• Preventive Nutrition and Food Science
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• 제6권1호
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• pp.43-50
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• 2001

The effects of cardiac ischemia-reperfusion and $\beta$-adrenergic stimulation on metabolic function and energetics were investigated in Lan gendorff-perfused spontaneously hypertensive rat (SHR) hearts. Sarcoplasmic reticulum {TEX}$Ca^{2+}${/TEX}-dependent ATPase and cardiac lactate dehydrogenase (LDH) are additionally studied. The perfusion medium (1.0 mM {TEX}$Ca^{2+}${/TEX}) contained 5 mM glucose(+5 U/L insulin) and 2 mM pyruvate as substrates. Global ischemia was induced by reducing perfusion pressure of 100 to 40 cm {TEX}$H_{2}${/TEX}O, followed by 20 min reperfusin. Isoproterenol (ISO, 1$\mu$M) was infused for 10 min. Coronary vascular resistance and myocardial oxygen consumption ({TEX}$MVO_{2}${/TEX}) of SHR were increased in parallel with enhanced venous lactate during ischemia and reperfusion compared to those of Sprague Dawley (SD) hearts. Although ischemia-induced increase in venous lactate and combined adenosine plus inosine was abolished, coronary vasodilation produced in SD during reperfusion. In SHR, depressed reactive hyperemia was associated with a fall in cardiac ATP and CrP/Pi ratio and a rise in intracellular lactate/Pyruvate ratio. On the other hand, ISO produced coronary functional hyperemia and an increase in {TEX}$MVO_{2}${/TEX}. However, these responses were less than those in SHR hearts. The ATPase activity of SHR was attenuated in free {TEX}$Ca^{2+}${/TEX} concentrations used under basal condition and with ISO compared to that of SD. Venous lactate output and cardiac LDH activity were augmented in SHR as influenced by ISO. These results demonstrate that coronary reactive and functional hyperemia was dpressed in SHR, which cold be explained by alterations in the cytosolic phosphorylation potential and the cytosolic redox state manipulated by LDH, and by abnormal free calcium handling.

• Biomolecules & Therapeutics
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• 제4권1호
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• pp.97-102
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• 1996

To investigate whether human $\beta$$_2$-adrenergic receptor devoid of the C-terminal two transmembrane helices retain its ligand binding activity and specificity, 5'780-bp DNA fragment of the receptor gene which encodes amino acid 1-260 of human $\beta$$_2$-adrenergic receptor was subcloned into the bacterial fusion protein expression vector and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was expressed as a membrane bound form which was verified by SDS-PAGE and Western blot. The fusion protein expressed in this study specifically bound $\beta$-adrenergic receptor ligand [$^3$H] Dihydroalprenolol. In saturation ligand binding assay, the $K_{d}$ value was 7.6 nM which was similar to that of intact $\beta$$_2$-adrenergic receptor in normal animal tissue ( $K_{d}$=1~2 nM) and the $B_{max}$ value was 266 fmol/mg membrane protein. In competition binding assay, the order of binding affinity of various adrenergic receptor agonists to the fusion protein was isoproterenol》epinephrine norepinephrine, which was similar to that of intact receptor in normal animal tissue. These results suggest that N-terminal five transmembrane helices of the $\beta$$_2$-adrenergic receptor be sufficient to determine the ligand binding activity and specificity, irrespective of the presence or absence of the C-terminal two transmembrane helices.s.s.s.

• 대한수의학회지
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• 제14권1호
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• pp.33-40
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• 1974

It has been generally understood that the intestinal tracts are under the control of the autonomic nerves; the parasympathetics are excitatory and the sympathetics inhibitory. However, it is recently reported that the actions of these autonomic nerves in the newborn animals are shown to be different from those in the adult animals in some species. In order to elucidate the role of sympathetic innervation to the intestinal tracts, the effects of periarterial nerve stimulation were studied in the periarterial sympathetics-jejunum preparations of the chick and the effects of some autonomic drugs on the isolated muscle strips were also studied. The results obtained were as follows: 1. The periarterial stimulation in the periarterial sympathetics-jejunum preparation elicited the responses of three patterns; 1) contrcation followed by relaxation 2) contraction only 3) relaxation only. The excitatory response was most effective in the stimulus frequencies of 40 cps, whereas the inhibitory response was maximal in the stimulus frequencies of 30 cycle per second. 2. The excitatory response to the periarterial stimulation was not affected by the pretreatment with phenoxybenzamine, dibenamine, propranolol and atropine, whereas the inhibitory response was completely blocked by the pretreatment with phenoxybenzamine and propranolol. 3. In the periarterial syrnpathetics-jejunum preparation treated with reserpine, the periarterial stimulation evoked only contraction, and the contraction was not affected by the pretreatment with phenoxybenzamine, propranolol and atropine. 4. The administration of norepinephrine evoked a relaxation in the isolated jejunum muscle strips and the effect was completely blocked by the pretreatment with phenoxybenzamine. 5. The administration of isoproterenol produced a relaxation in the isolated jejunum muscle strips and the effect was not affected by pretreatment with phenoxybenzamine, whereas the effect was completely blocked by the pretratment with propranolol. 6) The administration of acetylcholine produced a marked contraction in the isolated jejunum muscle strips and the effect was completely abolished by the pretreatment of atropine. These experimental evidences indicate that the inhibitory response to the periarterial stimulation is due to adrenergic fibers and the excitatory response is due to neither adrenergic nor cholinergic component.

• The Korean Journal of Physiology and Pharmacology
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• 제5권6호
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• pp.487-494
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• 2001

During depolarization, extrusion of $Ca^{2+}$ from sarcoplasmic reticulum through forward-mode $Na^+-Ca^{2+}$ exchange was studied in the rat ventricular myocytes patch-clamped in whole-cell configuration. In order to confine the $Ca^{2+}$ responses in a micro-domain by limiting the $Ca^{2+}$ diffusion time, rat ventricular myocytes were dialyzed with high (14 mM) EGTA. $K^+$ current was suppressed by substituting KCl with 105 mM CsCl and 20 mM TEA in the pipette filling solution and by omitting KCl in the external Tyrode solution. $Cl^-$ current was suppressed by adding 0.1 mM DIDS in the external Tyrode solution. During stimulation roughly mimicking action potential, the initial outward current was converted into inward current, $47{\pm}1%$ of which was suppressed by 0.1 mM $CdCl_2.$ 10 mM caffeine increased the remaining inward current after $CdCl_2$ in a cAMP-dependent manner. This caffeine-induced inward current was blocked by $1\;{\mu}M$ ryanodine, $10\;{\mu}M$ thapsigargin, 5 mM $NiCl_2,$ or by $Na^+\;and\;Ca^{2+}$ omission, but not by $0.1\;{\mu}M$ isoproterenol. The $I{\sim}V$ relationship of the caffeine-induced current elicited inward current from -45 mV to +3 mV with the peak at -25 mV. Taken together, it is concluded that, during activation of the rat ventricular myocyte, forward-mode $Na^+-Ca^{2+}$ exchange extrudes a fraction of $Ca^{2+}$ released from sarcoplasmic reticulum mainly by voltage-sensitive release mechanism in a micro-domain in the t-tubule, which is functionally separable from global $Ca^{2+}{_i}$ by EGTA.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.977-983
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• 2006

The objective was to devise an animal model of myocardial infarction (MI) against which cardioprotective drugs might be tested. We describe the effects of nimesulide, a COX experience with development and validation of such a model. The rabbit was chosen in preference to rodents because its heart and cardiac circulation more closely resemble those of human. Thus, the cardiovascular system of anaesthetized male rabbits, 1 to 1.5 kg (n=11), was stressed by a single bolus intravenous injection of isoprenaline (ISP), 65 mg/kg. The effects of the injection were followed for sixteen days and were evaluated in four ways: 1) measurements of creatinine kinase isozyme and troponin-I (TPI) in serum 2) Electrocardiographic (ECG) changes (ST elevation and Q wave development) 3) Cardiac histopathology observed in tissue sections of the isolated of the heart. The histopathological analysis showed that rabbit heart on 2nd day after ISP injection showed changes of coagulation necrosis. Day 4 total coagulation with the loss of nuclear and striation associated with heavy interstitial infiltrate of neutrophils was found. Day 8 after infarction showed collagen deposition with capillary channels in between the remaining islands of myocytes in the infarcted area. On the 16th day scarring was complete. Coronary perfusion rates (CPR) and heart rate (HR) of the infarcted and nimesulide (a COX-2 inhibitor) treated rabbits displayed significant improvement (n=11) on each corresponding day after infarction as compared to the infarcted and saline treated rabbits (P<0.05). All four indices revealed similarities with effects commonly associated with MI in humans.

• The Korean Journal of Physiology and Pharmacology
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• 제25권6호
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• pp.533-543
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• 2021

Myocardial fibrosis (MF) is the result of persistent and repeated aggravation of myocardial ischemia and hypoxia, leading to the gradual development of heart failure of chronic ischemic heart disease. Triptolide (TPL) is identified to be involved in the treatment for MF. This study aims to explore the mechanism of TPL in the treatment of MF. The MF rat model was established, subcutaneously injected with isoproterenol and treated by subcutaneous injection of TPL. The cardiac function of each group was evaluated, including LVEF, LVFS, LVES, and LVED. The expressions of ANP, BNP, inflammatory related factors (IL-1β, IL-18, TNF-α, MCP-1, VCAM1), NLRP3 inflammasome factors (NLRP3, ASC) and fibrosis related factors (TGF-β1, COL1, and COL3) in rats were dete cted. H&E staining and Masson staining were used to observe myocardial cell inflammation and fibrosis of rats. Western blot was used to detect the p-P65 and t-P65 levels in nucleoprotein of rat myocardial tissues. LVED and LVES of MF group were significantly upregulated, LVEF and LVFS were significantly downregulated, while TPL treatment reversed these trends; TPL treatment downregulated the tissue injury and improved the pathological damage of MF rats. TPL treatment downregulated the levels of inflammatory factors and fibrosis factors, and inhibited the activation of NLRP3 inflammasome. Activation of NLRP3 inflammasome or NF-κB pathway reversed the effect of TPL on MF. Collectively, TPL inhibited the activation of NLRP3 inflammasome by inhibiting NF-κB pathway, and improved MF in MF rats.

• BMB Reports
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• 제54권8호
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• pp.419-424
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• 2021

Cold-induced norepinephrine activates β3-adrenergic receptors (β3-AR) to stimulate the kinase cascade and cAMP-response element-binding protein, leading to the induction of thermogenic gene expression including uncoupling protein 1 (Ucp1). Here, we showed that stimulation of the β3-AR by its agonists isoproterenol and CL316,243 in adipocytes increased the expression of Ucp1 and Heme Oxygenase 1 (Hmox1), the principal Nrf2 target gene, suggesting the functional interaction of Nrf2 with β3-AR signaling. The activation of Nrf2 by tert-butylhydroquinone and reactive oxygen species (ROS) production by glucose oxidase induced both Ucp1 and Hmox1 expression. The increased expression of Ucp1 and Hmox1 was significantly reduced in the presence of a Nrf2 chemical inhibitor or in Nrf2-deleted (knockout) adipocytes. Furthermore, Nrf2 directly activated the Ucp1 promoter, and this required DNA regions located at -3.7 and -2.0 kb of the transcription start site. The CL316,243-induced Ucp1 expression in adipocytes and oxygen consumption in obese mice were partly compromised in the absence of Nrf2 expression. These data provide additional insight into the role of Nrf2 in β3-AR-mediated Ucp1 expression and energy expenditure, further highlighting the utility of Nrf2-mediated thermogenic stimulation as a therapeutic approach to diet-induced obesity.

• 동의생리병리학회지
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• 제38권1호
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• pp.10-15
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• 2024

Previous studies have highlighted the pivotal role of the β-adrenergic receptor (β-AR) signaling pathway in stimulating cancer metastasis induced by chronic stress. According to the theory of traditional Korean medicine, chronic stress can induce Qi stagnation. Based on the traditional role of premature citrus unshiu peel in moving Qi, we hypothesized that an ethanol extract of premature citrus unshiu peel (EPCU) can attenuate chronic stress-induced cancer progression. In this study, we investigated the potential role of EPCU on modulating the adrenergic agonists-induced metastatic properties of liver cancer cells. Our findings revealed that adrenergic agonists, including norepinephrine (NE), epinephrine (E), and isoproterenol (ISO), augmented the migratory capacity of Hep3B human hepatocellular carcinoma cells, which was completely abrogated by EPCU treatment in a concentration-dependent manner. Consistently, EPCU inhibited the E-induced invasive property of Hep3B cells in a dose-dependent manner. These results suggest that EPCU efficiently attenuates adrenergic agonists-induced metastatic abilities of liver cancer cells. As a molecular mechanism, EPF suppressed the phosphorylation of major components of β-AR signaling pathway, including Src, signal transducer and activator of transcription 3 (STAT3) and ERK, induced by E treatment. Taken together, our results demonstrate that EPCU impedes the adrenergic agonists-driven metastatic potential of cancer cells by inhibiting β-AR signaling pathway. This study provides basic evidence supporting the probable use of premature citrus unshiu peel to prevent metastasis in liver cancer patients under chronic stress.

• 대한약리학회지
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• 제22권1호
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• pp.24-33
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• 1986

본 연구에서는 개구리(Rana nigromaculata)의 피부에 있어서 전위차(PD), 단락전류(SCC) 및 total skin conductance(TSC)에 미치는 제종 adrenergic agonist 및 그 차단제의 영향을 관찰하여 개구리 피부에 adrenoceptors의 존재를 확인하고 Na 수송에 있어 그들의 역할을 구명코자 하였다. 1.Norepinephrine(NE, $6{\times}10^{-8}-6{\times}10^{-5}M$), phenylephrine($PE,5{\times}10^{-6}-5{\times}10^{-4}M$)의 PD 및 epinephrine(Epi, $5.5{\times}10^{-7}-5.5{\times}10^{-5}M$)의 PD 및 SCC 증가효과는 약물의 투여농도에 비례하였으며, Epi의 최대효과는 NE나 PE의 것보다 약하였다. 2. 이러한 PD 및 SCC의 증가효과는 alpha 1 adrenoceptor 차단체인 prazosin $2{\times}10^{-6}M$에 의해서 억제되었으며, 특히 Epi의 증가효과는 불가역성 alpha receptor 차단제인 phenoxybenzamine $3.3{\times}10^{-5}M$에 의하여 완전히 차단되며 대량의 Epi에 의해서는 PD 및 SCC의 감소를 초래하였다. 3. Beta adrenoceptor agonist인 isoproterenol$(5{\times}10^{-7}-5{\times}10^{-6}M)$에 의해 농도증가에 비례한 PD 및 SCC의 감소가 일어났으며, 이는 선택적 bete receptor 차단제인 propranolol $4{\times}10^{-6}M$에 의해 차단되었다. 또한 Epi의 PD 및 SCC 증가효과는 propranolol $4{\times}10M$에 의하여 강화됨을 볼 수 있었다. 4. Alpha 2 adrenoceptor agonist인 clonidine 및 guanabenz도 PD 및 SCC의 증가를 가져왔으며 이러한 효과는 alpha 2 receptor 차단제인 yohimbine에서 보다 Alpha 1 receptor 차단제인 prazosin에 의해 더 잘 억제되었다. 이상 실험의 결과 개구리 복부피부에도 포유동물에서와 같이 adrenergic alpha 및 beta receptor가 존재하며 alpha receptor는 PD 및 SCC의 증가를, beta receptor는 PD 및 SCC의 감소를 매개하여, 개구리 피부의 Na 수송에 있어 adrenergic system이 중요한 조절작용을 하고 있음을 알 수 있었다. 그러나 여기에 관여하는 alpha receptor는 다른 포유류에서와 같이 alpha 1 및 alpha 2 adrenoceptor로 구분할 수는 없었다.

• 대한약리학회지
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• 제14권1_2호
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• pp.33-40
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• 1978

1. guinea-pig 요관(尿管) 평골근(平滑筋)의 수축(收縮) 및 이완반응(弛緩反應) 연령이 증가(增加)에 의(依)하여 크게 영향(影響)을 받는다는 사실(事實)을 관찰(觀察)하였다. 2. 2-3주, 3개월 및 2-3년 guinea-pig 요관(尿管)을 적출하고 Tyrode 액내(液內)에서 train stimulation법(法)으로 일정(一定)하게 수축반응(收縮反應)을 일으킨다. 3. $Ca^{++}$-free Tyrode 액(液)에서 전기자극(電氣刺戟) 반응(反應)이 소실(消失)된 후(後) $Ca^{++}$ 함유(含有) Tyrode 액(液)을 가(加)하여 야기(惹起)되는 수축반응(收縮反應)의 회복(恢復)에는 3개월(個月) 및 2-3년(年) 요관(尿管)에 비(比)하여 2-3주(週) 요관(尿管)은 훨씬 낮은 농도(濃度)의 $Ca^{++}$을 필요(必要)로 하였으며 비록 2.7mM $Ca^{++}$을 가(加)하여도 2-3주(週) 및 3개월(個月) 요관에 있어서는 처음 수축고의 90% 이상을 회복하였으나 2-3년(年) 요관(尿管)에서는 77.2%만 회복하였다. 4. ISP는 2-3년 요관(尿管)에 비(比)하여 2-3주(適) 요관(尿管)에 있어서 수축고의 억제(抑制) 효과(效果)가 유의(有意)하게 강(强)하였고 theophylline은 연령(年齡)에 관계없이 양군(兩群)모두 강력(强力)히 억제작용(抑制作用)을 나타내었다. 5. 2-3주 뇨관의 수축에 대하여 dibutyryl cyclic AMP는 dose-dependent하게 억제를 나타내었으나 2-3년 노요관(老尿管)에 있어서는 이와같은 현상은 없었다. 그리고 요관(尿管)조직내 cyclic AMP 함량(含量)은 2주기니픽 뇨관에서는 17개월 뇨관에 비(比)하여 73%의 높은 농도를 나타내었고 cyclic GMP의 함량(含量)은 큰 차이를 볼 수 없었다. 6. 유년(幼年) 요관평골근(尿管平滑筋)은 노요관(老尿管)에 비(比)하여 근수축(筋收縮) 및 이완(弛緩)에 관여(關與)하는 $Ca^{++}$의 동원(動員) 및 저장(貯藏)에 있어서 높은 효율성(效率性)을 가지고 있다고 사료(思料)되는 바이다.