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우준성,한영은,고우현,Joungha Won,박민구,안희영,이창준 한국뇌신경과학회 2019 Experimental Neurobiology Vol.28 No.1
The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 μm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K+ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.
우준성,임선경,천희정,정순영,오수진,최낙원,허은미,이창준 한국뇌신경과학회 2017 Experimental Neurobiology Vol.26 No.3
Brain is a rich environment where neurons and glia interact with neighboring cells as well as extracellular matrix in three-dimensional (3D) space. Astrocytes, which are the most abundant cells in the mammalian brain, reside in 3D space and extend highly branched processes that form microdomains and contact synapses. It has been suggested that astrocytes cultured in 3D might be maintained in a less reactive state as compared to those growing in a traditional, two-dimensional (2D) monolayer culture. However, the functional characterization of the astrocytes in 3D culture has been lacking. Here we cocultured neurons and astrocytes in 3D and examined the morphological, molecular biological, and electrophysiological properties of the 3D-cultured hippocampal astrocytes. In our 3D neuron-astrocyte coculture, astrocytes showed a typical morphology of a small soma with many branches and exhibited a unique membrane property of passive conductance, more closely resembling their native in vivo counterparts. Moreover, we also induced reactive astrocytosis in culture by infecting with high-titer adenovirus to mimic pathophysiological conditions in vivo. Adenoviral infection induced morphological changes in astrocytes, increased passive conductance, and increased GABA content as well as tonic GABA release, which are characteristics of reactive gliosis. Together, our study presents a powerful in vitro model resembling both physiological and pathophysiological conditions in vivo, and thereby provides a versatile experimental tool for studying various neurological diseases that accompany reactive astrocytes.
Isoliquiritigenin, a Chalcone Compound, Enhances Spontaneous Inhibitory Postsynaptic Response
우준성,이창준,조승목 한국뇌신경과학회 2014 Experimental Neurobiology Vol.23 No.2
Isoliquiritigenin (ILTG) is a chalcone compound and shows various pharmacological properties, including antioxidant and anti-inflammatory activities. In recent study, we have reported a novel role of ILTG in sleep through a positive allosteric modulation ofgamma-aminobutyric acid type A (GABAA)-benzodiazepine (BZD) receptors. However, the effect of ILTG in GABAAR-mediatedsynaptic response in brain has not been tested yet. Here we report that ILTG significantly prolonged the decay of spontaneousinhibitory postsynaptic currents (sIPSCs) mediated by GABAAR in mouse hippocampal CA1 pyramidal neurons without affectingamplitude and frequency of sIPSCs. This enhancement was fully inhibited by flumazenil (FLU), a specific GABAA-BZD receptorantagonist. These results suggest a potential role of ILTG as a modulator of GABAergic synaptic transmission.
우준성,양혜진,Changdev G. Gadhe,Ae Nim Pae,조승목,윤민석,이창준 한국뇌신경과학회 2019 Experimental Neurobiology Vol.28 No.5
3-Carene, a bicyclic monoterpene, is one of the major components of the pine tree essential oils. It has been reported that, in addition to its known properties as a phytoncide, 3-carene has anti-inflammatory, antimicrobial, and anxiolytic effects. We have previously demonstrated that α-pinene, the major component of pine tree, has a hypnotic effect through GABAA-benzodiazepine (BZD) receptors. However, a hypnotic effect of 3-carene has not been studied yet. Here, we report that oral administration of 3-carene increases the sleep duration and reduces sleep latency in pentobarbital-induced sleep test. 3-Carene potentiates the GABAA receptor-mediated synaptic responses by prolonging the decay time constant of inhibitory synaptic responses. These enhancing effects of 3-carene are reproduced by zolpidem, a modulator for GABAA-BZD receptor, and fully inhibited by flumazenil, an antagonist for GABAA-BZD receptor. The molecular docking of 3-carene to the BZD site of GABAA protein structure, suggests that 3-carene binds to the BZD site of α1 and ϒ2 subunits of GABAA-BZD receptor. These results indicate that, similar to α-pinene, 3-carene shows a sleep-enhancing effect by acting as a positive modulator for GABAA-BZD receptor.
우준성,이창준 한국뇌신경과학회 2020 Experimental Neurobiology Vol.29 No.2
Sleep is indispensable for living animals to live and maintain a normal life. Due to the growing number of people suffering from sleep disorders such as insomnia, there have been increasing interests in environmentally friendly therapeutic approaches for sleep disorders to avoid any side effects of pharmacological treatment using synthetic hypnotics. It has been widely accepted that the various beneficial effects of forest, such as relieving stress and anxiety and enhancing immune system function, are caused by plant-derived products, also known as phytoncide. Recently, it has been reported that the sleep-enhancing effects of phytoncide are derived from pine trees such as (-)-α-pinene and 3-carene. These are the major constituents of pine tree that potentiate the inhibitory synaptic responses by acting as a positive modulator for GABAA-BZD receptor. In this review, we discuss the effects of phytoncide on sleep and review the latest approaches of sleep-related behavioral assay, electrophysiological recording, and molecular modeling technique.
우준성(Jun Seong Woo),전갑진(Kab-Jin Jun),박태원(Tae Won Park),박중경(Joong Kyung Park),황재철(JaeChul Hwang),조동협(donghyeob.cho),류제형(JeHyoung Ryu),김혁(Hyuk Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
When compared with a gear and chain, a timing belt is an efficient element to transfer object in the system. The timing belt can move objects and the system can be operated quietly. Moreover, users can control the translation of the object precisely by the step motors and electronic control devices. But the failure of the timing belt can cause economical loss and even injure of operator. Although the design standard has been offered by the suppliers of the timing belt, users can’t predict the life of the timing belt in operating environment. We made the computer program with the life prediction method of the timing belt, and it can help the users to choose the suitable timing belt in the system.
우준성(Junseong Woo),배진욱(Jinwook Bae),임종현(Jonghyun Yim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Many countries have established their own regulations and classifications to protect pedestrians. Certification test of pedestrian protection is important to get a selling permission of vehicle. This result is composed of head injury (HIC_15), acceleration and bending angle of lower leg, femur force and bending moment of upper leg. In this paper, improved section shapes and materials for lower leg impact was researched by CAE. The stiffness of a bumper foam and a LBS(lower bumper) affects a tibia acceleration, and the angle between hood edge and bumper affects a bending angle. Lower leg injury can be reduced by proper composition of the stiffness and angle. Additionally, we suggested an improved design for TIC test as well as pedestrian protection.
공기 현가장치를 장착한 화물차량의 진동측정 및 한국형 공기 현가장치 모듈 개발
우준성(Woo, Jun-Seong),전용호(Jeon, Yong-Ho),정성필(Jung, Sung-Pil),박태원(Park, Tae-Won),권순기(Kwon, Soon-Ki) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.12
A leaf spring suspension has been widely used since it can carry big load and its simplicity. But one major drawback is the poor ride performance because of the friction in the system and the high stiffness coefficient. To overcome these, an air spring suspension can be used. The air spring suspension system can improve the ride of the heavy vehicle significantly and also it can adjust the height to the loading and unloading. The road tests for the truck with the leaf spring suspension and air spring suspension are performed to compare the ride quality of the two systems. To develop the air spring suspension system tailored to the target truck, chassis development procedure using CAE has been applied.