• Advances in Traditional Medicine
• /
• v.1 no.1
• /
• pp.64-70
• /
• 2000

Effects of Rhizoma gastrodiae on glucose oxidase-induced neurotoxicity was investigated in cultured newborn mouse spinal dorsal root ganglion(DRG) neurons that were treated in the media with or without glucose oxidase. In addition, the protective effect of Rhizoma gastrodiae extract against glucose oxidase-induced neurotoxicity was examined. Cytotoxic values were expressed as a percentage of number of living cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In this paper, exposure of neurons to glucose oxidase resulted in a significant call death in a dose- and time-dependent manners in DRG neuron cultures. The decrease in cell viability induced by the glucose oxidase was blocked by Rhizoma gastrodiae extract. These results indicate that the neuroprotective effect of Rhizoma gastrodiae extract against glucose oxidase-induced neurotoxicity may result from a prevention or attenuation of oxidative damage induced by glucose oxidase.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.5
• /
• pp.1305-1308
• /
• 2003

To evaluate the neurotoxicity of reactive oxygen species (ROS) in cultured cultured spinal dorsal root(DRG) neurons derived from neonatal mouse, Cytotoxicity was measured by MTS assay after cultured cells were grown for 3 hours in the media containing 1～60 μM hydrogen peroxide (H₂O₂). In addition the neuroprotective effect of Salviae Miltiorrhzae Radix (SMR) was measured in these cultrures. Cell viability was positively decreased in a dose- and time-dependent manner after exposure of cultured mouse DRG neurons to 30 tt M H202 for 3 hours. In the neuroprotective effect of SMR on H₂O₂-mediated toxicity, SMR prevented the H₂O₂-induced neurotoxicity in these cultures. From these results. it suggests that H₂0₂ is toxic in cultured mouse spinal motor neurons and selective herb extract such as Uncariae Ramulus Cum Uncis is effective in prevetion of the neurotoxicity induced by H₂O₂.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1981.05a
• /
• pp.37.2-38
• /
• 1981

Recently the efficacy of all ear drops in perforated tympanic membranes has been questioned and the safety of using the drugs intratympanically has been challanged. Many drugs not normally ototoxic when given systemically become ototoxic when administered via the middle ear. According to Stupp and others (1973) among neomycin, polymyxin-G, gentamycin, erythr omycin, tetracycline and penicillin, only penicillin was found to be free of toxic effects. The ototoxic antibiotics probably reach the inner ear by permeating the round window membrane, into the perilymph and then through Reissner's membrane to the endolymph. The main pathological changes are degeneration of stria vascularis, degeneration of sensory epithelia and degeneration of ganglion cells. We report with reference, a case of profound sensorineural deafness following the application of Terramycin powder intratympanically, in a 63 year old woman.

• BMB Reports
• /
• v.50 no.2
• /
• pp.60-70
• /
• 2017

Glaucoma is characterized by a slow and progressive degeneration of the optic nerve, including retinal ganglion cell (RGC) axons in the optic nerve head (ONH), leading to visual impairment. Despite its high prevalence, the biological basis of glaucoma pathogenesis still is not yet fully understood, and the factors contributing to its progression are currently not well characterized. Intraocular pressure (IOP) is the only modifiable risk factor, and reduction of IOP is the standard treatment for glaucoma. However, lowering IOP itself is not always effective for preserving visual function in patients with primary open-angle glaucoma. The second messenger cyclic adenosine 3',5'-monophosphate (cAMP) regulates numerous biological processes in the central nervous system including the retina and the optic nerve. Although recent studies revealed that cAMP generated by adenylyl cyclases (ACs) is important in regulating aqueous humor dynamics in ocular tissues, such as the ciliary body and trabecular meshwork, as well as cell death and growth in the retina and optic nerve, the functional role and significance of cAMP in glaucoma remain to be elucidated. In this review, we will discuss the functional role of cAMP in aqueous humor dynamics and IOP regulation, and review the current medications, which are related to the cAMP signaling pathway, for glaucoma treatment. Also, we will further focus on cAMP signaling in RGC growth and regeneration by soluble AC as well as ONH astrocytes by transmembrane ACs to understand its potential role in the pathogenesis of glaucoma neurodegeneration.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.1
• /
• pp.25-30
• /
• 2012

Under some pathological conditions as bile flow obstruction or liver diseases with the enterohepatic circulation being disrupted, regurgitation of bile acids into the systemic circulation occurs and the plasma level of bile acids increases. Bile acids in circulation may affect the nervous system. We examined this possibility by studying the effects of bile acids on gating of neuronal (N)-type $Ca^{2+}$ channel that is essential for neurotransmitter release at synapses of the peripheral and central nervous system. N-type $Ca^{2+}$ channel currents were recorded from bullfrog sympathetic neuron under a cell-attached mode using 100 mM $Ba^{2+}$ as a charge carrier. Cholic acid (CA, $10^{-6}M$) that is relatively hydrophilic thus less cytotoxic was included in the pipette solution. CA suppressed the open probability of N-type $Ca^{2+}$ channel, which appeared to be due to an increase in (no activity) sweeps. For example, the proportion of sweep in the presence of CA was ~40% at +40 mV as compared with ~8% in the control recorded without CA. Other single channel properties including slope conductance, single channel current amplitude, open and shut times were not significantly affected by CA being present. The results suggest that CA could modulate N-type $Ca^{2+}$ channel gating at a concentration as low as $10^{-6}M$. Bile acids have been shown to activate nonselective cation conductance and depolarize the cell membrane. Under pathological conditions with increased circulating bile acids, CA suppression of N-type $Ca^{2+}$ channel function may be beneficial against overexcitation of the synapses.

• Applied Microscopy
• /
• v.22 no.1
• /
• pp.79-88
• /
• 1992

In order to identify the effects of the kainic acid in the retina kainic acid (120 nmol/$5{\mu}l$) were injected through the pars plana of the ciliary body into the duck eye ball at 7th day after hatching. The animals were sacrificed by decapitation on the 1st, 4th and 10th day after injection of the kainic acid. The specimen was processed for the light and electron microscopes respectively. The results obtained were as followings 1. The inner nuclear, inner plexiform and ganglion cell layers of the retina showed marked changes in all of the groups. 2. The cells in the inner nuclear layer showed marked degenerative changes of the organelles including the pyknoses and destruction of the nucleus on the 1st day after injection. These destructive changes of the cells were progressively disappeared until the 10th day after injection. 3. After injection of the kainic acid the neurites of the inner plexiform layer were swollen at the first, and thereafter those changes were gradually disappeared until the 10th day. 4. In the ganglion cell defected by the kinic acid, the enlargement and segmentation of the endoplasmic reticulum and pyknosis of the nucleus were-observed in all the groups, although the lipid droplets were only shown in the 4th day. From the above results, the evidence suggests that kainic acid gives to the toxic effect on the nuurons of the retina with exception of the photoreceptors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.448-451
• /
• 2018

The purpose of this study was to investigate the developmental process of myelination by neuron and Schwann cell cultures and the development of demyelination by herpes simplex virus-1 infection by electron microscopy and molecular biological analysis. The dorsal root ganglion (DRG) was isolated from the mouse embryo and Schwann cells and neuronal cells were cultured in vitro. Neuronal cells treated with mitotic inhibitors and purified Schwann cells were co-cultured together to induce myelination. The herpes simplex virus-1 was infected with the co-cultured cells, and the demyelination was induced. The myelin protein zero (MPZ) antibody, which means the presence of myelin formation, was used and electron microscopy was used to observe the development of myelin and dehydration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.528-532
• /
• 2019

The dorsal root ganglion (DRG) was isolated from mouse embryos and Schwann cells and neuronal cells were cultured in vitro. The neurons and Schwann cells were cultured separately and the two kinds of cells were cultured together for three weeks. Generation of myelination was confirmed by transmission electron microscope and confocal microscope using a myelinaion protein, myelin protein zero (MPZ) antibody. The sindbis virus was infected for three days in the myelinated culture cells and then demyelination was carried out. The process of demyelination was also confirmed by transmission electron microscopy and confocal microscopy using myelin protein zero (MPZ) antibody. The study was supported by a Basic Research Program through the National Research Foundation (NRF) funded by the Ministry of Science and Technology, ICT and Future Plans (NRF-2016R1A2B4016552 and 2017R1A2B3005753).

• Progress in Medical Physics
• /
• v.14 no.4
• /
• pp.211-217
• /
• 2003

The Principal component analysis (PCA) is a well-known data analysis method that is useful in linear feature extraction and data compression. The PCA is a linear transformation that applies an orthogonal rotation to the original data, so as to maximize the retained variance. PCA is a classical technique for obtaining an optimal overall mapping of linearly dependent patterns of correlation between variables (e.g. neurons). PCA provides, in the mean-squared error sense, an optimal linear mapping of the signals which are spread across a group of variables. These signals are concentrated into the first few components, while the noise, i.e. variance which is uncorrelated across variables, is sequestered in the remaining components. PCA has been used extensively to resolve temporal patterns in neurophysiological recordings. Because the retinal signal is stochastic process, PCA can be used to identify the retinal spikes. With excised rabbit eye, retina was isolated. A piece of retina was attached with the ganglion cell side to the surface of the microelectrode array (MEA). The MEA consisted of glass plate with 60 substrate integrated and insulated golden connection lanes terminating in an 8${\times}$8 array (spacing 200 $\mu$m, electrode diameter 30 $\mu$m) in the center of the plate. The MEA 60 system was used for the recording of retinal ganglion cell activity. The action potentials of each channel were sorted by off­line analysis tool. Spikes were detected with a threshold criterion and sorted according to their principal component composition. The first (PC1) and second principal component values (PC2) were calculated using all the waveforms of the each channel and all n time points in the waveform, where several clusters could be separated clearly in two dimension. We verified that PCA-based waveform detection was effective as an initial approach for spike sorting method.

• International Journal of Oral Biology
• /
• v.38 no.1
• /
• pp.13-19
• /
• 2013

Various voltage-gated $K^+$ currents were recently described in dorsal root ganglion (DRG) neurons. However, the characterization and diversity of voltage-gated $K^+$ currents have not been well studied in trigeminal root ganglion (TRG) neurons, which are similar to the DRG neurons in terms of physiological roles and anatomy. This study was aimed to investigate the characteristics and diversity of voltage-gated $K^+$ currents in acutely isolated TRG neurons of rat using whole cell patch clamp techniques. The first type (type I) had a rapid, transient outward current ($I_A$) with the largest current size having a slow inactivation rate and a sustained delayed rectifier outward current ($I_K$) that was small in size having a fast inactivation rate. The $I_A$ currents of this type were mostly blocked by TEA and 4-AP, K channel blockers whereas the $I_K$ current was inhibited by TEA but not by 4-AP. The second type had a large $I_A$ current with a slow inactivation rate and a medium size-sustained delayed $I_K$ current with a slow inactivation rate. In this second type (type II), the sensitivities of the $I_A$ or $I_K$ current by TEA and 4-AP were similar to those of the type I. The third type (type III) had a medium sized $I_A$ current with a fast inactivation rate and a large sustained $I_K$ current with the slow inactivation rate. In type III current, TEA decreased both $I_A$ and $I_K$ but 4-AP only blocked $I_A$ current. The fourth type (type IV) had a smallest $I_A$ with a fast inactivation rate and a large $I_K$ current with a slow inactivation rate. TEA or 4-AP similarly decreased the $I_A$ but the $I_K$ was only blocked by 4-AP. These findings suggest that at least four different voltage-gated $K^+$ currents in biophysical and pharmacological properties exist in the TRG neurons of rats.