• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.457-466
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• 2001

Glutamate is the most common excitatory amino acid in the brain. Responsiveness of dendrites to the glutamate greatly varies depending on the application sites. Especially, a point of the maximal response to the glutamate of the dendrite is called as 'hot spot'. In our experiment, the responsiveness of the hot spot to the glutamate was investigated in the CA1 pyramidal neuron of the rat hippocampal slice. CNQX, the antagonist of AMPA receptor, blocked 95% of membrane current to the glutamate focal application $(I_{gl}).$ Train ejection of glutamate on one point of the dendrite increased or decreased the amplitude of $I_{gl}$ with the pattern of train, and the changes were maintained at least for 30 min. In some cases, glutamate train ejection also induced calcium dependent action potentials. To evoke long-term change of synaptic plasticity, we adopted ${\theta}-burst$ in the glutamate train ejection. The ${\theta}-burst$ decreased the amplitude of glutamate response by 60%. However, after ${\theta}-burst$ glutamate train ejection, the calcium dependent action potential appeared. These results indicated that the focal application of glutamate on the neuronal dendrite induced response similar to the synaptic transmission and the trains of glutamate ejection modulated the change of AMPA receptor.

• Journal of Oriental Neuropsychiatry
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• v.21 no.1
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• pp.109-124
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• 2010

Objectives: This experiment was designed to investigate the effect of the InSamYangYoung-tang(Renshenyangrongtang) extract on $A{\beta}$-induced AD model. Methods: The effects of the InSamYangYoung-tang(Renshenyangrongtang) extract on neural damages of cultured PC12 cells induced by $A{\beta}$ were investigated. The effects of the InSamYangYoung-tang(Renshenyangrongtang) extract on neural damages of hippocampal and cortical neurons in the mouse induced by $\beta$-amyloid were investigated. Results: 1. $A{\beta}$ treatment into neuronal cells activated cell death pathway when analyzed by MTT assay and by histological analysis. Then InSamYangYoung-tang(Renshenyangrongtang) treatment improved cell survival to a similar level as in normal group. 2. $A{\beta}$ treatment increased caspase 3 protein levels but decreased phospho-Erk1/2 in neuronal cells. InSamYangYoung-tang(Renshenyangrongtang) treatment reversed the production levels of two proteins close to those in normal group. 3. $A{\beta}$ treatment induced the atrophy of neuronal cells in terms of neuronal processes and cell body shrinkage, but InSamYangYoung-tang(Renshenyangrongtang) greatly improved their morphology. 4. Neuroprotective activity, as observed in InSamYangYoung-tang(Renshenyangrongtang)-treated groups, was similarly observed in cells treated with galantamine which was used as a positive control. Moreover, overall recovery pattern by InSamYangYoung-tang(Renshenyangrongtang) was similar between cultured PC12 cells and in vivo hippocampal and cerebral cortical neurons in the mouse brain. Conclusions: This experiment shows that the InSamYangYoung-tang(Renshenyangrongtang) may play a protective role in neural tissues damaged by cytotoxic substances. Since neuronal damage seen in degenerative brains such as AD are largely unknown, the current data may provide possible insight into therapeutic strategies for AD treatments. InSamYangYoung-tang(Renshenyangrongtang) might be effective for the treatment of AD. Investigation into the clinical use of the InSamYangYoung-tang(Renshenyangrongtang) for AD is suggested for future research.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.1
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• pp.63-70
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• 2018

Cilostazol is a selective inhibitor of type 3 phosphodiesterase (PDE3) and has been widely used as an antiplatelet agent. Cilostazol mediates this activity through effects on the cyclic adenosine monophosphate (cAMP) signaling cascade. Recently, it has attracted attention as a neuroprotective agent. However, little is known about cilostazol's effect on excitotoxicity induced neuronal cell death. Therefore, this study evaluated the neuroprotective effect of cilostazol treatment against hippocampal neuronal damage in a mouse model of kainic acid (KA)-induced neuronal loss. Cilostazol pretreatment reduced KA-induced seizure scores and hippocampal neuron death. In addition, cilostazol pretreatment increased cAMP response element-binding protein (CREB) phosphorylation and decreased neuroinflammation. These observations suggest that cilostazol may have beneficial therapeutic effects on seizure activity and other neurological diseases associated with excitotoxicity.

• Journal of Life Science
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• v.18 no.11
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• pp.1479-1484
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• 2008

Deep seawater (DSW) refers to water extracted from the ocean, usually at depths of 200 meters or more, which is rich in inorganic materials and has attracted attention for various applications. We investigated the effects of the DSW on the synaptic maturation of cultured rat hippocampal neurons. Immunocytochemical examination of DIV21 showed that PSD-95, $\alpha$CaMKII, and synGAP$\alpha1$clusters were strengthened and coupling rates of SV2 and NR2B were significantly increased in neurons grown in the presence of H-800 and H-1000 DSW. Our results indicate that DSW promotes the formation of excitatory postsynaptic signal transduction complexes NRC/MASC and functional synapses.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.3
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• pp.285-296
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• 1997

Injury to brain transforms resting astrocytes to their reactive form, the hallmark of which is an increase in glial fibrillary acidic protein (GFAP), the major intermediate filament protein of their cell type. The overall glial response after brain injury is referred to as reactive gliosis. Glial-neuronal interaction is important for neuronal migration, neurite outgrowth and axonal guidance during ontogenic development. Although much attention has been given to glial regulation of neuronal development and regeneration, evidences also suggest a neuronal influence on glial cell differentiation, maturation and function. The aim of the present study was to analyze the effects of glial-hippocampal neuronal co-culture on GFAP expression in the co-cultured astrocytes. The following antibodies were used for double immunostaining chemistry; mouse monoclonal antibodies for confirm neuronal cells, rabbit anti GFAP antibodies for confirm astrocytes. Primary cultured astrocytes showed the typical flat polygonal morphology in culture and expressed strong GFAP and vimentin. Co-cultured hippocampal neurons on astrocytes had phase bright cell body and well branched neurites. About half of co-cultured astrocytes expressed negative or weak GFAP and vimentin. After 2 hour glutamate (0.5 mM) exposure of glial-neuronal co-culture, neuronal cells lost their neurites and most of astrocytes expressed strong CFAE and vimentin. In Western blot analysis, total GFAP and vimentin contents in co-cultured astrocytes were lower than those of primary cultured astrocytes. After glutamate exposure of glial-neuronal co-culture, GFAP and vimentin contents in astrocytes were increased to the level of primary cultured astrocytes. These results suggest that neuronal cell decrease GFAP expression in co-cultured astrocytes and hippocampal neuronal-glial co-culture can be used as a reactive gliosis model in vitro for studying GFAP expression of astrocytes.

• Journal of Life Science
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• v.18 no.6
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• pp.897-901
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• 2008

Deep seawater (DSW; deep ocean water) is pure, rich in inorganic materials which have attracted attention for various applications. In this study we investigated the effects of the DSW upwelled from the East Sea, offshore Yang Yang (Korea) on the morphological differentiation of cultured rat hippocampal neurons, which were grown in the minimal essential medium containing 10% (v/v) fetal bovine serum and 25% (v/v) DSW with various hardness. DSW had no effect on initial morphological differentiation (17 hr post-plating). When observed on DIV3, 7, 14, and 17, low hardness (0 and 200) DSW reduced dendritic branching. However, dendritic branches within $80\;{\mu}m$ diameter from the center of soma nearly doubled in neurons grown in hardness 1,000 DSW-containing media. DSW with hardness 600 was more or less same as control groups. These results indicate that DSW with appropriate hardness ameliorates neuronal health.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.174-179
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• 2014

Since in vitro neural recording and imaging applications based on a surface plasmon resonance (SPR) technique have expanded dramatically in recent years, cytotoxicity assessment to ensure the biosafety and biocompatibility for those applications is crucial. Here, we report the cytotoxicity of the SPR substrate incorporating a flint glass whose refractive index is larger than that of a conventional crown glass. A high refractive index glass substrate is essential in neural signal detection due to the advantages such as high sensitivity and wide dynamic range. From experimental data using primary hippocampal neurons, it is found that a lead-based flint glass is not appropriate as a neural recording template although the neuron cells are not directly attached to the toxic glass. We also demonstrate that the adhesion layer between the glass substrate and the gold film plays an important role in achieving the substrate stability and the cell viability.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.2
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• pp.43-49
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• 2008

Flavonoids have been shown to affect calcium signaling in neurons. However, there are no reports on the effect of apigenin on glutamate-induced calcium signaling in neurons. We investigated whether apigenin affects glutamate-induced increase of free intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) in cultured rat hippocampal neurons, using fura-2-based digital calcium imaging and microfluorimetry. The hippocampal neurons were used between 10 and 13 days in culture from embryonic day 18 rats. Pretreatment of the cells with apigenin ($1{\mu}M$ to $100{\mu}M$) for 5 min inhibited glutamate ($100{\mu}M$, 1 min) induced $[Ca^{2+}]_i$ increase, concentration-dependently. Pretreatment with apigenin ($30{\mu}M$) for 5 min significantly decreased the $[Ca^{2+}]_i$ responses induced by two ionotropic glutamate receptor agonists, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA, $10{\mu}M$, 1 min) and N-methyl-D-aspartate (NMDA, $100{\mu}M$, 1 min), and significantly inhibited the AMPA-induced peak currents. Treatment with apigenin also significantly inhibited the $[Ca^{2+}]_i$ response induced by 50 mM KCl solution, decreased the $[Ca^{2+}]_i$ responses induced by the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxy-phenylglycine (DHPG, 100 $[Ca^{2+}]_i$, 90 s), and inhibited the caffeine (10 mM, 2 min)-induced $[Ca^{2+}]_i$ responses. Furthermore, treatment with apigenin ($30{\mu}M$) significantly inhibited the amplitude and frequency of 0.1 mM $[Mg^{2+}]_o$-induced $[Ca^{2+}]_i$ spikes. These data together suggest that apigenin inhibits glutamate-induced calcium signaling in cultured rat hippocampal neurons.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.12-17
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• 2007

Curcumin is a natural phenolic yellow curry spice, derived from the tumeric, which has been used for the treatment of diseases associated with oxidative stress and inflammation. Curcumin is known to have both anti-oxidative and anti-inflammatory properties. These properties can be beneficial to protect the brain from the neurodegenerative diseases. We now report the neuroprotective effects of curcumin pretreatment in primary hippocampal neurons to glutamate-induced excitotoxicity. Pretreatment of embryonic mouse hippocampal cell cultures with low does of curcumin protected neurons against glutamate-induced death, however, this neuroprotection was not correlated with the modulation of oxidative stress. Interestingly, high dose of curcumin showed the cytotoxicity in primary cultured hippocampal neurons. Immunoblot analyses showed that levels of stress response. protein HSP70 were significantly elevated in neurons exposed to low dose of curcumin, whereas levels of cleaved PARP were increased in neurons exposed to high dose of curcumin. These findings show that curcumin can modulate neuronal responses to glutamate, and suggest possible use of curcumin and related compounds in the prevention and/or treatment of neurodegenerative disorders.

• BMB Reports
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• v.50 no.3
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• pp.109-110
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• 2017

The nature of encoded information in neural circuits is determined by neuronal firing patterns and frequencies. This paper discusses the molecular identity and cellular mechanisms of spike-frequency adaptation in the central nervous system (CNS). Spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is mediated by the $Ca^{2+}$-activated $Cl^-$ channel (CACC) anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in increased number of spikes, in conjunction with significantly reduced spike-frequency adaptation. No study has so far demonstrated that CACCs mediate afterhyperpolarization currents, which result in the modulation of neuronal spike patterns in the CNS. Our study therefore proposes a novel role for ANO2 in spike-frequency adaptation and transmission of information in the brain.