• Applied Microscopy
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• 제42권3호
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• pp.142-146
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• 2012

Doublecortin (DCX) is a microtuble-associated protein that is required for the migration of immature neuroblasts within the chick and mammalian brain. Although it is generally thought that DCX is expressed only in the neuroblasts, some mature neurons maintain DCX expression; for example, horizontal cells in adult rat retina. In this study, we demonstrate that retinal neural progenitors in the early embryonic stage of the chick also expressed DCX, as do developing ganglion cells and horizontal cells in later stages of development. These findings raise the possibility of a role for DCX in retinal neural progenitors, before they become specialized into neuroblasts in the chick.

• 한국동물학회지
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• 제35권2호
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• pp.144-148
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• 1992

Insulin and transfenin (Tf) were found to be essential for suwival and differentiation of brain neuroblasts obtained from chick embryo. This requirement, however, is Changed from insulin to Tf upon neuronal development of the embryo, and this phenomenon is due to the changes in the levels of corresponding receptors. Using cultured neuroblasts, the level of Tf receptor is also found to increase Lvhile that of insulin receptor falls dramatically during the course of the cell differentiation. These results suggest that the development-specific changes in the levels of insulin and Tf receptors in embryo can be reproduced in the culture system during the differentiation period. Because the culture system used was a defined medium and contained no other macromolecules than insulin and Tf, it appears possible that insulin and Tf may act as signalling molecules in the control of neuronal development.

• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.179-186
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• 2013

Neural stem cells are found in adult mammalian brain regions including the subgranular zone (SGZ) of the dentate gyrus (DG) and the subventricular zone (SVZ). In addition to these two regions, other neurogenic regions are often reported in many species. Recently, the subcallosal zone (SCZ) has been identified as a novel neurogenic region where new neuroblasts are spontaneously generated and then, by Bax-dependent apoptosis, eliminated. However, the development of SCZ in the postnatal brain is not yet fully explored. The present study investigated the precise location and amount of neuroblasts in the developing brain. To estimate the importance of programmed cell death (PCD) for SCZ histogenesis, SCZ development in the Bax-knockout (KO) mouse was examined. Interestingly, an accumulation of extra neurons with synaptic fibers in the SCZ of Bax-KO mice was observed. Indeed, Bax-KO mice exhibited enhanced startle response to loud acoustic stimuli and reduced anxiety level. Considering the prevention of PCD in the SCZ leads to sensory-motor gating dysfunction in the Bax-KO mice, active elimination of SCZ neuroblasts may promote optimal brain function.

• 한국동물학회지
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• 제34권2호
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• pp.209-216
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• 1991

신경세포의 분화에 미치는 insulin의 영향을 알아보기 위하여 계배의 단뇌 신경아세포를 serum-free defined medium에서 배양하였다. Immunofluorescence실험을 통하여 신경특이단백질인 MAP-2는 신경아세포의 세포체와 신경돌기에 존재하는 것으로 나타났다. 또한, 배양액내에 insulin의 농도를 증가하면 신경아세포의 신경돌기 형성이 증가할 뿐 아니라 MAP-2의 합성도 증가하였다. 따라서, 신경아세포의 형태적분화와 생화학적 분화는 서로 밀접하게 연관되어 일어나는 것으로 추측되며, insulin은 신경특이단백질의 합성을 촉진시킴으로써 신경아세포가 신경돌기를 형성하며 분화되어 가는데 결정적인 역할을 하는 것으로 보인다.

• The Korean Journal of Pain
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• 제11권1호
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• pp.7-22
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• 1998

The development of the superior cervical ganglion was studied by electron microscopic method in human fetuses ranging from 40 mm to 260 mm of crown-rump length(10 to 30 weeks of gestational age). At 40 mm fetus, the superior cervical ganglion was composed of clusters of undifferentiated cell, primitive neuroblast, primitive supporting cell, and unmyelinated fibers. At 70 mm fetus, the neuroblasts and their processes were ensheated by the bodies or processes of satellite cells. The cytoplasm of the neuroblast contained rough endoplasmic reticulum, mitochondria, Golgi complex, Nissl bodies and dense-cored vesicles. As the neuroblasts grew and differentiated dense-cored vesicles moved away from perikaryal cytoplasm into developing processes. Synaptic contacts between the cholinergic axon and dendrites of postganglionic neuron and a few axosomatic synapses were first observed at 70 mm fetus. At 90 mm fetus the superior cervical ganglion consisted of neuroblasts, satellite cells, granule-containing cells, and unmyelinated nerve fibers. The ganglion cells increased somewhat in numbers and size by 150 mm fetus. Further differentiation resulted in the formation of young ganglion cells, whose cytoplasm was densely filled with cell organelles. During next prenatal stage up to 260 mm fetus, the cytoplasm of the ganglion cells contained except for large pigment granules, all intracytoplasmic structures which were also found in mature superior cervical ganglion. A great number of synaptic contact zones between the cholinergic preganglionic axon and the dendrites of the postganglionic neuron were observed and a few axosomatic synapses were also observed. Two morphological types of the granule-containing cells in the superior cervical ganglion were first identified at 90 mm fetus. Type I granule-containing cell occurred in solitary, whereas type II tended to appeared in clusters near the blood capillaries. Synaptic contacts were first found on the solitary granule-containing cell at 150 mm fetus. Synaptic contacts between the soma of type I granule-containing cells and preganglionic axon termials were observed. In addition, synaptic junctions between the processes of the granule-containing cells and dendrites of postganglionic neuron were also observed from 150 mm fetus onward. In conclusion, superior cervical ganglion cells and granule-containing cells arise from a common undifferentiated cell precursor of neural crest. The granule-containg cells exhibit a local modulatory feedback system in the superior cervical ganglion and may serve as interneurons between the preganglionic and postganglionic cells.

• Applied Microscopy
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• 제28권2호
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• pp.139-158
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• 1998

The development of the superior cervical ganglion was studied by electron microscopic method in human fetuses ranging from 40 mm to 260 mm of crown-rump length (10 to 30 weeks of gestational age). At 40 mm fetus, the superior cervical ganglion was composed of clusters of undifferentiated cell, primitive neuroblast, primitive supporting cell, and unmyelinated fibers. At 70mm fetus, the neuroblasts and their processes were ensheated by the bodies or processes of satellite cells. The cytoplasm of the neuroblast contained rough endoplasmic reticulum, mitochondria, Golgi complex, Nissl bodies and dense-cored vesicles. As the neuroblasts grew and differentiated dense-cored vesicles moved away from perikaryal cytoplasm into developing processes. Synaptic contacts between the cholinergic axon and dendrites of postganglionic neuron and a few axosomatic synapses were first observed at 70 mm fetus. At 90 mm fetus the superior cervical ganglion consisted of neuroblasts, satellite cells, granule-containing cells, and unmyelinated nerve fibers. The ganglion cells increased somewhat in numbers and size by 150 mm fetus. Further differentiation resulted in the formation of young ganglion cells, whose cytoplasm was densely filled with cell organelles. During next prenatal stage up to 260 mm fetus, the cytoplasm of the ganglion cells contained except for large pigment granules, all intracytoplasmic structures which were also found in mature superior cervical ganglion. A great number of synaptic contact zones between the cholinergic preganglionic axon and the dendrites of the postganglionic neuron were observed and a few axosomatic synapses were also observed. Two morphological types of the granule-containing cells in the superior cervical ganglion were first identified at 90 mm fetus. Type I granule-containing cell occurred in solitary, whereas type II tended to appeared in clusters near the blood capillaries. Synaptic contacts were first found on the solitary granule-containing cell at 150 mm fetus. Synaptic contacts between the soma of type I granule-containing cells and preganglionic axon termials were observed. In addition, synaptic junctions between the processes of the granule- containing cells and dendrites of postganglionic neuron were also observed from 150 mm fetus onward. In conclusion, superior cervical ganglion cells and granule-containing cells arise from a common undifferentiated cell precursor of neural crest . The granule-containg cells exhibit a local modulatory feedback system in the superior cervical ganglion and nay serve as interneurons between the preganglionic and postganglionic cells.

• Applied Microscopy
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• 제26권3호
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• pp.349-367
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• 1996

The development of small granule-containing cell in the superior cervical ganglion was studied by electron microscopic method in human fetuses ranging from 40 mm to 260 mm crown rump length (10 to 30 weeks of gestational age). At 40 mm fetus, the superior cervical ganglion was composed of clusters of undifferentiated cells, primitive neuroblasts, and unmyelinated nerve fibers together with blood vessels. At 90 mm fetus, the superior cervical ganglion consisted of neuroblasts, satellite cell, small granule-containing cells, and unmyelinated nerve fibers. Two morphological types of the small granule-containing cells in the superior cervical ganglion were first indentified at 90 mm fetus, but were rare. Type I granule-containing cell occurred in solitary and had long processes, whereas type II cells tend to appeared in clusters near the blood capillaries. The granule-containing cells were characterized by the presence of dense-cored vesicles ranging from $150{\sim}300nm$ in diameter in both the cell bodies and processes. Other organelles included abundant mitochondria, rough endoplasmic reticulum, neurotubules, and widely distributed ribosomes. The granule-containing cells had long processes similar to those found in principal ganglionic cells. They could be identified by their content in dense-cored vesicles. The small granule-containing cells increased somewhat in size and number with increase of fetal age. Synaptic contacts were first found on the solitary granule-containing cell at 150 mm fetus. Synaptic contacts between the soma and processes of type I granule-containing cells and preganglionic axon terminals were observed. In addition, synaptic junctions between the processes of granule-containing cells and presumed dendrite of postganglionic neuron were also observed from 150 mm onward. On the basis of these features type I granule-containing cells could be considered as interneurons. The clusters of type II granule-containing cells were located in the interstitial or subcapsular portions of the ganglion, and had short processes which ended in close relation to fenestrated capillaries. Therefore it may be infer that clusters of type II granule-containing cells have an endocrine function.

• 대한한방내과학회지
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• 제22권2호
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• pp.135-144
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• 2001

Objectives : The purpose of this investigation is to evaluate the effects of Woohwangcheongsim-won on neuronal death of hypoxic E18 cortical neuroblast. Methods : To evaluate the effect of Woohwangcheongsim-won on neuronal death caused by hypoxia, the survival rate of E18 cortical neuroblast was measured with MTT assay and the changes of several synaptic proteins and enzymes were investigated with the immunoblot assays. Results : The E18 cortical neuroblasts were added 50, 100, 500, 1,000, and $5,000{\mu}g/ml$ Woohwangcheongsim-won. They showed neurotoxicity, when the concentration of Woohwangcheongsim-won was above $1,000{\mu}g/ml$. The E18 cortical neuroblasts, which were added 50, 100, and $500{\mu}g/ml$ Woohwangcheongsim-won, were exposed 98% $N_2/5%\;CO_2$ for 3 hours to induce hypoxia, 3 days later, the survival rate of $50{\mu}g/ml$ Woohwangcheongsim-won was 141.5% when compared to the control group. On the immuneblot assays, the expressions of ${\alpha}$CaMKII, NR2A, NR28, PDE2, PSD-95, and eEF-$1{\alpha}$ were increased in normoxia, but those of NR2A, NR2B were decreased in hypoxia when compared to the control group. Conclusions : The data shows that the effects of Woohwangcheongsim-won on neuronal death of hypoxic E18 cortical neuroblast is a significant result.

• BMB Reports
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• 제57권4호
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• pp.182-187
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• 2024

Neural stem cells (NSCs) in the adult hippocampus divide infrequently; the endogenous molecules modulating adult hippocampal neurogenesis (AHN) remain largely unknown. Here, we show that ErbB3 binding protein 1 (Ebp1), which plays important roles in embryonic neurodevelopment, acts as an essential modulator of adult neurogenic factors. In vivo analysis of Ebp1 neuron depletion mice showed impaired AHN with a low number of hippocampal NSCs and neuroblasts. Ebp1 leads to transcriptional repression of Bmp4 and suppression of Ascl1 promoter methylation in the dentate gyrus of the adult hippocampus reflecting an unusually high level of Bmp4 and low Ascl1 level in neurons of Ebp1-deficient mice. Therefore, our findings suggests that Ebp1 could act as an endogenous modulator of the interplay between Bmp4 and Ascl1/Notch signaling, contributing to AHN.

• Applied Microscopy
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• 제30권2호
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• pp.121-139
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• 2000

망막 발육에 관한 연구는 광수용세포와 외망상층에 대해서 집중적으로 연구되어 왔고 내망상층의 연구는 초기 발육에 관한 연구가 보고된 바 있다. 본 연구는 태생 초기부터 말기까지의 인태아를 대상으로 내핵층의 신경모세포의 분화, 발육과 내망상층에서 신경연접 형성 과정을 전자현미경으로 관찰하여 다음과 같은 결과를 얻었다. 좌고 30mm(태령 9주)때 망막은 외신경모세포와 내신경모세포로 분화, 발육하였고 외신경모세포의 분열은 90mm(태령 14주)때까지 진행되었다. Chievitz층은 30mm때, 내망상층은 50mm(태령 11주)때, 외망상층은 150 mm때 각각 형성되었다. 신경절세포는 자유리보솜이 세포 전역에 분포하고 있었고 조면내형질망, 골지장치, 미세소관 및 농소체를 함유하고 있었다. 30mm때 뮐러세포는 신경절세포의 축삭사이로 돌기를 내고 있었고 초자체쪽에서 내경계막을 형성하였으며 90mm때는 뮐러세포의 돌기는 방사상으로 배열하고 있으며 다량의 활면내형질망을 함유하고 있었다. 신경연접은 50mm때 연접막비후는 존재하면서 연접소포를 내포하고 있지 않은 연접이 관찰되었고, 연접소포를 내포하고 있는 보통연접이 90mm때, 리본연접은 150mm때 각각 출현하였다. 260mm(태령 30주)때 연접소포가 없는 연접, 보통연접 및 리본연접 등 성인에서 출현하는 세 가지 연접이 모두 관찰되었다.