• Applied Microscopy
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• v.25 no.1
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• pp.65-74
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• 1995

An immunocytochemical study of GABA-positive neuronal elements was performed at the electron microscopic level to examine subcellular distribution of the inhibitory neurotransmitter in the dog basilar pons. Electron-dense reaction product was observed in neuronal somata and dendritic processes. One or more unlabeled axon terminals made asymmetric synaptic contacts with these GABAergic somatic and dendritic profiles. A large number of GABA-positive axon terminals were also observed. They made symmetric as well as asymmetric synaptic contacts with unlabeled dendritic profiles. In axo-axonic synapses, postsynaptic axon-like processes were consistently GABA-immunoreactive. These observations suggest that the inhibitory local circuit neurons in the dog basilar pons play a major role in cerebro-ponto-cerebellar circuitry by integrating various afferent inputs and conveying them into the cerebellar cortex and the deep cerebellar nuclei.

• Journal of Life Science
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• v.21 no.5
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• pp.647-655
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• 2011

The neurotoxicity of aggregated amyloid ${\beta}$ ($A{\beta}$) has been implicated as a critical cause in the pathogenesis of Alzheimer's disease (AD). It can cause neurotoxicity in AD by evoking a cascade of apoptosis to neuron. Here, we investigated the neuroprotective effects of cilostazol, which acts as a phosphodiesterase III inhibitor, on $A{\beta}_{25-35}$-induced cytotoxicity in mouse neuronal cells and cognitive decline in the C57BL/6J AD mouse model via peroxisome proliferator-activated receptor (PPAR)-${\gamma}$ activation. $A{\beta}_{25-35}$ significantly reduced cell viability and increased the number of apoptotic-like cells. Cilostazol treatment recovered cells from $A{\beta}$-induced cell death as well as rosiglitazone, a PPAR-${\gamma}$ activator. These effects were suppressed by GW9662, an antagonist of PPAR-${\gamma}$ activity, indicative of a PPAR-${\gamma}$-mediated signaling. In addition, cilostazol and rosiglitazone also restored PPAR-${\gamma}$ activity levels that had been altered as a result of $A{\beta}_{25-35}$ treatment, which were antagonized by GW9662. Furthermore, cilostazol also markedly decreased the number of apoptotic-like cells and decreased the Bax/Bcl-2 ratio. Intracerebroventricular injection of $A{\beta}_{25-35}$ in C57BL/6J mice resulted in impaired cognitive function. Oral administration of cilostazol (20 mg/kg) for 2 weeks before $A{\beta}_{25-35}$ injection and once a day for 4 weeks post-surgery almost completely prevented the $A{\beta}_{25-35}$-induced cognitive deficits, as did rosiglitazone. Taken together, our findings suggest that cilostazol could attenuate $A{\beta}_{25-35}$-induced neuronal cell injury and apoptosis as well as promote the survival of neuronal cells, subsequently improving cognitive decline in AD, partly because of PPAR-${\gamma}$ activation. The phosphodiesterase III inhibitor cilostazol may be the basis of a novel strategy for the therapy of AD.

• Journal of Life Science
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• v.32 no.1
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• pp.11-22
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• 2022

N-methyl-D-aspartate (NMDA) receptors have received considerable attention regarding their involvement in glutamate-induced neuronal excitotoxicity. Resveratrol has been shown to exhibit neuroprotective effects against this kind of overactivation, but the underlying cellular mechanisms are not yet clearly understood. In this study, HT-22 neuronal cells were treated with NMDA in Mg²⁺-free buffer and subsequently used as an experimental model of glutamate excitotoxicity to elucidate the mechanisms of resveratrol-induced neuroprotection. We found that NMDA treatment causes a drop in MTT reduction ability, disrupts inside-negative transmembrane potential of mitochondria, depletes cellular ATP levels, and stimulates intracellular ROS production. Double fluorescence imaging studies demonstrated an increased formation of mitochondrial permeability transition (MPT) pores accompanied by apoptotic cell death, while cobalt protoporphyrin and bilirubin showed protective effects against NMDA-induced mitochondrial injury. On the other hand, zinc protoporphyrin IX significantly attenuated the protective effects of resveratrol which was itself shown to enhance heme oxygenase-1 (HO-1) mRNA and protein expression levels. In cells transfected with HO-1 small interfering RNA, resveratrol failed to suppress the NMDA-induced effects on MTT reduction ability and MPT pore formation. The present study suggests that resveratrol may prevent mitochondrial injury in NMDA- treated HT-22 cells and that enhanced expression of HO-1 is involved in the underlying cellular mechanism.

• Journal of Life Science
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• v.19 no.5
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• pp.598-606
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• 2009

Oxidative stress by free radicals is a major cause of neuronal cell death. Excitotoxicity in hypoxia/ischemia causes an increase in reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP), resulting in dysfunction of the mitochondria and cell death. Pinelliae Rhizoma (PR) is a traditional medicine for incipient stroke. We investigated the effects of PR Water-Extract on the modulation of ROS and MMP in a hypoxic model using cultured rat cortical cells. PR Water-Extract was added to the culture medium at various concentrations (0.25${\sim}$5, 5.0 ${\mu}g/ml$) on day in vitro 12(DIV12), given a hypoxic shock (2% $O_2$/5% $CO_2$, $37^{\circ}C$, 3 hr), and cell viability was assessed on DIV15 by Lactate Dehydrogenase Assay (LDH assays). PR Water-Extract showed a statistically significant effect on neuroprotection (10${\sim}$15% increase in viability; p<0.01) at 1.0 and 2.5 ${\mu}g/ml$ in normoxia and hypoxia. Measurement of ROS production by $H_2DCF-DA$ stainings showed that PR Water-Extract efficiently reduced the number and intensity of ROS-producing neurons, especially at 1 hr post shock and DIV15. When MMP was measured by JC-1 stainings, PR Water-Extract efficiently maintained high-energy charged mitochondria. These results indicate that PR Water-Extract protects neurons in hypoxia by preventing ROS production and preserving the cellular energy level.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.506-513
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• 2004

Osteoclast action is necessary for alveolar bone remodeling in orthodontic tooth movement. The nervous system has also been reported to be associated with bone remodeling. This study was aimed to investigate the changes of osteoclasts in the periodontal ligament (PDL) space after surgical resection of the inferior alveolar nerve (IAN). Experimental rats were divided into young and adult groups. A surgical resection procedure of the IAN was carried out in the left side of the mandible and a sham operation in the right side of the mandible. The number of osteoclasts on the bundle bone surface and the resorption activity of the osteoclasts were histomorphometrically measured. The changes in distribution of substance P (SP) immunoreactive (IR) nerve fiber were evaluated in the PDL and pulp. SP-IR nerve fiber was depleted in both the PDL and pulp of the IAN resection side in both groups, which confirmed the resection of IAN to be successfully conducted. The number of osteoclasts in the IAN resection side was significantly reduced in both the young and adult groups (p<0.01 and p<0.05), whereas the resorption activity of osteoclasts did not show any significant difference between the IAN resection side and the sham operation side in both groups (p>0.05 and p<0.05). The adult group showed that the number of osteoclasts reduced significantly (p<0.01) and the resorption activity didn't change in comparison with the young group (p>0.05). These results suggest that surgical resection of the IAN and aging reduce the population of the recruited osteoclasts within the PDL, but don't affect on the osteoclastic resorption activity.

• Korean Journal of Acupuncture
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• v.20 no.2
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• pp.67-76
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• 2003

목적 : 오가피 약침이 알코올에 의해서 중독된 Sprague-Dawley(S-D)계 흰쥐의 해마 치상회에서 새로운 신경세포 생성 및 NOS발현에 미치는 영향을 조사하였다. 방법 : S-D계 흰쥐에 알코올을(2g/kg) 3일간 연속으로 투여한후, 5일간 인체의 중완혈에 상응하는 부위에 오가피 약침(30mg/kg) 치료를 시행하였다. 치료효과를 관찰하기 위해서 BrdU-면역조직화학 염색법 및 NADPH-d-조직화학염색법을 이용하였다. 결과 : 알코올 처치군에서는 BrdU-양성세포수 및 NADPH-양성세포수가 모두 정상군에 비해서 감소한 반면에 알코올 처치후 오가피 약침으로 치료한 군에서는 BrdU-양성세포수 및 NADPH-양성세포수 모두 알코올 처치군에 비해서 증가하였다. 결론 : 오가피 약침치료가 알코올에 의해서 중독된 S-D계 흰쥐 해마 치상회에서 새로운 신경세포의 생성을 증가시키는 것을 확인하였으며, 그 기전으로 산화질소가 관여할 것으로 사려된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.383-391
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• 1995

In order to find out the distribution of neuropeptide Y (NPY) recently known as the gonadotropin (GtH) stimulation neurohormone in the brain tissues of marine teleost, detection and localization of NPY like substance in brain of two rockfish species, Sebastes oblongus and S. schlekeli were done by immunohistochemisty. Distribution of GtH cells in hypophysis were also observed by aldehyde fuchsin (AF)-fast green-orange G stain to compare with gonadal phases of the rockfish species. NPY immunoreactive cells were detected in olfactory bulb, telencephalon and mesencephalon of the brain, and NPY immunoreactive fibers were distributed not only in olfactory bulb, telencephalon and mesencephalon but also in optic nerve, hypothalamus and optic tectum. Regardless of ovarian maturation in two rockfish species, NPY immunoreactive fibers were observed in the neurohypophysis adjacent to the AF negative cells in the rostral pars distalis of hypophysis in both species. Moreover, the fibers were distributed in the rostral and proximal pars distalis near to the GtH cells of the hypophysis in both species possessing the growing or mature oocytes. Slight AF stainable GtH cells were detected in hypophysis of two species before parturition (S. oblongus) and in mature stage (S. schlegeli), but AF stainability of the cells in the proximal pars distalis after parturition was more increased than that of the cells Tn mature stage or before parturition. The size and nucleus diameter of GtH cells in S. oblongus and S. schlegeli before parturition were significantly bigger than those of GtH cells in individuals after parturiton (S. oblongus) or with resting ovary (S. schlegeli) (P<0.01).

• 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 Life Science
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• v.21 no.11
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• pp.1526-1531
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• 2011

Local protein synthesis in neuronal dendrites is important for site-specific regulation of synaptic plasticity. In this study, we investigated whether translation initiation factors (eIFs) are present at the postsynaptic sites. High resolution confocal microscopy showed that the eIF4E and eIF4G (which bind the 5'-terminal mRNA cap), eIF5 (which is important during the 3' direction scanning to find an initiation codon), eIF6 (which mediates upregulation of translation by external stimuli), and eIF5A (which mediate translation upregulation under adverse conditions) were localized to the post-synaptic sites. Immunoblot and detergent extraction experiments also indicated that these eIFs were present in the synapse in association with the postsynaptic density (PSD). Our data provide evidence for the strategic positioning of eIFs at the postsynaptic site for initiation of translation in diverse situations.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.79-83
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• 2008

The present study describes glutamate which is known as excitatory neurotransmitter is related with oxidative damages and the Viola mandshurica extracts. Showed protective effects against glutamate-induced cytotoxicity. The protective effect of antioxidant on the glutamate treated N18-RE-I05 cells was determined by a MTT reduction assay. The neuroprotective effect of methanol, ethanol, and acetone extracts from V. mandshurica against glutamate-induced cytotoxicity was assessed by the results of an MTT reduction assay. Among the three extracts, the acetone extract showed the highest protective effect by the results of an lactate dehydrogenase release assay. Therefore, these results suggest that V. mandshurica extracts could be a new potential candidate against glutamate-induced oxidative stress.