• Herbal Formula Science
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• v.7 no.1
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• pp.143-151
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• 1999

To evaluate the neurotoxic effect of oxygen radicals in cultured mouse spinal dorsal root ganglion(DRG) neurons, cytotoxicity was determined by MTT assay after cultured DRG neurons were grown in the media containing various concentrations of glucose oxidase(GO). In addition, neuroprotective effect of herb extract, Epimedium Koreanum Nakai was examined by MTT assay in cultured DRG neurons. Cell viability of cultured DRG neurons was remarkably decreased by GO in dose- and time-dependent manner, and Epimedium Koreanum Nakai protected remarkably GO-induced neurotoxicity in these cultures. From the above results, it is suggested that oxygen radicals is toxic in cultured mouse DRG neurons, and herb extracts such as Epimedium Koreanum Nakai are effective in prevention of the neurotoxicity induced by oxygen radicals in cultured mouse DRG neurons.

• International Journal of Oral Biology
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• v.31 no.2
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• pp.45-51
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• 2006

R-type($Ca_v2.3$) calcium channel contributes to pain sensation in peripheral sensory neurons. Six isoforms of $Ca_v2.3$ that result from combinations of presence or deletion of three inserts(insert I and insert in the II-III loop, and insert III in N-terminal regions) have been demonstrated to be present in different mammalian tissues. However, the molecular basis of $Ca_v2.3$ in trigeminal ganglion(TG) neurons is not known. In the present study, we determined which isoforms of $Ca_v2.3$ are expressed in rat TG neurons using the RT-PCR analysis. Whole tissue RT-PCR analyses revealed that only two isoforms, $Ca_v2.3a$ and $Ca_v2.3e$, were present in TG neurons. From single-cell RT-PCR, we found that $Ca_v2.3e$ rather than $Ca_v2.3a$ was the major isoform expressed in TG neurons, and $Ca_v2.3e$ was preferentially detected in small-sized neurons that express nociceptive marker, transient receptor potential vanilloid 1(TRPV1). Our results suggest that $Ca_v2.3e$ in trigeminal neurons may be a potential target for the pain treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.331-341
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• 2018

The aim of the present study was to examine the effects of preemptive analgesia on the development of trigeminal neuropathic pain. For this purpose, mechanical allodynia was evaluated in male Sprague-Dawley rats using chronic constriction injury of the infraorbital nerve (CCI-ION) and perineural application of 2% QX-314 to the infraorbital nerve. CCI-ION produced severe mechanical allodynia, which was maintained until postoperative day (POD) 30. An immediate single application of 2% QX-314 to the infraorbital nerve following CCI-ION significantly reduced neuropathic mechanical allodynia. Immediate double application of QX-314 produced a greater attenuation of mechanical allodynia than a single application of QX-314. Immediate double application of 2% QX-314 reduced the CCI-ION-induced upregulation of GFAP and p-p38 expression in the trigeminal ganglion. The upregulated p-p38 expression was co-localized with NeuN, a neuronal cell marker. We also investigated the role of voltage-gated sodium channels (Navs) in the antinociception produced by preemptive application of QX-314 through analysis of the changes in Nav expression in the trigeminal ganglion following CCI-ION. Preemptive application of QX-314 significantly reduced the upregulation of Nav1.3, 1.7, and 1.9 produced by CCI-ION. These results suggest that long-lasting blockade of the transmission of pain signaling inhibits the development of neuropathic pain through the regulation of Nav isoform expression in the trigeminal ganglion. Importantly, these results provide a potential preemptive therapeutic strategy for the treatment of neuropathic pain after nerve injury.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.6
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• pp.541-553
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• 2023

Retinal prostheses have shown some clinical success in restoring vision in patients with retinitis pigmentosa. However, the post-implantation visual acuity does not exceed that of legal blindness. The reason for the poor visual acuity might be that (1) degenerate retinal ganglion cells (RGCs) are less responsive to electrical stimulation than normal RGCs, and (2) electrically-evoked RGC spikes show a more widespread not focal response. The single-biphasic pulse electrical stimulation, commonly used in artificial vision, has limitations in addressing these issues. In this study, we propose the benefit of multiple consecutive-biphasic pulse stimulation. We used C57BL/6J mice and C3H/HeJ (rd1) mice for the normal retina and retinal degeneration model. An 8 × 8 multi-electrode array was used to record electrically-evoked RGC spikes. We compared RGC responses when increasing the amplitude of a single biphasic pulse versus increasing the number of consecutive biphasic pulses at the same stimulus charge. Increasing the amplitude of a single biphasic pulse induced more RGC spike firing while the spatial resolution of RGC populations decreased. For multiple consecutive-biphasic pulse stimulation, RGC firing increased as the number of pulses increased, and the spatial resolution of RGC populations was well preserved even up to 5 pulses. Multiple consecutive-biphasic pulse stimulation using two or three pulses in degenerate retinas induced as much RGC spike firing as in normal retinas. These findings suggest that the newly proposed multiple consecutive-biphasic pulse stimulation can improve the visual acuity in prosthesis-implanted patients.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.56 no.12
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• pp.749-753
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• 2013

Basically stem cells have characteristics of multi-potency, differentiation into multiple tissue types, and self-renew through proliferation. Recent advances in stem cell biology can make identifying the stem-cell like cells in various mammalian tissues. Stem cells in various tissues can restore damaged tissue. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the tympanic membrane, vestibular system, spiral ganglion, and partly in the organ of Corti. The presence of stem cells in the ear raises the possibilities for the regeneration of the tympanic membrane & inner ear hair cells & neurons. But the gradual loss of stem cells postnatally in the organ of Corti may correlate with the loss of regenerative capacity and limited hearing restoration. Future strategies using endogenous stem cells in the ear can be the another treatment modality for the patients with intractable inner ear diseases.

• Journal of the korean veterinary medical association
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• v.5 no.1
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• pp.6-7
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• 1961

A 50 days old chick was examined for a diagnosis of tumor occured on the back. Chick was abnormal as early as days old, by having a small tumor, with symptom of anorexja and general depression. A the time of death, tumor had growned as large as avoid ches

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.26-26
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• 2001

Inactivation of N-type calcium current has been reported to be both voltage dependent and Ca$\^$2＋/ dependent. We have investigated the effects of Ba$\^$2＋/ and Ca$\^$2＋/ on N-channel inactivation in rat superior cervical ganglion neurons using the whole cell configuration of patch clamp technique. Inactivation was larger in Ca$\^$2＋/ than in Ba$\^$2＋/ even with 20 mM BAPTA.(omitted)

• 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.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.719-726
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• 1997

Dorsal root ganglion(DRG) cells are primary sensory neurons which contain some biologically active neuropeptides which play a role as neurotransmitters or neuromodulators. This study was performed to observe normal distribution of calcitonin gene-related peptide (CGRP) and substance P (SP) immunoreactive cells and colocalization of CGRP and SP in a single DRG cell of the lumbar DRGs($L_1{\sim}L_6$) in the Wistar Kyoto(WKY) rat by immunohistochemistry. About 55.8% of DRG cells contained CGRP-immunoreactivity, while about 12.7% of DRG cells showed SP-immunoreactivity. There was no significant difference in percentage of each neuropeptied-immunoreactive cells between each neuropeptide-immunoreactive cells between each levels of DRGs ($L_1{\sim}L_6$) (p>0.01). In size distribution, CGRP-immunoreactive cells were identified below $1,500{\mu}m^2$; SP-immunoreactive cells below $600{\mu}m^2$. In serial sections, about 86.7% of the SP immunoreactive cells contained CGRP immunoreactivity.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.108-115
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• 2012

The hyperpolarization-activated current ($I_h$) is an inward cation current activated by hyperpolarization of the membrane potential and plays a role as an important modulator of action potential firing frequency in many excitable cells. In the present study we investigated the effects of extracellular divalent cations on $I_h$ in dorsal root ganglion (DRG) neurons using whole-cell voltage clamp technique. $I_h$ was slightly increased in $Ca^{2+}$-free bath solution. BAPTA-AM did not change the amplitudes of $I_h$. Amplitudes of $I_h$ were decreased by $Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$ dose-dependently and voltage-independently. Inhibition magnitudes of $I_h$ by external divalent cations were partly reversed by the concomitant increase of extracellular $K^+$ concentration. Reversal potential of $I_h$ was significantly shifted by $Ba^{2+}$ and $V_{1/2}$ was significantly affected by the changes of extracellular $Ca^{2+}$ concentrations. These results suggest that $I_h$ is inhibited by extracellular divalent cations ($Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$) by interfering ion influxes in cultured rat DRG neurons.