• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 춘계학술대회
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• pp.107-107
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• 2003

The heavy metal cadmium is a xenobiotic toxicant of environmental and occupational concern and it has been classified as a human carcinogen. Inhalation of cadmium has been implicated in the development of emphysema and pulmonary fibrosis, but, the detailed mechanism by which cadmium induces adverse biological effects is not yet known. Therefore, we undertook the investigation of genes that are induced after cadmium exposure to illustrate the mechanism of cadmium toxicity For this purpose, we employed the polymerase chain reaction-based suppression subtractive hybridization technique. We identified 29 different cadmium-inducible genes in human peripheral mononuclear cells, such as macrophage migration inhibitory factor, lysophosphatidic acid acyltransferase-${\alpha}$, enolase-1${\alpha}$, VEGF, Bax, neuron-derived orphan receptor-1, and Nur77, which are known to be associated with inflammation, cell survival, and apoptosis. Induction of these genes by cadmium treatment was further confirmed by semi-quantitative reverse-transcription polymerase chain reaction. Further, we found that these genes were also induced after cadmium exposure in normal human lung fibroblast cell line, WI-38, suggesting potential use of this induction profile to monitor cadmium toxicity in the lung. Next, Nur77, one of cadmium-inducible genes, was further studied since the products of Nur77 are known to be involved in the apoptotic process of lung cells. Following cadmium treatment, Nur77 gene expression was increased at protein-level in A549 cells. Consistently, the reporter containing Nur77 binding sequence was activated by 2.5-fold after exposure to cadmium in reporter gene analysis by transient transfection experiments. When the plasmid encoding dominant negative Nur77 that represses the transcriptional function of wild-type Nur77 was transfected into A549 cells, the expression of Bax was significantly reduced, suggesting that induction of Nur77 was an important process in cadmium-induced apoptosis in the cells. Cadmium induced the expression of Nur77 in vivo, confirming the relevance of the data obtained in viro. Together our results suggest that Nur77 gene expression in exposure to cadmium leads apoptosis of lung cells which may cause pathological changes in lung.

• The Korean Journal of Physiology and Pharmacology
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• 제5권2호
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• pp.189-197
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• 2001

To investigate propofol's effects on ionic currents induced by ${\gamma}-aminobutyric$ acid (GABA) and glycine as well as on those produced by the nicotinic acetylcholine- and glutamate-responsive channels, rat dorsal raphe neurons were acutely dissociated and the nystatin-perforated patch-clamp technique under voltage-clamp conditions was used to observe their responses to the administration of propofol. Propofol evoked ion currents in a dose-dependent manner, and propofol $(10^{-4}\;M)$ was used to elicit ion currents through the activation of $GABA_A,$ glycine, nicotinic acetylcholine and glutamate receptors. Propofol at a clinically relevant concentration $(10^{-5}\;M)$ potentiated $GABA_A-,$ glycine- and NMDA receptor-mediated currents. The potentiating action of propofol on $GABA_A-,$ glycine- and NMDA receptor-mediated responses involved neither opioid receptors nor G-proteins. Apparently, propofol modulates inhibitory and excitatory neurotransmitter-activated ion channels either by acting directly on the receptors or by potentiating the effects of the neurotransmitters, and this modulation appears to be responsible for the majority of the anaesthetic and/or adverse effects.

• The Korean Journal of Physiology and Pharmacology
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• 제10권3호
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• pp.131-135
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• 2006

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that ${\alpha}-receptor$ mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

• 대한한의학회지
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• 제25권3호
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• pp.32-44
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• 2004

Objectives : This study was undertaken to prove the effect of GSHT on the glutamate receptor, free radical and brain damage in rats subjected to brain ischemia Methods : Levels of cultured cortical neuron death caused by toxic chemicals were measured by LDH release assay. Neuroprotective effects of GSHT on brain tissues were examined in vivo by ischemic model of middle cerebral artery (MCA) occlusion. Results : GSHT showed significant inhibitory effect on LDH release induced by NMDA-kinate-Fe/sup 2+/. GSHT remarkably decreased coma duration time in a nonfatal dose of KCN and showed higher survival rate in a fatal dose. GSHT remarkably decreased ischemic area and edema induced by the MCA blood flow block. GSHT showed high improvement of forelimb and hind limb test after MCA occlusion in neurological examination. GSHT showed no significant change after MCA occlusion in pathological observation of the normal group. Conclusions : These results indicate that GSHT can be used to treat the brain damage caused by brain ischemia. Further study will be needed about the functional mechanism, etc.

• Archives of Pharmacal Research
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• 제27권5호
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• pp.524-530
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• 2004

Epilepsy or the occurrence of spontaneous recurrent epileptiform discharges (SREDs, seizures) is one of the most common neurological disorders. Shift in the balance of brain between excitatory and inhibitory functions due to different types of structural or functional alterations may cause epileptiform discharges. N-Methyl-D-aspartate (NMDA) receptor dysfunctions have been implicated in modulating seizure activities. Seizures and epilepsy are clearly dependent on elevated intracellular calcium concentration ([C $a^{2+}$]$_{i}$ ) by NMDA receptor activation and can be prevented by NMDA antagonists. This perturbed [C $a^{2+}$]$_{i}$ levels is forerunner of neuronal death. However, therapeutic tools of elevated [C $a^{2+}$]$_{i}$ level during status epilepticus (SE) and SREDs have not been discovered yet. Our previous study showed fast inhibition of ginseng total saponins and ginsenoside R $g_3$ on NMDA receptor-mediated [C $a^{2+}$]$_{i}$ in cultured hippocampal neurons. We, therefore, examined the direct modulation of ginseng on hippocampal neuronal culture model of epilepsy using fura-2-based digital $Ca^{2+}$ imaging and neuronal viability assays. We found that ginseng total saponins and ginsenoside R $g_3$ inhibited $Mg^{2+}$ free-induced increase of [C $a^{2+}$]$_{i}$ and spontaneous [C $a^{2+}$]$_{i}$ oscillations in cultured rat hippocampal neurons. These results suggest that ginseng may playa neuroprotective role in perturbed homeostasis of [C $a^{2+}$]$_{i}$ and neuronal cell death via the inhibition of NMDA receptor-induced SE or SREDs.d SE or SREDs..

• 생명과학회지
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• 제19권8호
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• pp.1062-1066
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• 2009

N-Acetylglucosamine kinase (GlcNAc kinase or NAGK; EC 2.7.1.59)는 GlcNAc를 인산화하여 GlcNAc-6-phosphate를 만드는 효소이다. 효소자체에 대한 자세한 연구에도 불구하고 포유류에서NAGK의 표현에 대한 연구는 거의 없다. 배양한 흰쥐의 해마신경세포에서 NAGK은 세포체/가지돌기 영역에서 클러스터(cluster)를 형성한다. 본 연구에서는 가지돌기의 긴 축에서부터 가쪽으로 돌출되는 NAGK 클러스터에 대하여 연구하였다. 배양한 해마신경세포를 NAGK와 다양한 연접표지단백질에 대한 항체로 이중염색한 결과 NAGK 클러스터가 가지돌기의 바닥에는 있었지만 억제성 연접후부위에는 존재하지 않았다. 또한 흰쥐 전뇌(forebrain)의 균질액(homogenate, BH), 연접체(synaptosome, S), 연접후치밀질(postsynaptic density, PSD) 분획을 NAGK 항체로 면역염색한 결과 NAGK는 연접체에는 있었지만 PSD 분획에는 존재하지 않았다. 이러한 결과들은 NAGK가 가지돌기가시(spine)의 바닥쪽으로 돌출됨을 의미한다.

• The Korean Journal of Physiology and Pharmacology
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• 제5권3호
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• pp.213-221
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• 2001

The amygdala is known as a site for inducing analgesia, but its action on the trigeminal nucleus has not been known well. Little information is available on the effect of dynorphin on NMDA receptor-mediated electrophysiological events in the trigeminal nucleus. The purpose of this study was to investigate the changes in the single neuron spikes at the trigeminal nucleus caused by the amygdala and the action of dynorphin on the trigeminal nucleus. In the present study, extracellular single unit recordings were made in the dorsal horn of the medulla (trigeminal nucleus caudalis) and the effects of microiontophoretically applied compounds were examined. When [D-Ala2, N-Me-Phe4, Glys5-ol]enkephalin (DAMGO, 10-25 mM), a ${\mu}-opioid$ receptor agonist, was infused into the amygdala, the number of NMDA-evoked spikes at the trigeminal nucleus decreased. However, the application of naloxone into the trigeminal nucleus while DAMGO being infused into the amygdala increased the number of spikes. Low dose (1 mM) of dynorphin in the trigeminal nucleus produced a significant decrease in NMDA-evoked spikes of the trigeminal nucleus but the NMDA-evoked responses were facilitated by a high dose (5 mM) of dynorphin. After the ${\kappa}$ receptors were blocked with naloxone, dynorphin induced hyperalgesia. After the NMDA receptors were blocked with AP5, dynorphin induced analgesia. In conclusion, dynorphin A exerted dose-dependent dual effects (increased & decreased spike activity) on NMDA-evoked spikes in the trigeminal nucleus. The inhibitory effect of the dynorphin at a low concentration was due to the activation of ${\kappa}$ receptors and the excitatory effect at a high concentration was due to activation of NMDA receptors in the trigeminal neurons.

• 통합자연과학논문집
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• 제7권1호
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• pp.25-38
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• 2014

Amyloid-${\beta}$-peptide ($A{\beta}$) is important in the pathogenesis of Alzheimer's disease (AD). Calpain ($Ca^{2+}$-dependent protease) and caspase-8 (the initiating caspase for the extrinsic, receptor-mediated apoptosis pathway) have been implicated in $AD/A{\beta}$ toxicity. We found that $A{\beta}$ promoted degradation of calpastatin (the specific endogenous calpain inhibitor); calpastatin degradation was prevented by inhibitors of either calpain or caspase-8. The results implied a cross-talk between the two proteases and suggested that one protease was responsible for the activity of the other one. In neuron-like differentiated PC12 cells, calpain promotes active caspase-8 formation from procaspase-8 via the $A{\beta}$ and CD95 pathways, along with degradation of the procaspase-8 processing inhibitor caspase-8 (FLICE)-like inhibitory protein, short isoform (FLIPS). Inhibition of calpain (by pharmacological inhibitors and by overexpression of calpastatin) prevents the cleavage of procaspase-8 to mature, active caspase-8, and inhibits FLIPS degradation in the $A{\beta}$-treated and CD95-triggered cells. Increased cellular Ca2+ per se results in calpain activation but does not lead to caspase-8 activation or FLIPS degradation. The results suggest that procaspase-8 and FLIPS association with cell membrane receptor complexes is required for calpain-induced caspase-8 activation. The results presented here add to the understanding of the roles of calpain, caspase- 8, and CD95 pathway in $AD/A{\beta}$ toxicity. Calpain-promoted activation of caspase-8 may have implications for other types of CD95-induced cell damage, and for nonapoptotic functions of caspase-8. Inhibition of calpain may be useful for modulating certain caspase-8-dependent processes.

• 한국식품과학회지
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• 제48권3호
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• pp.284-288
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• 2016

본 연구에서는 고포도당 조건에서 로젤의 산화방지 효과와 산화 손상에 대한 신경세포 보호효과를 검증하였다. 총 페놀 함량은 아세트산에틸 분획물(71.41 mg GAE/g)이 다른 분획물보다 높았으며, 이에 따라 아세트산에틸 분획물로 in vitro 산화방지 실험을 진행한 결과 상대적으로 우수한 ABTS 라디칼 소거활성과 지방질과산화물 생성 억제효과를 나타내었다. 신경세포에 고포도당으로 유발시킨 산화 스트레스에 대한 로젤 아세트산에틸 분획물은 산화 스트레스의 생성을 억제하고 신경세포 생존율을 향상 시켰다. 더불어 신경전달물질인 아세틸콜린 분해하는 아세틸콜린 에스터레이스의 억제효과를 보였으며, 마지막으로 HPLC 분석 결과 로젤 아세트산에틸 분획물에 존재하는 주요 페놀화합물은 클로로겐산인 것으로 판단되었다. 결국 클로로겐산을 함유하는 로젤 아세트산에틸 분획물은 우수한 산화방지 효과와 신경세포 보호효과 그리고 아세틸콜린 에스터레이스 억제 효과를 유도한 것으로 추정되며, 이를 통해 고포도당 상태에서 발생하는 당뇨성 퇴행성 신경질환과 같은 질병을 예방할 수 있는 고부가가치 소재로서의 활용가치가 있다고 판단된다.

• 동의생리병리학회지
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• 제17권2호
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• pp.529-541
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• 2003

Yukmijihwang-tang has been widely used as an and-aging herbal medicine for hundred years in Asian countries. Numerous studies show that Yukmijihwangtang has anti-oxidative effect both in vivo and in vitro. It has been reported that Moutan Cortex Radicis extract (MCR) was the most effective herb in Yukmijihwang-tang on undifferentiated PC12 cells upon oxidative-stressed with hydrogen peroxide. The purpose of this study is to; 1) evaluate the recovery of neuronal damage by assessing the anti-oxidant effect of MCR on PC12 cells differentiated with nerve growth factor (NGF), 2) identify candidate genes responsible for anti-oxidative effect on differentiated PC12 cells by oligonucleotide chip microarray. PC12 cells, which were differentiated by treating with NGF, were treated without or with hydrogen peroxide in the presence or absence of various concentration of MCR. Cell survival was determined by using MTS assay. Measurement of intracellular reactive oxygen species (ROS) generation was determined using the H2DCFDA assay The viability of cells treated with MCR was significantly recovered from stressed PC12 cell. In addition, wide rage of concentrations of MCR shows dose-dependent inhibitory effect on ROS production in oxidative-stressed cells. Total RNAs of cells without treatment(Control group), only treated with H₂O₂ (stressed group) and treated with both H₂O₂ and of MCR (MCR group) were isolated, and cDNAs was synthesized using oligoT7(dT) primer. The fragmented cRNAs, synthesized from cDNAs, were applied to Affymetrix GeneChip Rat Neurobiology U34 Array. mRNA of Calcium/calmodulin-dependent protein kinase II delta subunit(CaMKII), neuron glucose transporter (GLUT3) and myelin/oligodendrocyte glycoprotein(MOG) were downregulated in Stressed group comparing to Control group. P2X2-5 receptor (P2X2R-5), P2X2-4 receptor (P2X2R-4), c-fos, 25 kDa synaptosomal attachment protein(SNAP-25a) and GLUT3 were downregulated, whereas A2 adenosine receptor (A2AR), cathechol-O-methyltransferase(COMT), glucose transporter 1 (GLUT1), EST223333, heme oxygenase (HO), VGF, UI-R-CO-ja-a-07-0-Ul.s1 and macrophage migration inhibitory factor (MIF) were upregulated in MCA group comparing to Control group. Expression of Putative potassium channel subunit protein (ACK4), P2X2A-5, P2X2A-4, Interferon-gamma inducing factor isoform alpha precursor (IL-18α), EST199031, P2XR, P2X2 purinoceptor isoform e (P2X2R-e), Precursor interleukin 18 (IL-18) were downregulated, whereas MOO, EST223333, GLUT-1, MIF, Neuronatin alpha, UI-R-C0-ja-a-07-0-Ul.s1, A2. adenosine receptor, COMT, neuron-specific enolase (NSE), HO, VGF, A rat novel protein which is expressed with nerve injury (E12625) were upregulated in MCR group comparing to Stressed group. The results suggest that decreased viability and AOS production of PC12 cell by H₂O₂ may be, at lease, mediated by impaired glucose transporter expression. It is implicated that the MCR treatment protect PC12 cell from oxidative stress via following mechanisms; improving glucose transport into the cell, enhancing expression of anti-oxidative genes and protecting from dopamine cytotoxicity by increment of COMT and MIF expression. The list of differentially expressed genes may implicate further insight on the action and mechanism behind the anti-oxidative effects of herbal extract Moutan Cortex Radicis.