• Animal cells and systems
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• 제7권2호
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• pp.151-157
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• 2003

Calretinin is thought to play roles in calcium buttering. Its site of expression has been extensively studied in the central nervous system. We previously reported (Hong et at.,2002, Neurosci. Res.,44: 325-335) calretinin expression in the superficial layers of the cat superior colliculus (SC). In the present study, we studied the distribution of calretinin in the intermediate and deep layers by immunocytochemistry. We found striking differences in calretinin immunoreactivity among the superficial, intermediate, and deep layers. In contrast to the superficial layers, the intermediate and deep layers contained many calretinin-immunoreactive (IR) neurons. They formed two laminar tiers. The first tier, which was very distinctive, was found within the upper intermediate gray layers and formed clusters of labeled neurons in many sections. The second tier of calretinin-IR neurons was found in the deep gray layer. However, the second tier was not distinctive compared to the first tier and the labeled neurons did not form any clusters. Calretinin-IR neurons in the intermediate and deep layers varied dramatically in morphology and included vortical fusiform, pyriform, and stellate neurons. Neurons with varicose dendrites were also labeled. Most of the labeled neurons were small to medium in size. Enucleation appeared to have no effect on the distribution of calretinin immunoreactivity in the contralateral intermediate and deep layers of the SC. The results indicate that calretinin is present in various neurons, at different locations. These results should be applicable for better understanding of the functional organization of the SC.

• Applied Microscopy
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• 제40권1호
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• pp.15-19
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• 2010

이번 연구에서는 성체 랫드(Sprague-Dawley)의 척수신경절내 분포하는 zinc의 분포 관찰하기 위하여 zinc selenium autometallograpy(AMG)로 염색하였다. H-E염색표본에서 척수신경절 속에는 신경절세포들이 무리지어 분포하고 있었고, 세포체는 둥글거나 타원형이었으며, 작은 신경절세포, 큰 신경절세포로 대별되었다. 모든 신경절세포의 세포체는 한 층의 납작한 위성세포(satellite cell)에 의하여 둘러싸여 있었다. AMG 염색표본에서는 작은 신경절세포의 경우 강한 양성반응이 핵 주변부에서 관찰되었으나, 큰 신경절세포의 경우 전반적으로 미약한 AMG 양성반응을 보였고, 염색양상도 서로 달랐다. 그러나 큰 신경절세포를 둘러싸는 위성세포에서는 뚜렷한 AMG 양성반응이 관찰되었다. 이러한 조직화학적 본 연구의 결과는 zinc가 감각신경절인 랫드 척수신경절에서 통증을 포함한 감각의 전달과정에 의미있는 기능을 영위할 수 있음을 시사한다.

• Toxicological Research
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• 제12권2호
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• pp.203-211
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• 1996

Methanol has been widely used as an industrial solvent and environmental exposure to methanol would be expected to be increasing. In humans, methanol causes metabolic acidosis and damage to ocular system, and can lead to death in severe and untreated case. Clinical symptoms are attributed to accumulation of forrnic acid which is a metabolic product of methanol. In humans and primates, formic acid is accumulated after methanol intake but not in rodents due to the rapid metabolism of methanol. Neverthless, the developmental and reproductive toxicity were reported in rodents. Previous reports showed that perinatal exposure to ethanol produces a variety of damage in human central nervous system by direct neurotoxicity. This suggests that the mechanism of toxic symptoms by methanol in rodents might mimic that of ethanol in human. In the present study I hypothesized that methanol can also induce toxicity in neuronal cells. For the study, primary culture of rat hippocampal neurons and glias were empolyed. Hippocampal cells were prepared from the embryonic day-17 fetuses and maintained up to 7 days. Effect of methanol (10, 100, 500 and 1000 mM) on neurite outgrowth and cell viability was investigated at 0, 18 and 24 hours following methanol treatment. To study the changes in proliferation of glial cells, protein content was measured at 7 days. Neuronal cell viability in culture was not altered during 0-24 hours after methanol treatment. 10 and 100 mM methanol treatment significantly enhanced neurite outgrowth between 18-24 hours. 7-day exposure to 10 or 100 mM methanol significantly increased protein contents but that to 1000 mM methanol decreased in culture. In conclusion, methanol may have a variety of effects on growing and differentiation of neurons and glial cells in hippocampus. Treatment with low concentration of methanol caused that neurite outgrowth was enhanced during 18-24 hours and the numbers of glial cell were increased for 7 days. High concentration of methanol brought about decreased protein contents. At present, the mechanism responsible for the methanol- induced enhancement of neurite outgrowth is not clear. Further studies are required to delineate the mechanism possibly by employing molecular biological techniques.

• Korean Journal of Acupuncture
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• 제38권1호
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• pp.32-42
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• 2021

Objectives : In this study, we investigated the neuroprotective effects of ethanol extract of Lonicera japonica flower buds (EELJ) on glutamate-induced neurotoxicity in mouse hippocampus-derived neuronal HT22 cells. Methods : After analyzing the cytoprotective effect of EELJ on glutamate in HT22 cells, the inhibitory effect of apoptosis was studied using flow cytometry. In order to analyze the antioxidant efficacy of EELJ, the levels of reactive oxygen species (ROS) and glutathione (GSH) were investigated, and the effects on the activities of superoxide dismutase (SOD) and catalase (CAT) were also analyzed. Furthermore, the effect of EELJ on the expression of apoptosis regulators such as Bax and Bcl-2 in glutamate-treated HT22 cells was investigated. Results : According the current results, pretreatment with EELJ significantly reduced glutamate-induced loss of cell viability and release of lactate dehydrogenase. EELJ also markedly attenuated glutamate-induced generation of intracellular ROS, which was associated with increased levels of GSH, and activity of SOD and CAT in glutamate-stimulated HT22 cells. In addition, EELJ was strikingly inhibited glutamate-induced apoptosis in HT22 cells. Furthermore, the expression of pro-apoptotic Bax was increased and the expression of anti-apoptotic Bcl-2 was decreased in glutamate-treated HT22 cells, while in the presence of EELJ, their expressions were maintained at the control levels. Conclusions : These findings indicate that EELJ protects glutamate-induced cytotoxicity in HT22 hippocampal neurons through antioxidant activity. Therefore, although identification of biologically active substances of EELJ and re-evaluation through animal experiments is necessary, this natural substance is a promising candidate for further research in preventing and treating oxidative stress-mediated neurodegenerative diseases.

• 대한의생명과학회지
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• 제16권1호
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• pp.46-52
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• 2010

This study was designed to investigate the effects of sphingosine-1-phosphate on the neuronal activity of rat medial vestibular nuclear neurons. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated medial vestibular nuclear neurons were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium currents were recorded by standard patch-clamp techniques under current and voltage-clamp modes respectively. 15 medial vestibular nuclear neurons revealed excitatory responses to 1 and $5\;{\mu}M$ of sphingosine-1-phosphate. The spike frequency and resting membrane potential of these cells were increased by sphingosine-1-phosphate. The amplitude of afterhyperpolarization was decreased by sphingosine-1-phosphate. Whole potassium currents of medial vestibular nuclear neurons were decreased by sphingosine-1-phosphate (n=12). Sphingosine-1-phosphate did not affect the charybdotoxin-treated potassium currents. These experimental results suggest that sphingosine-1-phosphate increases the neuronal activity of the medial vestibular nuclear neurons by altering the resting membrane potential and afterhyperpolarization.

• The Korean Journal of Physiology and Pharmacology
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• 제2권3호
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• pp.297-305
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• 1998

This study used in vivo intracellular recording in rat hippocampus to evaluate the effect of lidocaine and MK-801 on the membrane properties and the synaptic responses of individual neurons to electrical stimulation of the commissural pathway. Cells in control group typically fired in a tonic discharge mode with an average firing frequency of $2.4{\pm}0.9$ Hz. Neuron in MK-801 treated group (0.2 mg/kg, i.p.) had an average input resistance of $3.28{\pm}5.7\;M{\Omega}$ and a membrane time constant of $7.4{\pm}1.8$ ms. These neurons exhibited $2.4{\pm}0.2$ ms spike durations, which were similar to the average spike duration recorded in the neurons of the control group. Slightly less than half of these neurons were firing spontaneously with an average discharge rate of $2.4{\pm}1.1$ Hz. The average peak amplitude of the AHP following the spikes in these groups was $7.4{\pm}0.6$ mV with respect to the resting membrane potential. Cells in MK-801 and lidocaine treated group (5 mg/kg, i.c.v.) had an average input resistance of $3.45{\pm}6.0\;M{\Omega}$ and an average time constant of $8.0{\pm}1.4$ ms. The cells were firing spontaneously at an average discharge rate of $0.6{\pm}0.4$ Hz. Upon depolarization of the membrane by 0.8 nA for 400 ms, all of the tested cells exhibited accommodation of spike discharge. The most common synaptic response contained an EPSP followed by early-IPSP and late-IPSP. Analysis of the voltage dependence revealed that the early-IPSP and late-IPSP were putative $Cl^--and\;K^+-dependent$, respectively. Systemic injection of the NMDA receptor blocker, MK-801, did not block synaptic responses to the stimulation of the commissural pathway. No significant modifications of EPSP, early-IPSP, or late-IPSP components were detected in the MK-801 and/or lidocaine treated group. These results suggest that MK-801 and lidocaine manifest their CNS effects through firing pattern of hippocampal pyramidal cells and neural network pattern by changing the synaptic efficacy and cellular membrane properties.

• Reproductive and Developmental Biology
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• 제28권4호
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• pp.247-252
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• 2004

Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.

• 동의생리병리학회지
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• 제17권2호
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• pp.447-450
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• 2003

To clerify the cytotoxicity of reactive oxygen species in cultured hippocampal neurons of neonatal mouse, toxic effect was measured by MTT assay after cultured cells were incubated for 3 hours in the media containing 1～40 μM concentrations of H₂O₂. In addition, the protective effect of vitamin E was determined in these cultrures. Cell viability was significantly decreased in a dose-dependent manner after exposure of 10 μM H₂O₂ to cultured mouse hippocampal neurons for 5 hours. In the protective effect of vitamin E, vitamin E prevented the H₂O₂-induced cytotoxicity in these cultures. From these results, it suggests that H₂O₂ has toxic effect in cultured mouse hippocampal neurons and vitamin E has protective effect on the cytotoxicity induced by H₂O₂.

• Molecules and Cells
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• 제39권12호
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• pp.841-846
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• 2016

Local protein synthesis mediates precise spatio-temporal regulation of gene expression for neuronal functions such as long-term plasticity, axon guidance and regeneration. To reveal the underlying mechanisms of local translation, it is crucial to understand mRNA transport, localization and translation in live neurons. Among various techniques for mRNA analysis, fluorescence microscopy has been widely used as the most direct method to study localization of mRNA. Live-cell imaging of single RNA molecules is particularly advantageous to dissect the highly heterogeneous and dynamic nature of messenger ribonucleoprotein (mRNP) complexes in neurons. Here, we review recent advances in the study of mRNA localization and translation in live neurons using novel techniques for single-RNA imaging.

• 대한의생명과학회지
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• 제15권1호
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• pp.97-99
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• 2009

Geldanamycin is a benzoquinone ansamycin antibiotic that binds to cytosol HSP90 (Heat Shock Protein 90) and changes its biological function. HSP90 is involved in the intracellular important roles for the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. To identify genes expressed during geldanamycin treatment against neurons of rats (PC12 cells), DNA microarray method was used. We have isolated 2 gene groups (up-or down-regulated genes) which are geldanamycin differentially expressed in neurons. Granzyme B is the gene most significantly increased among 204 up-regulated genes (more than 2 fold over-expression) and Chemokine (C-C motif) ligand 20 is the gene most dramatically decreased among 491 down-regulated genes (more than 2 fold down-expression). The gene increased expression of Cxc110, Cyp11a1, Gadd45a, Gja1, Gpx2, Ifua4, Inpp5e, Sox4, and Stip1 are involved stress-response gene, and Cryab, Dnaja1, Hspa1a, Hspa8, Hspca, Hspcb, Hspd1, Hspd1, and Hsph1 are strongly associated with protein folding. Cell cycle associated genes (Bc13, Brca2, Ccnf, Cdk2, Ddit3, Dusp6, E2f1, Illa, and Junb) and inflammatory response associated genes (Cc12, Cc120, Cxc12, Il23a, Nos2, Nppb, Tgfb1, Tlr2, and Tnt) are down-regulated more than 2 times by geldanamycin treatment. We found that geldanamycin is related to expression of many genes associated with stress response, protein folding, cell cycle, and inflammation by DNA microarray analysis. Further experimental molecular studies will be needed to figure out the exact biological function of various genes described above and the physiological change of neuronal cells by geldanamycin. The resulting data will give the one of the good clues for understanding of geldanamycin under molecular level in the neurons.