• Applied Microscopy
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• v.40 no.1
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• pp.15-19
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• 2010

The present study was designed to demonstrate ionic zinc in the rat DRG by means of zinc selenium autometallography($ZnSe^{AMG}$). Ganglion cells varied in size from 15 to 100 ${\mu}m$. The smaller neurons were strongly stained with AMG, whereas the larger cells were weakly stained. Each large ganglion cell was surrounded by perineuronal satellite cells, showing apparent AMG staining. We demonstrated for the first time the existence of zinc-containing satellite cells in the rodent DRG. Using electron microscopy, fine AMG grains were observed scattered in the somata of the DRG neurons, especially small cells. However, much lower concentrations of the AMG grains occupied in the large cells, and these were mostly localized in lysosome-like organelles. These results indicate that zinc may be involved in sensory transmission in the DRG level.

• Molecules and Cells
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• v.37 no.8
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• pp.613-619
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• 2014

The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ~12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.

• Clinical and Experimental Otorhinolaryngology
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• v.11 no.4
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• pp.224-232
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• 2018

Objectives. Spiral ganglion neurons (SGNs) include potential endogenous progenitor populations for the regeneration of the peripheral auditory system. However, whether these populations are present in adult mice is largely unknown. We examined the presence and characteristics of SGN-neural stem cells (NSCs) in mice as a function of age. Methods. The expression of Nestin and Ki67 was examined in sequentially dissected cochlear modiolar tissues from mice of different ages (from postnatal day to 24 weeks) and the sphere-forming populations from the SGNs were isolated and differentiated into different cell types. Results. There were significant decreases in Nestin and Ki67 double-positive mitotic progenitor cells in vivo with increasing mouse age. The SGNs formed spheres exhibiting self-renewing activity and multipotent capacity, which were seen in NSCs and were capable of differentiating into neuron and glial cell types. The SGN spheres derived from mice at an early age (postnatal day or 2 weeks) contained more mitotic stem cells than those from mice at a late age. Conclusion. Our findings showed the presence of self-renewing and proliferative subtypes of SGN-NSCs which might serve as a promising source for the regeneration of auditory neurons even in adult mice.

• Applied Microscopy
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• v.48 no.1
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• pp.17-26
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• 2018

The characteristic features of the arachnid central nervous system (CNS) are related to its body segmentation, and the body in the Opiliones appears to be a single oval structure because of its broad connection between two tagmata (prosoma and opisthosoma). Nevertheless, structural organization of the ganglionic neurons and nerves in the harvestman Leiobunum japonicum is quite similar to the CNS in most other arachnids. This paper describes the fine structural details of the main groups of neuropiles in the CNS ganglia revealed by the transmission electron microscopy. In particular, electron-microscopic features of neural clusters in the main neuroganglia of the CNS (supraesophageal ganglion, protocerebral ganglion, optic lobes, central body, and subesophageal ganglion) could provide indications for the nervous pathways associated with nerve terminations and plexuses. The CNS of this harvestman consists of a supraesophageal ganglion (brain) and a subesophageal mass, and there are no ganglia in the abdomen. Cell bodies of neuroganglia are found in the periphery, but central parts of the ganglia are mostly fibrous in all ganglia. Neuroglial cells occupy the spaces left by nerve cells. Since the nerve cells in the ganglia are typical composed of monopolar neurons, axons and dendrites of neurons are distributed along the same direction.

• Journal of Ginseng Research
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• v.48 no.2
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• pp.163-170
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• 2024

Background: Mechanisms of synaptic plasticity in retinal ganglion cells (RGCs) are complex and the current knowledge cannot explain. Growth and regeneration of dendrites together with synaptic formation are the most important parameters for evaluating the cellular protective effects of various molecules. The effect of ginsenoside Rg1 (Rg1) on the growth of retinal ganglion cell processes has been poorly understood. Therefore, we investigated the effect of ginsenoside Rg1 on the neurite growth of RGCs. Methods: Expression of proteins and mRNA were detected by Western blot and qPCR. cAMP levels were determined by ELISA. In vivo effects of Rg1 on RGCs were evaluated by hematoxylin and eosin, and immunohistochemistry staining. Results: This study found that Rg1 promoted the growth and synaptic plasticity of RGCs neurite by activating the cAMP/PKA/CREB pathways. Meanwhile, Rg1 upregulated the expression of GAP43, Rac1 and PAX6, which are closely related to the growth of neurons. Meantime, H89, an antagonist of PKA, could block this effect of Rg1. In addition, we preliminarily explored the effect of Rg1 on enhancing the glycolysis of RGCs, which could be one of the mechanisms for its neuroprotective effects. Conclusion: Rg1 promoted neurite growth of RGCs through cAMP/PKA/CREB pathways. This study may lay a foundation for its clinical use of optic nerve diseases in the future.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.607-621
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• 1997

GRP was known as the modulator of Pain transmission in central nervous system and local effector to peripheral tissue causing vasodilation, increased blood flow, modulation of immune sysem, stimulation of endothelial cell proliferation, and stimulation of bone formation. Numerous study, therefore, were done to elucidate involvement of CGRP to tooth movement. To investgate the response of CGRP immunoreactive nerve cells according to cell size in trigeminal ganglion during tooth movement, immunohistochemical study was performed using rat. Experimental rats(9 weeks old, 210 gm) were divided as six groups(normal(n=6), 3 hour group(n=5), 12 hour group(n=4), 1 day group(n=5), 3 day group(n=5), 7 day group(n=5)), and were applied orthodontic force (approximately 30 gm) to upper right maxillary molar. After frozen sections of trigeminal ganglions were immunostained using rabbit antisera, the changes of CGRP immunoreactive cells in regard to cell size distribution(small cell(upto $20{\mu}m$), medium cell($20-35{\mu}m$), large cell(above $35{\mu}m$)) were observed. The results were as follows 1. The percentage of CGRP immunoreactive cells to all nerve cells in trigeminal ganglion was 33.0% in normal control group, was decreased to 24.5% in 1 day group, and was increased to 41.8% in 7 day group. 2. The percentage of small, medium, and large cells expressing CGRP immunoreactivity in normal trigeminal ganglion to all CGRP immunoreactive cells were 51.3%, 44.0%, 4.7%, respectively. 3. The percentage of small cells with CGRP immunoreactivity to all CGRP immunopositive cells was increased in 3 hour and 12 hour groups. 4. The percentage of medium cells with CGRP immunoreactivity was increaed in 3 day and 7 day groups. 5. The percentage of large cells with CGRP immunoreactivity was increaed in 7 day group. Conclusively, the small cells with CGRP immunoreactivity in trigeminal ganglion respond to orthodontic force during initial phase of tooth movement, and later the medium and large cells with CGRP immunoreactivity respond

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.25-31
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• 2001

The purpose of this study was to investigate the distribution and fluorescence intensity of vasoactive intestinal polypeptide immunoreactive (VIP-IR) cells in rat trigeminal ganglion following pulp extirpation of rat mandibular molar. The animals were divided into control group(n=6) and experimental group(n=6). The experimental animals were sacrificed at 14 days after pulp extirpation. The trigeminal ganglion was removed and immersed in the 4% paraformaldehyde in 0.1M phosphate buffer. Serial frozen sections about $20{\mu}m$ in thickness were cut with a cryostat. The immunofluorescence staining was performed. The rabbit anti-VIP(1 : 8,000) was used as primary antibody and fluorescene isothiocynate(FITC) conjugated anti-rabbit IgG(1 : 80) as secondary antibody. The slides were observed under confocal laser scanning microscope (CLSM). Unprocessed optical sections were obtained and stored on a optical disk. Color pictures were printed by a video copy processor. The results were as follows; 1. The positive ratio of VIP-IR cells in mandibular part of trigeminal ganglion were 7.40% in control group and 28.42% in experimental group(14 days after pulp extirpation). 2. The relative fluorescence intensity of VIP-IR cells in mandibular part of trigeminal ganglion were 87.78 in control group and 138.65 in experimental group. The relative fluorescence intensity of experimental group was 58% higher than that of control group. 3. In optical serial section analysis of VIP-IR cells of experimental group, most of the 9 sections showed high fluorescence intensity. At high magnification, axons of the experimental group displayed greater VIP-IR than in the control group, and the positive cells were mainly of medium size. The result indicate that number and fluorescence intensity of VIP-IR cells were increased in the mandibular part of trigeminal ganglion following pulp extirpation of mandibular molar, and it suggests that VIP could play a role in processing of nociception.

• Applied Microscopy
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• v.26 no.2
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• pp.137-155
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• 1996

The development of the ganglia of the trachea was studied by electron microscopy in human fetuses ranging from 40 mm to 260 mm crown rump length. At 40 mm fetus, the tracheal ganglia was observed in the submucosa of the trachea. The primitive ganglia consisted of neuroblasts, undifferentiated cells, and unmyelinated nerve fibers. At 50 mm fetus, the neuroblast and their processes in the tracheal ganglia ware ensheathed by the bodies or processes of satellite cells. The cytoplasm of the neuroblast contained rough endoplasmic reticulum, mitochondria, Golgi complex, and ribosomes. At 70 mm fetus, cholinergic and adrenergic axon terminals were observed. Cholinergic axon terminals with agranular vesicles were abundant in the tracheal ganglia with increasing age. During next prenatal stage from 100 mm fetus, the ganglion cells and its processes were completely covered by a thin processes of the satellite cells. Unmyelinated nerve fibers were also completely ensheathed by processes of Schwann cell. Synaptic contacts between the cholinergic axon and dendrite of ganglion cells and a few dendrodendritic synapses were first observed at 100 mm fetus. The granule-containing cells were first identified in the tracheal ganglia at 200 mm fetus. These findings indicate that tracheal ganglia of human fetus resembles other parasympathetic and sympathetic ganglia, but not the enteric ganglia.

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.126-131
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• 2013

Neuropathic pain is a chronic pain disorder caused by nervous system lesions as a direct consequence of a lesion or by disease of the portions of the nervous system that normally signal pain. The spinal nerve ligation (SNL) model in rats that reflect some components of clinical pain have played a crucial role in the understanding of neuropathic pain. To investigate the direct effects of gabapentin on differential gene expression in cultured dorsal root ganglion (DRG) cells of SNL model rats, we performed a differential display reverse transcription-polymerase chain reaction analysis with random priming approach using annealing control primer. Genes encoding metallothionein 1a, transforming growth factor-${\beta}1$ and palmitoyl-protein thioesterase-2 were up-regulated in gabapentin-treated DRG cells of SNL model rats. The functional roles of these differentially expressed genes were previously suggested as neuroprotective genes. Further study of these genes is expected to reveal potential targets of gabapentin.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.6
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• pp.307-314
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• 2008

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Among the many issues for prosthesis development, stimulation encoding strategy is one of the most essential electrophysiological issues. The more we understand the retinal circuitry how it encodes and processes visual information, the greater it could help decide stimulation encoding strategy for retinal prosthesis. Therefore, we examined how retinal ganglion cells (RGCs) in in-vitro retinal preparation act together to encode a visual scene with multielectrode array (MEA). Simultaneous recording of many RGCs with MEA showed that nearby neurons often fired synchronously, with spike delays mostly within 1 ms range. This synchronized firing - narrow correlation - was blocked by gap junction blocker, heptanol, but not by glutamatergic synapse blocker, kynurenic acid. By tracking down all the RGC pairs which showed narrow correlation, we could harvest 40 functional connectivity maps of RGCs which showed the cell cluster firing together. We suggest that finding functional connectivity map would be useful in stimulation encoding strategy for the retinal prosthesis since stimulating the cluster of RGCs would be more efficient than separately stimulating each individual RGC.