• Molecules and Cells
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• 제19권3호
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• pp.402-407
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• 2005

Bone marrow mesenchymal stem cells (MSCs) have shown potential for cardiac repair following myocardial injury, but this approach is limited by their poor viability after transplantation. To reduce cell loss after transplantation, we introduced the fibroblast growth factor-2 (FGF-2) gene ex vivo before transplantation. The isolated MSCs produced colonies with a fibroblast-like morphology in 2 weeks; over 95% expressed CD71, and 28% expressed the cardiomyocyte-specific transcription factor, Nkx2.5, as well as ${\alpha}$-skeletal actin, Nkx2.5, and GATA4. In hypoxic culture, the FGF-2-transfected MSCs (FGF-2-MSCs) secreted increased levels of FGF-2 and displayed a threefold increase in viability, as well as increased expression of the anti-apoptotic gene, Bcl2, and reduced DNA laddering. They had functional adrenergic receptors, like cardiomyocytes, and exposure to norepinephrine led to phosphorylation of ERK1/2. Viable cells persisted 4 weeks after implantation of $5.0{\times}10^5$ FGF-2-MSCs into infarcted myocardia. Expression of cardiac troponin T (CTn T) and a voltage-gated $Ca^{2+}$ channel (CaV2.1) increased, and new blood vessels formed. These data suggest that genetic modification of MSCs before transplantation could be useful for treating myocardial infarction and end-stage cardiac failure.

• Molecules and Cells
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• 제20권3호
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• pp.305-314
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• 2005

Investigation of chemically synthesized inositol 1,4,5-trisphosphate [$Ins(1,4,5)P_3$] analogs has led to the isolation of a novel binding protein with a molecular size of 130 kDa, characterized as a molecule with similar domain organization to phospholipase C-${\delta}1$ (PLC-${\delta}1$) but lacking the enzymatic activity. An isoform of the molecule was subsequently identified, and these molecules have been named PRIP (PLC-related, but catalytically inactive protein), with the two isoforms named PRIP-1 and -2. Regarding its ability to bind $Ins(1,4,5)P_3$ via the pleckstrin homology domain, the involvement of PRIP-1 in $Ins(1,4,5)P_3$-mediated $Ca^{2+}$ signaling was examined using COS-1 cells overexpressing PRIP-1 and cultured neurons prepared from PRIP-1 knock-out mice. Yeast two hybrid screening of a brain cDNA library using a unique N-terminus as bait identified GABARAP ($GABA_A$ receptor associated protein) and PP1 (protein phosphatase 1), which led us to examine the possible involvement of PRIP in $GABA_A$ receptor signaling. For this purpose PRIP knock-out mice were analyzed for $GABA_A$ receptor function in relation to the action of benzodiazepines from the electrophysiological and behavioral aspects. During the course of these experiments we found that PRIP also binds to the b-subunit of $GABA_A$ receptors and PP2A (protein phosphtase 2A). Here, we summarize how PRIP is involved in $Ins(1,4,5)P_3$-mediated $Ca^{2+}$ signaling and $GABA_A$ receptor signaling based on the characteristics of binding molecules.

• 한국축산식품학회지
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• 제26권3호
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• 대한한의학회지
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• 제29권5호
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• pp.29-40
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• 2008

Objectives : It has been reported that Sophorae Subprostratae Radix (SSR) has a neuroprotective effect on cerebral ischemia in animals. In the present study, the authors investigated the neuroprotective effect of SSR on glutamate excitotoxicity. Glutamate excitotoxicity was induced by using NMDA, AMPA, and KA in PC12 cells and in organotypic hippocampal slice cultures. Methods :Methanolic extract of SSR was added at 0.5, 5, and 50 ${\mu}$g/ml to culture media for 24 hours. The effects of SSR were evaluated by measuring of cell viability, PI-stained neuronal cell death, TUNEL-positive cells, and MAP-2 immunoreactivity. Results : SSR increased PC12 cell viabilities significantly against AMPA-induced excitotoxicity, but not against NMDA-induced or KA-induced excitotoxicity. In organotypic hippocampal slice cultures damaged by NMDA-induced excitotoxicity, SSR attenuated neuronal cell death significantly in the CA1, CA3, and DG hippocampal regions and reduced TUNEL-positive cells significantly in CA1 and DG regions. In organotypic hippocampal slice cultures damaged by AMPA-induced excitotoxicity, SSR attenuated neuronal cell death and reduced TUNEL-positive cell numbers significantly in the CA1 and DG regions. In organotypic hippocampal slice cultures damaged by KA-induced excitotoxicity, SSR attenuated neuronal cell death significantly in CA3, but did not reduce TUNEL-positive cell numbers in CA1, CA3 or DG. In organotypic hippocampal slice cultures damaged by NMDA-induced excitotoxicity, SSR attenuated pyramidal neuron neurite retraction and degeneration in CA1. Conclusions : These results suggest that the neuroprotective effects of SSR are related to antagonistic effects on the NMDA and AMPA receptors of neuronal cells damaged by excitotoxicity and ischemia.

• Journal of Pharmaceutical Investigation
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• 제38권6호
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• pp.413-419
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• 2008

Carvedilol, is a nonselective $\beta$-blocking agent and it also has vasodilating properties that are attributed mainly to its blocking activity at ${\alpha}_1$-receptors. The purpose of the present study was to evaluate the bioequivalence of two carvedilol tablets, $Dilatrend^{(R)}$ tablet 12.5 mg (Chong Kun Dang Pharmaceutical Co., Ltd.) and Cadilan tablet 12.5 mg (KyungDong Pharmaceutical. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of carvedilol from the two carvedilol formulations in vitro was tested using KP VIII Apparatus II method with pH 4.5 dissolution medium. Thirty two healthy male subjects, $25.00{\pm}3.09$ years in age and $70.71{\pm}11.35\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single tablet containing 12.5 mg as carvedilol was orally administered, blood samples were taken at predetermined time intervals and the concentrations of carvedilol in serum were determined using HPLC with fluorescence detector. The dissolution profiles of two formulations were similar in the tested dissolution medium. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, $Dilatrend^{(R)}$ tablet 12.5 mg, were 4.66%, 8.33% and -7.45% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., $\log\;0.9823{\sim}\log\;1.1042$ and $\log\;1.0132{\sim}\log\;1.1875$ for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Cadilan tablet 12.5 mg was bioequivalent to $Dilatrend^{(R)}$ tablet 12.5 mg.

• 대한약리학회지
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• 제29권1호
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• pp.23-32
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• 1993

GABA계가 뇌내의 교감신경계기능에 영향을 주어서 혈압조절에 관여함이 알려져 있다. 본 연구에서는 마취가토에서 GABA계가 두개내압증가에 의한 혈압상승에 관여하는가를 조사하였다. 두개내압증가에 의한 승압은 측뇌실내 muscimol (GABA 작용약)이나 clonidine $({\alpha}_2$-작용약) 전처리후에는 볼 수 없었다. 측뇌실내 yohimbine $({\alpha}_2$-길항약)으로 일으킨 고혈압은 두개내압증가를 하여도 더 이상 상승하지 않았으나, 측뇌실내 bicuculline (GABA 길항약)으로 일으킨 고혈압은 두개내압증가로 더욱 상승하였다. Bicuculline은 muscimol이나 clonidine 저혈압에서는 승압을 일으켰으나 yohimbine이나 두개내압증가에 의한 고혈압에서는 무효였다. Yohimbine은 clonidine 저혈압은 상승시켰으나 muscimol 저혈압에 있어서는 무효였다. Yohimbine은 두개내압증가에 따른 승압상태는 더 올리지 못하였으나 bicuculline 승압상태는 더욱 상승시켰다. Muscimol은 bicuculline과의 길항성이외에 yohimbine 승압을 억제함을 알았으며 yohimbine 승압에 GABA계가 관여함을 추측할 수 있었다. 이러한 실험결과로 두개내압증가에 따른 승압상승은 (1) ${\alpha}_{2}$-수용체, (2) bicuculline-감수성 GABA 수용체, (3) yohimbine-감수성인 clonidine이 작용하는 GABA계 부위의 세가지 방법으로 억제성인 교감신경기능을 불활성화하여 일어나는 것으로 추론하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제11권3호
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• pp.97-106
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• 2007

The present study was attempted to investigate the effect of nicorandil, which is an ATP-sensitive potassium ($K_{ATP}$) channel opener, on secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from the isolated perfused rat adrenal glands. The perfusion of nicorandil ($0.3{\sim}3.0mM$) into an adrenal vein for 90 min produced relatively dose-and time-dependent inhibition in CA secretion evoked by ACh (5.32 mM), high $k^+$ (a direct membrane depolarizer, 56 mM), DMPP (a selective neuronal nicotinic receptor agonist, $100{\mu}M$ for 2 min), McN-A-343 (a selective muscarinic $M_1$ receptor agonist, $100{\mu}M$ for 4 min), Bay-K-8644 (an activator of L-type dihydropyridine $Ca^{2+}$ channels, $10{\mu}M$ for 4 min) and cyclopiazonic acid (an activator of cytoplasmic $Ca^{2+}$-ATPase, $10{\mu}M$ for 4 min). In adrenal glands simultaneously preloaded with nicorandil (1.0 mM) and glibenclamide (a nonspecific $K_{ATP}$-channel blocker, 1.0 mM), the CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were recovered to the considerable extent of the control release in comparison with that of nicorandil-treatment only. Taken together, the present study demonstrates that nicorandil inhibits the adrenal CA secretion in response to stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization from the isolated perfused rat adrenal glands. It seems that this inhibitory effect of nicorandil may be mediated by inhibiting both $Ca^{2+}$ influx and the $Ca^{2+}$ release from intracellular store through activation of $K_{ATP}$ channels in the rat adrenomedullary chromaffin cells. These results suggest that nicorandil-sensitive $K_{ATP}$ channels may play an inhibitory role in the regulation of the rat adrenomedullary CA secretion.

• The Korean Journal of Physiology and Pharmacology
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• 제18권4호
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• pp.313-320
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• 2014

The study was conducted to investigate the role of vitamin E in the high altitude hypoxia-induced damage to the intestinal barrier in rats. Sprague-Dawley rats were divided into control (Control), high altitude hypoxia (HH), and high altitude hypoxia + vitamin E (250 mg/kg $BW^*d$) (HV) groups. After the third day, the HH and HV groups were placed in a hypobaric chamber at a stimulated elevation of 7000 m for 5 days. The rats in the HV group were given vitamin E by gavage daily for 8 days. The other rats were given equal volume saline. The results showed that high altitude hypoxia caused the enlargement of heart, liver, lung and kidney, and intestinal villi damage. Supplementation with vitamin E significantly alleviated hypoxia-caused damage to the main organs including intestine, increased the serum superoxide dismutase (SOD) (p< 0.05), diamino oxidase (DAO) (p< 0.01) levels, and decreased the serum levels of interleukin-2 (IL-2) (p< 0.01), interleukin-4 (IL-4) (p<0.001), interferon-gamma ($IFN-{\gamma}$) (p<0.01) and malondialdehyde (MDA) (p<0.001), and decreased the serum erythropoietin (EPO) activity (p<0.05). Administration of vitamin E significantly increased the S-IgA (p<0.001) in ileum and significantly improved the expression levels of occludin and $I{\kappa}B{\alpha}$, and decreased the expression levels of hypoxia-inducible factor 1 alpha and 2 alpha ($HIF-1{\alpha}$ and $HIF-2{\alpha}$), Toll-like receptors (TLR4), P-$I{\kappa}B{\alpha}$ and nuclear factor-${\kappa}B$ p65(NF-${\kappa}B$ P65) in ileum compared to the HH group. This study suggested that vitamin E protectis from intestinal injury caused by high altitude hypoxia environment. These effects may be related to the HIF and TLR4/NF-${\kappa}B$ signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.223-228
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• 2013

The calcium-activated $K^+$ ($BK_{Ca}$) channel is one of the potassium-selective ion channels that are present in the nervous and vascular systems. $Ca^{2+}$ is the main regulator of $BK_{Ca}$ channel activation. The $BK_{Ca}$ channel contains two high affinity $Ca^{2+}$ binding sites, namely, regulators of $K^+$ conductance, RCK1 and the $Ca^{2+}$ bowl. Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is one of the neurolipids. LPA affects diverse cellular functions on many cell types through G protein-coupled LPA receptor subtypes. The activation of LPA receptors induces transient elevation of intracellular $Ca^{2+}$ levels through diverse G proteins such as $G{\alpha}_{q/11}$, $G{\alpha}_i$, $G{\alpha}_{12/13}$, and $G{\alpha}s$ and the related signal transduction pathway. In the present study, we examined LPA effects on $BK_{Ca}$ channel activity expressed in Xenopus oocytes, which are known to endogenously express the LPA receptor. Treatment with LPA induced a large outward current in a reversible and concentration-dependent manner. However, repeated treatment with LPA induced a rapid desensitization, and the LPA receptor antagonist Ki16425 blocked LPA action. LPA-mediated $BK_{Ca}$ channel activation was also attenuated by the PLC inhibitor U-73122, $IP_3$ inhibitor 2-APB, $Ca^{2+}$ chelator BAPTA, or PKC inhibitor calphostin. In addition, mutations in RCK1 and RCK2 also attenuated LPA-mediated $BK_{Ca}$ channel activation. The present study indicates that LPA-mediated activation of the $BK_{Ca}$ channel is achieved through the PLC, $IP_3$, $Ca^{2+}$, and PKC pathway and that LPA-mediated activation of the $BK_{Ca}$ channel could be one of the biological effects of LPA in the nervous and vascular systems.

• Restorative Dentistry and Endodontics
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• 제32권6호
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• pp.514-521
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• 2007

[ $P2X_3$ ] 수용기는 세포 외에 존재하는 ATP에 의하여 활성화되는 ligand-gated cation channel로서 염증 혹은 조직 손상 시 세포에서 유리된 ATP가 $P2X_3$ 수용기와 결합하여 동통을 유발하는 것으로 알려져 있다. 이에 본 연구는 형광면역조직화학기법을 통하여 사람의 치수에서 $P2X_3$의 발현과 바닐로이드 수용기인 TRPV1과의 공존 양상을 확인함으로써 이들의 치수동통전달 기전을 밝히고자 시행되었다. 사람의 치수에서는 치관부 및 치근부 전체에 걸쳐 다수의 $P2X_3$ 면역양성 신경섬유가 관찰되었으며 이 중 약 79.4%에서 TRPV1과의 공존을 보였다. 이상의 결과로 사람의 치수에서 $P2X_3$는 TRPV1과 더불어 치수염증 시 중추로의 동통전달과 유해자극의 증폭에 있어서 중요한 역할을 할 것으로 사료된다.