Effect of Capsaicin and Its Derivative on the Voltage Dependent Ca^2+ Currents in Spinal Dorsal Root and Trigeminal Ganglion Neurons

Oh, Seog Bae,Yoon, Chan Song,Nam, Sang Chae,Park, Kyungpyo,Lee, Jong-Heun,Kim, Joong-Soo Korean Academy of Oral Biology and the UCLA Dental 1997 International Journal of Oral Biology Vol.22 No.4

Capsaicin produces initial irritation followed by insensitivity to noxious stimuli. It can not be easily used in clinical pain control due to its toxic effects. Recently, a capsaicin derivative (KR) was developed to use as an analgesic with fewer toxic effects. However, the mechanism of action and clinical effects of KR are not well understood. In this experiment we tried to explore the cellular mechanisms of the analgesic effect induced by capsaicin and KR in DRG or TG neurons. The DRG and TG neurons were acutely isolated into single neuronal cells from neonatal or adult rats with trypsin treatment and mechanical trituration. Voltage dependent calcium currents were measured with whole-cell patch clamp configuration in small diameter sensory neurons (between 10 μm and 20μm). On the basis of activation threshold, Ca^2+ currents of DRG and TG neurons were classified as LVA (T-type) and HVA I_ca. HVA I_ca were subclassified into L-type and N-type. The amplitude of L-type calcium current was remarkably inhibited by application of 1 μM KR in DRG. The inhibition of calcium current recovered significantly at five minutes after application of KR. In most capsaicin-sensitive neurons in TG, capsaicin irreversibly inhibited voltage dependent calcium currents. Capsaicin and KR-induced inhibition of voltage dependent calcium currents would be expected to reduce neurotransmitter release from both central and peripheral terminals of the sensitive primary sensory neurons. This can be proposed as one possible mechanism for the analgesic and anti-inflammatory effects induced by them.

Nimodipine as a Potential Pharmacological Tool for Characterizing R-Type Calcium Currents

Seog Bae Oh 대한생리학회-대한약리학회 2001 The Korean Journal of Physiology & Pharmacology Vol.5 No.6

<P> Nimopidine, one of dihydropyridine derivatives, has been widely used to pharmacologically identify L-type Ca currents. In this study, it was tested if nimodipine is a selective blocker for L-type Ca currents in sensory neurons and heterologous system. In mouse dorsal root ganglion neurons (DRG), low concentrations of nimodipine (<10μM), mainly targeting L-type Ca currents, blocked high-voltage-activated calcium channel currents by ∼38%. Interestingly, high concentrations of nimodipine (>10μM) further reduced the "residual" currents in DRG neurons from α<SUB>1E</SUB> knock-out mice, after blocking L-, N- and P/Q-type Ca currents with 10μM nimodipine, 1μM ω-conotoxin GVIA and 200 nM ω-agatoxin IVA, indicating inhibitory effects of nimodipine on R-type Ca currents. Nimodipine (>10μM) also produced the inhibition of both low-voltage-activated calcium channel currents in DRG neurons and α<SUB>1B</SUB> and α<SUB>1E</SUB> subunit based Ca channel currents in heterologous system. These results suggest that higher nimodipine (>10μM) is not necessarily selective for L-type Ca currents. While care should be taken in using nimodipine for pharmacologically defining L-type Ca currents from native macroscopic Ca currents, nimodipine (>10μM) could be a useful pharmacological tool for characterizing R-type Ca currents when combined with toxins blocking other types of Ca channels.

Isolation of Medullary Dorsal Horn Neurons and Characteristics of Membrane Currents

Oh, Seog Bae,Park, Kyungpyo,Kim, Seong-Ah,Lee, Jong-Heun,Kim, Joong-Soo Korean Academy of Oral Biology and the UCLA Dental 1998 International Journal of Oral Biology Vol.23 No.3

Medullary dorsal horn (MDH)neurons receive noxious inputs from primary afferent fibers in the orofacial area, integrate modulatory influences from descending and local circuits and send the information to the thalamus and somatosensory cortex. In addition, this region contains many putative neurotransmitters, including excitatory and inhibitory amino acids and peptides. Because of the importance of MDH neurons in orofacial pain transmission, the modulation of activities of these cells is very interesting. In this study, we tried to establish a method for isolating and preparing MDH neurons for the purpose of sutdying the pain modulation mechanism in future, and identify if the acutely isolated cells preserve their electrophysiological activities using patch-clamp and fura-2-based microfluorometry techniques. Transverse slices (400 ㎛) of lower brinstem, 2-3 mm caudal to the obex, from neonatal rats (1-2 weeks old)were sequentially digested with two proteases (pronase 1 mg/ 5 ml, and thermolysin 1 mg/5 ml) at 32℃ for 20 min. The MDH region was then dessected out and mechanically dissociated under a stereomicroscope using a series of fire-polished glass pipettes with a variety of orifice sizes. Single isolated cells were used for the experinemt. This method yields multipolar, bipolar, unipolar, ellipse and pyramidal cells. These cells seem to be marginal cells of lamina I, stalked cells or islet cells in lamina II and pyramidal cells in lamina III, respectively. Fura-2-based microfluorometry showed that the intracellular Ca^2+ concentration ([Ca^2+]_i) increased in response to the membrane depolarization induced by high K^+, and the increase of [Ca^2+]_i was caused by the influx of extracellular Ca^2+, demonstrating the expression of voltage-sensitive calcium channels (VSCC) in MDH neuroms. From whole-cell patch-clamp techniques, voltage-sensitive Na^+and Ca^2+ currents were directly recorded, the results were similar to those studied in in vivo or slice preparations. These facts indicate that electrophysiological activities are well preserved in the acutely isolated neurons, and these cells can be effectively used for biophysical and pharmacological studies, including understanding the pain modulation mechanism mediated by VSCC in the MDH.

스냅샷을 사용하는 다중 레벨 공간 DBMS를 가지는 효율적인 센서 미들웨어 구조 설계

오은석 ( Eun-seog Oh ),김호석 ( Ho-seog Kim ),배해영 ( Hae-young Bae ) 한국정보처리학회 2006 한국정보처리학회 학술대회논문집 Vol.13 No.1

최근 들어, 모든 장소에 컴퓨터가 있고 그것을 누구나 자유롭게 사용할 수 있는 인간 중심 유비쿼터스 환경에 대한 연구가 활발하게 진행되고 있다. 그러나 이러한 컴퓨팅 환경에서의 센서 미들웨어들은 연속적인 스트림 데이터 처리에 대한 막대한 비용을 줄이기 위해서 분석이 끝난 스트림 데이터를 삭제한다. 따라서 사용자의 서비스에 삭제된 스트림 데이터가 요구될 경우, 또는 과거 데이터들에 대한 확률 통계 정보가 요구될 경우, 이에 대한 서비스를 사용자에게 제공할 수 없다. 본 논문에서는 이러한 미들웨어에서의 스트림 데이터 재사용 문제를 해결하기 위해서 스냅샷을 가지는 다중 레벨 공간 DBMS를 기반으로 하는 효율적인 센서 데이터 미들웨어 구조를 설계하였다. 본 시스템은 사용자에게 재사용될 가치가 높은 스트림 데이터들을 다중 레벨 공간 DBMS의 디스크 데이터베이스에서 관리한다. 또한 빈번한 서비스를 가지는 스트림 데이터의 경우 해당 스트림 데이터를 메모리 데이터베이스에 관리함으로서 사용자에게 신속한 서비스를 제공한다. 본 시스템은 기존의 미들웨어에서 지원할 수 없었던 동일한 스트림 데이터에 대한 빈번한 요청, 또는 확률이나 통계 자료와 같은 데이터 서비스 요청 문제들을 해결하였다. 그리고 메인 메모리 데이터베이스에 스냅샷 형태로 저장되는 스트림 데이터의 높은 데이터 재사용성을 유지함으로서, 사용자에게 지속적으로 정확하고 신속한 데이터 서비스를 제공한다.

치수통각 전도에서 삼차신경 척수감각핵의 역할

오석배,김중수,이종흔 대한구강생물학회 1991 International Journal of Oral Biology Vol.15 No.2

In spite of many recent studies, there remains a conflict on the relative contribution of caudal and rostral components of trigeminal sensory nuclei to V brainstem mechanism of orofacial nociception. This study was performed to clarify the properties of neurons in trigeminal sensory nuclei which are responsive to noxious electrical stimuli applied to tooth pulp and the role of caudal and rostral components of trigeminal sensory nuclei on the transmission of orofacial nociceptive information. Adult cats are anesthetized with α-chloralose(60 ㎎/㎏), a pair of electrodes was inserted to anterior digastric muscle to record EMG evoked by noxious electric stimuli to tooth pulp and the animal was fixed to stereotaxic frame. An occipital craniotomy and cervical laminectomy were carried out to allow the introduction by a microdrive of glass-coated tungsten microelectrode for recording the extracellular activity of single units in trigeminal spinal sensory nuclei and then responses of neurons to noxious electrical stimuli applied to tooth were examined. 1. The EMG of anterior digastric muscle was response conducted through Aδ primary afferent from tooth pulp and EMG was not disappeared after trigeminal tractotomy at the level of obex. 2. Neural activities in trigeminal sensory nuclei were recorded at lateral 2.5∼5.5 ㎜ to obex. 1.5∼3.0 ㎜ below the bulbar surface and rostrocaudal 4∼-3 ㎜ obex. 3. Neural activities were not recorded in case that noxious electrical stimuli were applied to cotralateral tooth. 4. In rostral parts, neural activities were recorded at the neurons conducted through Aβ and Aδ primary afferent from ipsilateral tooth. 5. In rostral parts, neural activities were recorded at the neurons conducted through C primary afferent from ipsilateral tooth. From these results, it is assumed that sensation other than pain mediated by Aβ-nerve fiber and sharp pain mediated by Aδ-nerve fiber are transmitted through rostral part of trigeminal sensory nuclei and dull pain mediated by C-nerve fiber is transmitted through caudal part of trigrmianl sensory nuclei.

Fatigue Properties of Copper Foil and the Evolution of Surface Roughness

Oh, Chung-Seog,Bae, Jong-Sung,Lee, Hak-Joo Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.4

The aim of this investigation was to extract the fatigue properties at the designated fatigue life of copper foil and observe the mean stress and stress amplitude effects on both the fatigue life and the corresponding surface morphology. Tensile tests were performed to determine the baseline monotonic material properties of the proportional limit and ultimate tensile strength. Constant amplitude fatigue tests were carried out using a feedback-controlled fatigue testing machine. The mean stress and the stress amplitude were changed to obtain the complete nominal stress-life curves. An atomic force microscope was utilized to observe the relationship between the fatigue damage and the corresponding changes in surface morphology. A Basquin's exponent of-0.071 was obtained through the fatigue tests. An endurance limit of 122 MPa was inferred from a Haigh diagram. The specimen surface became rougher as the number of fatigue cycles increased, and there was a close relationship between the fatigue damage and the surface roughness evolution.

급성 충수염의 천공여부를 예측할 수 있는 판별함수

민석기,이준희,정병욱,오민구,배성한,박동일,안우섭,서정욱 대한대장항문학회 1996 Annals of Coloproctolgy Vol.12 No.1

Fatigue Properties of Copper Foil and the Evolution of Surface Roughness

Chung-Seog Oh,Jong-Sung Bae,Hak-Joo Lee 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.4

The aim of this investigation was to extract the fatigue properties at the designated fatigue life of copper foil and observe the mean stress and stress amplitude effects on both the fatigue life and the corresponding surface morphology Tensile tests were performed to determine the baseline monotonic material properties of the proportional limit and ultimate tensile strength. Constant amplitude fatigue tests were carried out using a feedback-controlled fatigue testing machine. The mean stress and the stress amplitude were changed to obtain the complete nominal stress￢life curves. An atomic force microscope was utilized to observe the relationship between the fatigue damage and the corresponding changes in surface morphology. A Basquin's exponent of-0.071 was obtained through the fatigue tests. An endurance limit of 122 MPa was inferred from a Haigh diagram. The specimen surface became rougher as the number of fatigue cycles increased, and there was a close relationship between the fatigue damage and the surface roughness evolution.

First-Line chemotherapy with capecitabine and gemcitabine for advanced pancreatic cancer and clinical significance of CA19-9

( Byeong Bae Park ),( Joon Oh Park ),( Hyo Rak Lee ),( Hyun Jung Kim ),( Jung Mi Kwon ),( Sung Yong Oh ),( Jee Yun Lee ),( Ki Hyun Kim ),( Jin Seok Ahn ),( Won Seog Kim ),( Chul Won Jung ),( Young Suk 대한내과학회 2005 대한내과학회 추계학술대회 Vol.69 No.10

Which is the most accurate parameter to estimate the pulmonary wedge pressure in critically ill patients?

Woo Hyung Bae,June Hong Kim,Jun Hyuk Oh,Dong Won Lee,Sung Gook Song,Jeong Su Kim,Hyeon Gook Lee,Woo Seog Ko,Yong Hyun Park,Sang Gwon Lee,Kook Jin Chun,Taek Jong Hong,Yung Woo Shin 대한내과학회 2004 대한내과학회 추계학술대회 Vol.2004 No.1