• Applied Microscopy
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• v.42 no.3
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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.

• The Korean Journal of Zoology
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• v.35 no.2
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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.

• Development and Reproduction
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• v.17 no.3
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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.

• 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 Pain
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• v.11 no.1
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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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• v.28 no.2
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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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• v.26 no.3
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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.

• The Journal of Internal Korean Medicine
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• v.22 no.2
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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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• v.57 no.4
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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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• v.30 no.2
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• pp.121-139
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• 2000

The morphogenesis of neuroblasts and plexiform layers, and establishment of its synapses were studied by electron microscopy in human embryos and fetuses ranging from 10 mm to 260 mm crown-rump length ($5\sim30$ weeks of gestational age). At 30 mm fetus the developing retina was composed of outer and inner neuroblastic layers . Cell division of outer neuroblast was occurred until 90 mm fetus. The transient layer of Chievitz was formed by 30 mm fetus, inner plexiform layer by 50 mm fetus, and outer plexiform layer by 150 mm fetus. The cytoplasm of differentiating ganglion cells contained ribosomes, rough endoplasmic reticula, Golgi complexes, microtubules and dense bodies. The processes of $M\ddot{u}ller$ cell penetrated between groups of ganglion cell axons, and formed the cellular component of the inner limiting membrane at 30 mm fetus. At 90 mm fetus radial fibers of M ller cells contained extensive smooth endoplasmic reticula and microtubules. In each specimen , apposing paired membrane specializations were classified as junctions without synaptic vesicles, conventional synapses and ribbon synapses. At 50 mm fetus the processes of neuroblasts in inner plexiform layer were interconnected by junctions without synaptic vesicles. Conventional synapses developed by addition of synaptic vesicles to initially vesicle-free junctions at 90 mm fetus. At 150 mm fetus ribbon synapses were first recognized by the inclusion of a prominent electron-dense material associated with synaptic vesicles. By 260 mm fetus conventional and ribbon synapses and junctions without synaptic vesicles formed similar to those found in the adult.