• Journal of Korean Neurosurgical Society
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• 제29권11호
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• pp.1429-1436
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• 2000

Objectives : This study was performed in cultured rat hippocampal neurons to investigate the acute electrophysiological features of ionotropic glutamate receptors which act as a major excitatory neurotransmitter in mammalian brain. Method : Glutamate receptor agonists were applied into the bath solution embedding in whole-cell patch-clamp recording of single hippocampal neuron. Results : In voltage-clamped at -60mV and the presence of 1mmol $Mg^{2+}$, extracellulary applied NMDA did not induce any inward current. Both the elimination of $Mg^{2+}$ and addition of glycine in bath, however, elicited a NMDAinduced inward current. $Mg^{2+}$ block current was increased gradually in more negative potentials from -30mV, showing a negative slope in I-V plot with $Mg^{2+}$. Glutamate-induced current represented an outward rectification. A non-NMDA receptor component occupied about 40% of glutamate-induced current in the voltage range of -80mV to +60mV. Conclusion : Present study suggests that glutamate activates acutely the non-NMDA receptors which induces an inward current in the level of resting membrane potential. This makes the membrane potential increase and can activate the NMDA receptors that permit calcium influx against $Mg^{2+}$ block. At the depolarized state of neuron, there may be recovery mechanisms of membrane potential to repolarize irrespective of voltage-dependent potassium channels in the hippocampal neurons.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2226-2229
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• 2003

A new method is presented to construct a classifier. This was accomplished by combining a generalized regression neural network (GRNN) and a genetic algorithm (GA). The classifier constructed in this way is referred to as a GA-GRNN. The GA played a role of controlling training factors simultaneously. In GA optimization, neuron spreads were represented in a chromosome. The proposed optimization method was applied to a data set, consisted of 4 different promoter sequences. The training and test data were composed of 115 and 58 sequence patterns, respectively. The range of neuron spreads was experimentally varied from 0.4 to 1.4 with an increment of 0.1. The GA-GRNN was compared to a conventional GRNN. The classifier performance was investigated in terms of the classification sensitivity and prediction accuracy. The GA-GRNN significantly improved the total classification sensitivity compared to the conventional GRNN. Also, the GA-GRNN demonstrated an improvement of about 10.1% in the total prediction accuracy. As a result, the proposed GA-GRNN illustrated improved classification sensitivity and prediction accuracy over the conventional GRNN.

• 동의생리병리학회지
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• 제19권1호
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• pp.75-80
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• 2005

The purpose of study is that we will observe the change of c-fos and CGRP with the immunohistochemistry method and then we will study the effect of microcurrent stimulation following the frequency after inducing pain to rats with capsaicin. The experimental groups were divided by microcurrent application and pain induce. Normal control groups is used in experiment I, the group which we induce pain is used in experiment II, the application group which we induce pain and then the high frequency microcurrent stimulation is used in experiment III, the application group which we induce pain and then the low frequency microcurrent stimulation is used in experiment IV. c-fos was strongly expressed after pain induced 2 hours and positive neurons were decreased from 2 hours. At 7 days, positive neuron recovers to normal range, But c-fos positive neuron of microcurrent stimulation group were decreased from 2 hours. CGRP was strongly expressed after pain induced 24 hours, and positive neurons were decreased from 7 days. These results suggests that microcurrent stimulation therapy effect to control pain according to expression of c-fos and CGRP examined by immunohistochemistry. Also high frequency microcurrent stimulation is more effective than low frequency microcurrent stimulation for controling the pain.

• Biomolecules & Therapeutics
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• 제1권1호
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• pp.37-43
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• 1993

Electrical or chemical stimulation of many areas in the brainstem modulates activity of dorsal horn neurons (DHN). This is known to be mediated by a population of bulbospinal neurons. Yet, little is known about responses of DHNs to stimulation of the caudal ventrolateral medulla (CVLM). Thus, the purpose of the present study is to see if there is any change in activity of DHNs when CVLM is stimulated electrically. Thirty-one DHNs were recorded from dorsal horn of the spinal cord. Fourteen DHNs (45%) were classified as wide dynamic range neurons and 9 (19%) were high threshold cells, and 4 (13%) and 4 (13%) were deep and low threshold neurons, respectively. Among 31 neurons tested for responses to stimulation of CVLM, 21 DHNs (68%) were inhibited by the electrical stimulation of CVLM ($200{\mu}A,\;100{\mu}s$ duration, 100 Hz), and 9 cells (39%) did not show any change in neuronal activity. One neuron was excited by the stimulation. The electrical stimulation of CVLM not only inhibited spontaneous activity of DHNs but also inhibited evoked responses of DHNs to somatic stimulation in the receptive field. These data suggest that CVLM is one of the pain-modulatory areas that control transmission of ascending information of noxious input to the brain from the spinal cord.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.174-179
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• 2014

Since in vitro neural recording and imaging applications based on a surface plasmon resonance (SPR) technique have expanded dramatically in recent years, cytotoxicity assessment to ensure the biosafety and biocompatibility for those applications is crucial. Here, we report the cytotoxicity of the SPR substrate incorporating a flint glass whose refractive index is larger than that of a conventional crown glass. A high refractive index glass substrate is essential in neural signal detection due to the advantages such as high sensitivity and wide dynamic range. From experimental data using primary hippocampal neurons, it is found that a lead-based flint glass is not appropriate as a neural recording template although the neuron cells are not directly attached to the toxic glass. We also demonstrate that the adhesion layer between the glass substrate and the gold film plays an important role in achieving the substrate stability and the cell viability.

• The Korean Journal of Physiology and Pharmacology
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• 제7권5호
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• pp.251-254
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• 2003

The present study was designed to examine whether the co-application of morphine with $Ca^{2+}$ channel antagonist $(Mn^{2+},\;verapamil)$, N-methyl-D-aspartate (NMDA) receptor antagonist (2-amino-5-phosphonopentanoic acid$[AP_5]$, $Mg^{2+}$) or protein kinase C inhibitor (H-7) causes the potentiation of morphine-induced antinociceptive action by using an in vivo electrophysiological technique. A single iontophoretic application of morphine or an antagonist alone induced weak inhibition of wide dynamic range (WDR) cell responses to iontophoretically applied NMDA and C-fiber stimulation. Although there was a little difference in the potentiating effects, the antinociceptive action of morphine was potentiated when morphine was iontophoretically applied together with $Mn^{2+}$, verapamil, $AP_5$, $Mg^{2+}$ or H-7. However, the potentiating action between morphine and each antagonist was not apparent, when the antinociceptive action evoked by morphine or the antagonist alone was too strong. These results suggest that the potentiating effect can be caused by the interaction between morphine and each antagonist in the spinal dorsal horn.

• The Korean Journal of Physiology and Pharmacology
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• 제4권1호
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• pp.15-24
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• 2000

Although nociceptive informations are thought to be processed via different neural mechanisms depending on the types of stimuli, sufficient data have not been accumulated yet. We performed a series of experiments to elucidate the possible neural mechanisms as to chemical stimuli such as formalin, capsaicin and ATP. Single unit activity of wide dynamic range (WDR) neurons and high threshold cells were recorded extracellularly from the lumbosacral enlargement of cat spinal cord before and after chemical stimulation to its receptive field (RF). Each chemical substance - formalin $(20{\mu}l,\;4%),$ capsaicin (33 mM) or Mg-ATP (5 mM)- was injected intradermally into the RFs and then the changes in the spontaneous activity, mechanical threshold and responses to the peripheral mechanical stimuli were observed. In many cases, intradermal injection of formalin (5/11) and capsaicin (8/11) resulted in increase of the spontaneous activity with a biphasic pattern, whereas ATP (8/8) only showed initial responses. Time courses of the biphasic pattern, especially the late response, differed between formalin and capsaicin experiments. One hour after injection of each chemical (formalin, capsaicin, or ATP), the responses of the dorsal horn neurons to mechanical stimuli increased at large and the RFs were expended, suggesting development of hypersensitization (formalin 6/10, capsaicin 8/11, and ATP 15/19, respectively). These results are suggested that formalin stimulates peripheral nociceptor, local inflammation and involvement of central sensitization, capsaicin induces central sensitization as well as affects the peripheral C-polymodal nociceptors and neurogenic inflammation, and ATP directly stimulates peripheral nociceptors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1601-1604
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• 1997

The most important topic in research of mobile robot is path planning in order to avoid with obstacle. In this study the path planning algorithm using a neural network model is proposed. The inputs of neural network are range data which are acquired form laser range finderm and weights are based on difference with goal direction. The thresholds are made by consdiering the marginal distance between mobile robot and obstacle. Consequently the outputs are obtained by multiplying input and weight. The obtained heading directiion enables the mobile robot to approach the goal, without any collision with obstacles around. The effectiveness of the this method of real-time navigation of a mobile robot is estimated by computer simulation in complex environment.

• Journal of Chest Surgery
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• 제35권12호
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• pp.847-853
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• 2002

저자는 이미 120분간의 역행성 뇌관류를 시행하여 이의 안전성에 대한 결과를 발표한 바 있다. 이번 연구는 neuron-specific enolase와 S100 베타 단백의 혈청 및 소변내 농도와의 관계 및 변화를 관찰하고 소변 검체를 통한 뇌손상 조기 검출 가능성에 대하여 규명하고자 계획하였다. 대상 및 방법: 35 kg 돼지를 이용하여 120분간 역행성 뇌관류를 시행한후, 심폐기 이탈을 시행하고 2시간 동안 생존을 유도하였으며, 시간 변화에 따른 동맥 혈압, 경정맥압, 혈청 및 소변내 neuron-specific enolose (NSE) 및 S100베타 단백치를 측정하였다. 역행성 뇌관류 시행 중 중심정맥압은 20~25 mmHg를 유지하였다. 결과: neuron-specific enolase의 혈청농도(ng/$m\ell$)는 마취 유도 시 0.67$\pm$0.18, 심폐기 가동 직후에 0.53$\pm$0.47, 심폐기 가동 후 20분대에 0.44$\pm$0.27, 역행성 뇌관류 20분대에 0.24$\pm$0.09, 40분대에 0.37$\pm$0.35, 60분대에 0.33$\pm$0.21, 80분대에 0.37$\pm$0.22, 100분대에 0.41$\pm$0.23, 120분대에 0.48\ulcorner0.26, 심폐기 재가동후 30분대에 0.42$\pm$0.29, 60분대에 0.35$\pm$0.32, 심폐기 이탈 후 30분대에 0.42$\pm$0.37, 60분대에 0.47$\pm$0.34, 90분대에 0.47$\pm$0.28, 120분대에 0.57$\pm$0.29 로 나타나 역행성 뇌관류 전후에 유의한 변화 양상을 관찰할 수 없었다(ANOVA, p＞0.05). 요중 농도(ng/$m\ell$) 또한 역행성 뇌관류 전후에 유의한 변화 양상을 관찰할 수 없었다(ANOVA, p＞0.05). 또한 혈중 농도와 요중 농도간의 상관성을 발견할 수 없었다(Pearson correlation, p＞0.05). 동일한 측정 시점에서의 S-100 베타 단백 혈청 농도(ng/$m\ell$)는 0.14$\pm$0.08, 0.15$\pm$0.07, 0.22$\pm$0.15, 0.23$\pm$0.07, 0.28$\pm$0.10, 0.40$\pm$0.05, 0.47$\pm$0.03, 0.49$\pm$0.12, 0.43$\pm$0.11, 0.46$\pm$0.15, 0.62$\pm$0.17, 0.77$\pm$0.21, 0.78$\pm$0.23, 0.77$\pm$0.23, 0.82$\pm$0.33으로 뇌관류를 시행한 이후에서 시행이전에 비해 유의하게 상승하였음을 관찰할 수 있었다(ANOVA, p＜0.05, post hoc test). S-100 베타 단백의 소변내 농도(ng/$m\ell$)는 역행성 뇌관류 기간을 제외하고 동일한 측정시점에서 측정할 수 있었으며, 심폐기 가동전에 비해 재가동 후 측정치가 모두 통계적으로 유의하게 상승하였다(ANOYA, p＜0.05). 혈중 측정치와 요중 측정치는 모두 역행성 뇌관류 후 증가하는 양상을 보였으며 의미 있는 상관성을 발견할 수 있었다(Pearson correlation, p＜0.05). 결론: 뇌손상 여부를 판단하기 위하여 시행한 검사 중 S-100 베타 단백의 혈청 및 소변에서의 수치는 뇌관류 전보다 유의하게 증가하는 양상을 보였으며 두 검체 사이에는 의미 있는 상관관계가 있음을 알 수 있었다. 뇌손상의 조기 지표로서 S-100 베타단백을 활용할 수 있는 기초자료가 되었다고 생각되며, 환자를 대상으로 한 임상 연구를 할 수 있는 토대가 되었다고 사료된다.

• Molecules and Cells
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• 제38권6호
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• pp.535-539
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• 2015

Olfactory stimulation activates multiple signaling cascades in order to mediate activity-driven changes in gene expression that promote neuronal survival. To date, the mechanisms involved in activity-dependent olfactory neuronal survival have yet to be fully elucidated. In the current study, we observed that olfactory sensory stimulation, which caused neuronal activation, promoted activation of the phosphatidylinositol 3'-kinase (PI3K)/Akt pathway and the expression of Bcl-2, which were responsible for olfactory receptor neuron (ORN) survival. We demonstrated that Bcl-2 expression increased after odorant stimulation both in vivo and in vitro. We also showed that odorant stimulation activated Akt, and that Akt activation was completely blocked by incubation with both a PI3K inhibitor (LY294002) and Akt1 small interfering RNA. Moreover, blocking the PI3K/Akt pathway diminished the odorantinduced Bcl-2 expression, as well as the effects on odorant-induced ORN survival. A temporal difference was noted between the activation of Akt1 and the expression of Bcl-2 following odorant stimulation. Blocking the PI3K/Akt pathway did not affect ORN survival in the time range prior to the increase in Bcl-2 expression, implying that these two events, activation of the PI3K pathway and Bcl-2 induction, were tightly connected to promote post-translational ORN survival. Collectively, our results indicated that olfactory activity activated PI3K/Akt, induced Bcl-2, and promoted long term ORN survival as a result.