels. Plasma glucose and PCV were not significantly changed. Pretreatment of immobilized rats with xylazine (20 mg/kg body weight i.m.) resulted in approximately 20% reduction in both plasma cortisol and prolactin concentrations. A marked hyperglycemia and increase in the PCV value was observed. On the other hand, rats exposed to acute heat stress ($40^{\circ}C$, and 60% relative humidity) for 2 hours, also developed two fold increase in both plasma cortisol and prolactin concentrations and the pretreatment with xylazine caused a 20% reduction in the levels of both hormones. Plasma glucose level was not significantly changed in heat stressed rats but it was markedly increased after pretreatment with xylazine. PCV was significantly incrcased under heat stress and pretreatment with xylazine induced a pronounced elevation in this value. It was suggested that stimulation of cortisol and prolactin secretion in response to immobilization or heat stress can be partially reduced by an alpha 2-adrenergic agonist.