• The Korean Journal of Physiology and Pharmacology
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• v.13 no.4
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• pp.265-271
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• 2009

Nitric oxide (NO) has both neuroprotective and neurotoxic effects depending on its concentration and the experimental model. We tested the effects of NG-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a selective inducible NOS (iNOS) inhibitor, on kainic acid (KA)-induced seizures and hippocampal CA3 neuronal death. L-NAME (50 mg/kg, i.p.) and/or aminoguanidine (200 mg/kg, i.p.) were administered 1 h prior to the intracerebroventricular (i.c.v.) injection of KA. Pretreatment with L-NAME significantly increased KA-induced CA3 neuronal death, iNOS expression, and activation of microglia. However, pretreatment with aminoguanidine significantly suppressed both the KA-induced and L-NAME-aggravated hippocampal CA3 neuronal death with concomitant decreases in iNOS expression and microglial activation. The protective effect of aminoguanidine was maintained for up to 2 weeks. Furthermore, iNOS knockout mice ($iNOS^{-1-}$) were resistant to KA-induced neuronal death. The present study demonstrates that aminoguanidine attenuates KA-induced neuronal death, whereas L-NAME aggravates neuronal death, in the CA3 region of the hippocampus, suggesting that NOS isoforms play different roles in KA-induced excitotoxicity.

• Journal of electromagnetic engineering and science
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• v.15 no.3
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• pp.173-180
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• 2015

To explore the effects of radiofrequency electromagnetic field on the fate of neuronal cells, we investigated whether exposure to 915 MHz radiofrequency identification (RFID) caused morphological changes in neuronal cells in rat hippocampal dentate gyrus (DG). A reverberation chamber was used as a whole-body RFID exposure system. Rats were assigned to two groups: sham- and RFID-exposed groups. Rats in the RFID-exposed group were exposed to RFID at 4 W/kg specific absorption rate (SAR) for 8 hours daily, 5 days per week, for 2 weeks. Morphological evaluation of DG was performed using immunohistochemistry with doublecortin (DCX) as a neuronal precursor cell marker and neuronal nuclei (NeuN) as a mature neuronal cell marker. No significant morphological changes in DCX+ or NeuN+ cells in the DG of RFID-exposed rats were observed. These results suggest that RFID exposure induces no significant change in DCX+ neuronal precursor or NeuN+ neuronal cells in DG of rats.

• YAKHAK HOEJI
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• v.55 no.5
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• pp.385-390
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• 2011

Bee venom (BV), which is extracted from honeybees, has been used in traditional Korean medical therapy. Glutamate-mediated excitotoxicity contributes to neuronal death in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) or Alzheimer's disease (AD). This study is to investigate the effect of BV on glutamate-induced neurotoxicity on NSC-34 motor neuron cells. To determine the viability of motor neuronal cells, we performed with MTT assays in glutamate-treated NSC-34 cell with BV or without. For the measurement of oxidative stress, DCF assay was used in glutamate-treated NSC-34 motor neuronal cells with BV or without. To investigate the molecular mechanism of BV against glutamate-mediated neurotoxicity in NSC-34 cells, western blot analysis was used. Glutamate significantly decreased cell viability by glutamate dose- or treatment time-dependent manner in NSC-34 cells. However, BV pre-treatment dramatically inhibited glutamate-induced neuronal cell death. Furthermore, we found that BV increased the expression of Bcl-2 protein that is anti-apoptotic protein and reduced the generation of oxidative stress. BV has a neuroprotective role against glutamate neurotoxicity by an increase of anti-apoptotic protein. It suggests that BV may be useful for the reduction of neuronal cell death in neuronal disease models.

• BMB Reports
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• v.49 no.12
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• pp.671-680
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• 2016

Accumulating evidence indicates many brain functions are mediated by epigenetic regulation of neural genes, and their dysregulations result in neuronal disorders. Experiences such as learning and recall, as well as physical exercise, induce neuronal activation through epigenetic modifications and by changing the noncoding RNA profiles. Animal models, brain samples from patients, and the development of diverse analytical methods have broadened our understanding of epigenetic regulation in the brain. Diverse and specific epigenetic changes are suggested to correlate with neuronal development, learning and memory, aging and age-related neuronal diseases. Although the results show some discrepancies, a careful comparison of the data (including methods, regions and conditions examined) would clarify the problems confronted in understanding epigenetic regulation in the brain.

• BMB Reports
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• v.48 no.4
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• pp.229-233
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• 2015

The central nervous system (CNS) controls food intake and energy expenditure via tight coordinations between multiple neuronal populations. Specifically, two distinct neuronal populations exist in the arcuate nucleus of hypothalamus (ARH): the anorexigenic (appetite-suppressing) pro-opiomelanocortin (POMC) neurons and the orexigenic (appetite-increasing) neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The coordinated regulation of neuronal circuit involving these neurons is essential in properly maintaining energy balance, and any disturbance therein may result in hyperphagia/obesity or hypophagia/starvation. Thus, adequate knowledge of the POMC and NPY/AgRP neuron physiology is mandatory to understand the pathophysiology of obesity and related metabolic diseases. This review will discuss the history and recent updates on the POMC and NPY/AgRP neuronal circuits, as well as the general anorexigenic and orexigenic circuits in the CNS. [BMB Reports 2015; 48(4): 229-233]

• Development and Reproduction
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• v.15 no.2
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• pp.173-178
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• 2011

The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoaminergic neurotoxin with the potential to cause serotonergic neurotoxicity, but has become a popular recreational drug. Little has been known about the cellular effects induced by MDMA. This report shows that MDMA inhibits neuronal cell growth and differentiation. MDMA suppressed neuronal cell growth. The results of quantitative real-time PCR analysis showed that Egr-1 expression is elevated in mouse embryo and neuroblastoma cells after MDMA treatment. Transiently transfected Egr-1 interfered with the neuronal differentiation of neuroblastoma cells such as SH-SY5Y and PC12 cells. These findings provide evidence that the abuse of MDMA during pregnancy may impair neuronal development via an induction of Egr-1 over-expression.

• Molecules and Cells
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• v.20 no.2
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• pp.256-262
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• 2005

The neuronal cytoskeleton is essential for establishment of neuronal polarity, but mechanisms controlling generation of polarity in the cytoskeleton are poorly understood. The nonreceptor tyrosine kinase, Fer, has been shown to bind to microtubules and to interact with several actin-regulatory proteins. Furthermore, Fer binds p120 catenin and has been shown to regulate cadherin function by modulating cadherin-${\beta}$-catenin interaction. Here we show involvement of Fer in neuronal polarization and neurite development. Fer is concentrated in growth cones together with cadherin, ${\beta}$-catenin, and cortactin in stage 2 hippocampal neurons. Inhibition of Fer-p120 catenin interaction with a cell-permeable inhibitory peptide (FerP) increases neurite branching. In addition, the peptide significantly delays conversion of one of several dendrites into an axon in early stage hippocampal neurons. FerP-treated growth cones also exhibit modified localization of the microtubule and actin cytoskeleton. Together, this indicates that the Fer-p120 interaction is required for normal neuronal polarization and neurite development.

• Biomolecules & Therapeutics
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• v.28 no.5
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• pp.381-388
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• 2020

Methamphetamine (METH) is a highly addictive psychostimulant and one of the most widely abused drugs worldwide. The continuous use of METH eventually leads to drug addiction and causes serious health complications, including attention deficit, memory loss and cognitive decline. These neurological complications are strongly associated with METH-induced neurotoxicity and neuroinflammation, which leads to neuronal cell death. The current review investigates the molecular mechanisms underlying METH-mediated neuronal damages. Our analysis demonstrates that the process of neuronal impairment by METH is closely related to oxidative stress, transcription factor activation, DNA damage, excitatory toxicity and various apoptosis pathways. Thus, we reach the conclusion here that METH-induced neuronal damages are attributed to the neurotoxic and neuroinflammatory effect of the drug. This review provides an insight into the mechanisms of METH addiction and contributes to the discovery of therapeutic targets on neurological impairment by METH abuse.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.155-163
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• 1998

The purpose of present study was to compare the effects of somatostatin (SOM) and morphine (Mor) on the responses of wide dynamic range (WDR) cells to peripheral noxious stimulation. Single neuronal activity was recorded with a carbon-filament electrode at the lumbosacral enlargement of cat spinal cord. After identifying WDR cells, their responses to peripheral noxious mechanical or thermal stimuli were characterized and the effects of SOM and Mor, applied either iontophoretically or intrathecally, were studied. In most cells SOM and Mor suppressed noxious stimulus-evoked WDR neuronal activity, though a few WDR neurons showed no change or were excited by SOM and Mor. Systemically applied naloxone, a non-specific opioid antagonist, always reversed the Mor induced suppression of neuronal activity evoked by noxious mechanical stimuli, but did not always reverse the suppression of neuronal activity elicited by SOM. The suppressive effect of Mor on thermal stimulus-evoked neuronal activity was partially reversed by naloxone, while that of SOM were not reversed at all. The above results suggest that both Mor and SOM exert an inhibitory effect on thermal and mechanical stimulus-evoked WDR neuronal activity in cat spinal dorsal horn, but the mechanisms are dependent upon the functional populations of dorsal horn nociceptive neurons.

• Animal cells and systems
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• v.12 no.4
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• pp.203-209
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• 2008

Berberine, an isoquinoline alkaloid found in Coptidis Rhizoma(goldenthread) extract, has multiple pharmacological effects such as anti-inflammatory, antimicrobial and anti-ischemic effects. In the present study, we examined the effects of berberine on neuronal survival and differentiation in a hippocampal precursor cell line and in the memory deficient rat model. Berberine increased in a dose dependent manner the survival of hippocampal precursor cells as well as differentiated cells. In addition, berberine promoted neuronal differentiation of hippocampal precursor cells. In the memory deficient rat model induced by stereotaxic injection of ibotenic acid into entorhinal cortex(Ibo model), hippocampal cells were increased about 2.7 fold in the pyramidal layer of CA1 region and about 2 fold in the dentate gyrus by administration of berberine after 2 weeks of ibotenic acid injection. Furthermore, neuronal cells immunoreactive to calbindin were increased in the hippocampus and entorhinal cortex area by administration of berberine. Taken together, these results suggest that berberine has neuroprotective effect in the Ibo model rat brain by promoting the neuronal survival and differentiation.