• Applied Microscopy
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• v.34 no.4
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• pp.223-230
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• 2004

To identify the structural basis of mutations that affect synaptic transmission we have begun quantitative ultrastructural descriptions of synapses in cultured Drosophila embryonic neurons. In wild-type cultures, synapses are distinguished by the parallel arrangement of a thickened pre- and post synaptic membrane separated by a synaptic cleft. The presynaptic active zones and postsynaptic densities are defined by electron dense material close to the membrane. Presynaptic regions are also characterized by the presence of one or more electron dense regions, presynaptic densities, around which a variable number of small, clear core synaptic vesicles (mean $35.1{\pm}1.44$ nm in diameter) are clustered. Subsets of these vesicles are in direct contact with either the presynaptic density or the membrane and are considered morphologically docked. A small number of larger, dense core vesicles are also observed in most presynaptic profiles.

• Development and Reproduction
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• v.12 no.1
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• pp.31-39
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• 2008

Neural tissue has limited intrinsic capacity of repair after injury, and the identification of alternate sources of neural stem cells has broad clinical potential. We isolated mesechymal-like stem cells from human adipose tissues (AT-MSCs), and studied on transdifferentiation-promoting conditions in neural cells. Dopaminergic and cholinergic neuron induction of AT-MSCs was also studied. Neural differentiation was induced by adding bFGF, EGF, dimethyl sulphoxide (DMSO) and butylated hydroxyanisole(BHA) in N2 Medium and N2 supplement. The immunoreactive cells for $\beta$-tubulin III, a neuron-specific marker, GFAP, an astrocyte marker, or Gal-C, an oligodendrocyte marker, were found. AT-MSCs treated with bFGF, SHH and FGF8 were differentiatied into dopaminergic neurons that were immunopositive for TH antibody. Differentiation of MSCs to cholinergic neurons was induced by combined treatment with basic fibroblast growth factor (bFGF), retinoic acid (RA) and sonic hedgehog (Shh). AT-MSCs treated with DMSO and BHA rapidly assumed the morphology of multipolar neurons. Both immunocytochemistry and RT-PCR analysis indicated that the expression of a number of neural markers including neuro D1, $\beta$-tubulin III, GFAP and nestinwas markedly elevated during this acute differentiation. While the stem cell markers such as SCF, C-kit, and Stat-3 were not expressed after preinduction medium culture, we confirmed the differentiation of dopaminergic and cholinergic neurons by TH/$\beta$-tubulin III or ChAT/ $\beta$-tubulin III positive cells. Conclusively, AT-MSCs can be differentiated into dopaminergic and cholinergic neuronsand these findings suggest that AT-MSCs are alternative cell source of treatment for neurodegenerative diseases.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.147-147
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• 1993

신생쥐의 DRG 배양에서 접종후 1일째 neurite의 형성을 관찰할수 있었고 배양한 세포가 신경세포임을 확인하기 위하여 신경섬유에 대한 항체를 이용한 조직화학적 실험을 실시한 결과 붉게 염색된 세포를 볼 수 있었으므로 이 세포들이 DRG신경세포임을 확인할 수 있었다. 배양한 신경세포중 capsaicin에 대한 감수성을 갖는 신경세포군을 확인하기 위하여 cobalt stain 방법으로 실험한 결과 capsaicin에 대한 감수성율 갖는 신경세포룰 관찰할 수 있었고 비교를 위하여 함께 실험한 resiniferatoxin, KR 25018, 6-paradol, NE-19550, RDL-201등의 capsaicin 유사체들의 경우도 정도는 달리 하였으나 유사한 반응을 보였으므로 일차배양한 신경세포에 대한 작용이 capsaicin의 작용과 같을 가능성을 보여주었다. 진통효과 검정결과 진통효과가 있는 것으로 확인된 capsaicin 구조 유사체들인 resiniferatoxin, 6-paradol, NE-19550, RDL-201, KR-25018모두 농도 의존적인 반응을 보였다. 또한 칼슘 도입을 위해 요구되는 관능기로는 알킬측쇄와 P-위치의 수산기, 3-methoxy기 및 acyl amide 구조가 중요하였다. 알킬측쇄는 NVA의 경우처럼 탄소 8개 정도가 적당했으나 구조적으로 현저히 다른 치환기를 가진 resiniferatoxin이나 KR-25018의 경우에도 유효하였다. Vanillin환의 P-수산기도 필수적이었고 3-methoxy기의 존재시에는 칼슘 도입효과가 강하였다. Acyl amide 결합도 중요하나 필수적은 아니였다.

• Journal of Life Science
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• v.29 no.12
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• pp.1329-1336
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• 2019

Subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) which self-renew and differentiate to neurons and glial cells during postnatal period and throughout adulthood. Since fate decision to either proliferation or differentiation has to respond to intracellular and extracellular conditions, many intrinsic and extrinsic factors are involved. Among them, mitochondria have been reported to participate in fate decision of NSCs. In our previous report, we showed that long-term treatment of a mitochondrial inhibitor rotenone greatly inhibited neurogenesis. In this study, we examined the effects of short-term treatment of rotenone on SVZ NSCs. We found that (1) even one-day treatment of rotenone significantly reduced neurogenesis and earlier time points seemed to be more sensitive to rotenone, (2) a number of Mash1+ transit amplifying cells was decreased by one-day treatment of rotenone, (3) short-term treatment of rotenone eliminated most of the differentiated Tuj1+ neurons and Olig2+ oligodendrocytes, while glial fibrillary acidic protein (GFAP)+ astrocytes were not affected, and (4) sulfiredoxin 1 (Srxn1) gene expression was increased after one-day treatment of rotenone, indicating activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. All these results confirm that functional mitochondria are necessary during differentiation to neurons or oligodendrocytes as well as maintenance of neurons after differentiation. Also, these data suggest that temporary exposure to mitochondrial inhibitor such as rotenone might have long-term effects on neurogenic potential of NSCs.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.269-269
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• 2004

배아줄기 세포는 신경퇴행성 질환의 치료 수단으로 많은 가능성을 가지고 있는 것으로 알려져 있다. 본 연구에서는 중풍 동물모델에서 수중미로 학습을 이용하여 중풍 치료제로서 인간배아줄기 세포의 인지 및 기억력 장애에 대한 기능 회복의 효능을 검토하였고, 인간배아줄기 세포의 신경세포 보호효과를 규명하기 위하여 면역조직화학 염색법을 이용하여 해마내의 세포사멸을 측정하였으며, 인지 및 기억증진의 작용을 규명하기 위하여 아세틸콜린성 신경세포의 활성도를 측정하였다. (중략)

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.209-216
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• 1991

To examine the effed of Insulin on neuronal differentiation, telencephalic neuroblasts from chick embryonic brains were cultured in a serum-free medium. Indirect immunofluorescence microscopic studies revealed that the spedfic protein, MAP-2, was localized in both cell bodies and neurites of developing neuroblasts. Furthermore, treatinent of increasing concentration of Insulin promoted the MAP-2 synthesis as well as the neurite outgrowth activity. Thus, the enhancement of the morphological and biochemical parameters for neuronal differentiation appears to he closely correlated, and the neurotrophic effect of insulin may play a crucial role in neuronal process formation.

• The Korean Journal of Malacology
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• v.16 no.1_2
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• pp.1-9
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• 2000

The visceral ganglion and the right parietal ganglion of the African giant snail, Achatina fulica, consists of two hemispheres, each in left and right side, respectively, like a butterfly. The surface of cortex and medulla in the two ganglions are crowded with nerve cells, but nerve fibers form a network at the middle portion. The nerve cells in the cortex and medulla of the visceral ganglion and the right parietal ganglion are classified into the following four classes according to their sizes: giant (above 200 ${\mu}{\textrm}{m}$, in diameter), large (60-70 ${\mu}{\textrm}{m}$, in diameter), middle (30-40 ${\mu}{\textrm}{m}$, in diameter) and small (10-15 ${\mu}{\textrm}{m}$, in diameter) nerve cells, respectively. The giant and large nerve cells are rarely found(20-22 eas. in total) while the middle and small nerve cells are found in large quantities (middle: 400-500 eas., small: 700-800 eas.). In the AB/AY double staining, the giant nerve cell is identified as light yellow cells (LYC), while large and middle none cells as dark green cells (DGC) or yellow green cells (YGC), and small nerve cells as yellow cells (YC) or blue cells (BC), The DGC, which reacts positively to somatostatin immunostain reaction, inhibits the secretion of the growth control hormone. The giant and large nerve cells are identified to do the functions of phagocytosis as well as neurosecretion.

• Applied Microscopy
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• v.35 no.3
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• pp.165-176
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• 2005

Studies on molecular plasticity of Bermann glia (BG) after harmaline-induced Purkinje cell (PC) degeneration in the rat cerebellum. The intimate structural relationship between BG and PC, evidenced by the sheathing of the PC dendrites by veil-like process from the BG has been suggestive of the close functional relationship between these two cell types. However, little is known about metabolic couplings between these cells. This study designed to investigate molecular plasticity of BG in the rat cerebellum in which PCs were chemically ablated by harmaline treatment. Immunohistochemical examination reveals that harmaline induced PC degeneration causes a marked glial reaction in the cerebellum with activated BG and microglia aligned in parasagittal stripes within the vermis. In these strips, activated BG were associated with upregulaion of metallotheionein, while GLAST and was down regulated, as compared with nearby intact area where both BG are in contact with PCs. The data from this study demonstrate that BG can change their phenotypic expression when BG loose their contact with PCs. It is conceivable that activated BG may upregulate structural proteins, metallothionein expression to use for their proliferation and hypertrophy; metallothionein expression to cope with oxidative stress induced by PC degeneration and microglial activation. On the contrary, BG may down regulated expression of GLAST because sustained loss of contact with PCs would eliminate the necessity for the cellular machinery involved glutamate metabolism. In conclusion, BG might respond man to death of PCs by undergoing a change in metabolic state. It seems possible that signaling molecules released from PCs regulates the phenotype expression of BG. Also ultrastructures in the organelles of normal PC and BG are distinguished by mitochondrial appearance, and distributed vesicles at the synaptic area in the cytoplasm.

• Journal of Life Science
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• v.27 no.6
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• pp.623-631
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• 2017

In the subventricular zone (SVZ) and the subgranular zone of the brain, neurogenesis occurs throughout one's lifespan. Neural stem cells (NSCs) in these regions divide to maintain their stem cell pools as well as differentiate into neurons and glial cells. To monitor cell division, a thymidine analogue such as 5-ethynyl-2'-deoxyuridine (EdU) has been used. In some cases, EdU was applied to label newly born neurons. Here, we report about the effects of EdU on the proliferation and differentiation of NSCs cultured from mouse SVZ. First, when NSCs were cultured in a proliferation medium containing EdU for 24 hr, they did not generate any neurons under the following differentiation conditions. When EdU was applied to the proliferating NSCs for 1 hr prior to differentiation, neurogenesis was still substantially reduced. Second, EdU decreased cell proliferation of NSCs in dose- and time-dependent manners. Finally, EdU inhibited differentiation into oligodendrocyte lineage, while the number of glial fibrillary acidic protein (GFAP)-positive astrocytes increased. To our knowledge, these findings are the first to show the effects of EdU on the differentiation of SVZ NSCs and suggest that cell division is necessary for differentiation into neurons and oligodendrocytes.

• Applied Microscopy
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• v.29 no.3
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• pp.383-403
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• 1999

This study was performed to investigate the immunohistochemical and ultrastructural characterization of the choline acetyltransferase (ChAT)-immunoreactive nerve cells in the diagonal band of Broca of the rat basal forebrains, utilizing techniques of immunohistochemical and immunocytochemical microscopy. The ChAT-immunoreactivities were shown within neuronal cell bodies and processes by the light micoscope. According to cell shape and ratio of long axis vs short axis of cell body, the ChAT-immunoreaclive nerve cells in both vertical and horizontal limbs of the diagonal band of Broca were classified into 6 types. at the light microscopic level; round, oval, elongated, fusiform, triangular and polygonal types. As a result of the electron microscopic observation, the ChAT-immunoreactivated products appeared on the outer nuclear envelope, membranes of rough endoplasmic reticula (rER), free ribosomes and polysomes. Each cell type was subdivided into subtype I and II according to the several criteria such as volume of cell body, nuclear size relative to the cytoplasm, kinds and distribution of cell organelles and numbers and sorts of synapses. The subtype I of immnunoreactive nerve cells had large cell body and a small nucleus showing shallow indentations of nuclear evelope. In this subtype I with abundant cytoplasm, rER were well differentiated. Their long cisternae were parallelly ditributed and lamellated. One or two lamellar bodies and nematosomes were observed. The subtype II cell had small cell body and a large nucleus with deep indentations of nuclear envelope. In this subtype II with small cytoplasm, the rER were irregularly distributed and the lamellar body and nematosome were not found. A few axosomatic synapses in the subtype I and II were shown to be symmetric or asymmetric. The ratios of the symmetric synapse to the asymmetric one were investigated to be 1 : 2 and 1 : 4 in the subtype I and II, respectively. The axodendritic ones were almost asymmetric. But, the fusiform and triangular immunoreactive nerve cells were shown only to be subtype I. According to observations in this study, it is considered that the ultrastructural characterization in the 2 subtypes of each cell type may reflect the differences of the metabolic activities and projecting distances to the target cells.