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71.
Muscimol Directly Activates the TREK-2 Channel Expressed in GABAergic Neurons through Its N-Terminus
Eun-Jin Kim Oh-Sang Kwon Chang-Gi Hur Marie Merci Nyiramana Dong-Kun Lee Seong-Geun Hong Jaehee Han Dawon Kang 《International journal of molecular sciences》2021,22(17)
The two-pore domain K+ (K2P) channel, which is involved in setting the resting membrane potential in neurons, is an essential target for receptor agonists. Activation of the γ-aminobutyric acid (GABA) receptors (GABAAR and GABABR) reduces cellular excitability through Cl- influx and K+ efflux in neurons. Relatively little is known about the link between GABAAR and the K+ channel. The present study was performed to identify the effect of GABAR agonists on K2P channel expression and activity in the neuroblastic B35 cells that maintain glutamic acid decarboxylase (GAD) activity and express GABA. TASK and TREK/TRAAK mRNA were expressed in B35 cells with a high level of TREK-2 and TRAAK. In addition, TREK/TRAAK proteins were detected in the GABAergic neurons obtained from GABA transgenic mice. Furthermore, TREK-2 mRNA and protein expression levels were markedly upregulated in B35 cells by GABAAR and GABABR agonists. In particular, muscimol, a GABAAR agonist, significantly increased TREK-2 expression and activity, but the effect was reduced in the presence of the GABAAR antagonist bicuculine or TREK-2 inhibitor norfluoxetine. In the whole-cell and single-channel patch configurations, muscimol increased TREK-2 activity, but the muscimol effect disappeared in the N-terminal deletion mutant. These results indicate that muscimol directly induces TREK-2 activation through the N-terminus and suggest that muscimol can reduce cellular excitability by activating the TREK-2 channel and by inducing Cl- influx in GABAergic neurons. 相似文献
72.
Hur CG Choe C Kim GT Cho SK Park JY Hong SG Han J Kang D 《Reproduction (Cambridge, England)》2009,137(2):237-244
Two-pore domain K(+) (K(2P)) channels that help set the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. However, the expression of K(2P) channels has not yet been reported in bovine germ cells. In this study, we demonstrate for the first time that K(2P) channels are expressed in the reproductive organs and germ cells of Korean cattle. RT-PCR data showed that members of the K(2P) channel family, specifically KCNK3, KCNK9, KCNK2, KCNK10, and KCNK4, were expressed in the ovary, testis, oocytes, embryo, and sperm. Out of these channels, KCNK2 and KCNK4 mRNAs were abundantly expressed in the mature oocytes, eight-cell stage embryos, and blastocysts compared with immature oocytes. KCNK4 and KCNK3 were significantly increased in eight-cell stage embryos. Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed at the membrane of oocytes and blastocysts. KCNK10 and KCNK4 were strongly expressed and distributed in oocyte membranes. These channel proteins were also localized to the acrosome sperm cap. In particular, KCNK3 and KCNK4 were strongly localized to the post-acrosomal region of the sperm head and the equatorial band within the sperm head respectively. These results suggest that K(2P) channels might contribute to the background K(+) conductance of germ cells and regulate various physiological processes, such as maturation, fertilization, and development. 相似文献
73.
Jeon BW Jeong JM Won GY Park H Eo SK Kang HY Hur J Lee JH 《International journal of food microbiology》2006,110(2):123-126
Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome worldwide. E. coli O26 and O111 are the serotypes most frequently isolated from human EHEC infections in Korea. Cattle are considered to be the major sources of E. coli O26 and O111. This study investigated the prevalence of E. coli O26 and O111 in fecal samples from cattle in Korea from April 2002 to March 2004. Out of 809 samples, 54 (6.67%), 37 (4.57%), and 16 (1.98%) tested positive for O26, O111, and both O26 and O111, respectively. Most of the E. coli O26 and O111 strains were isolated from May to October of each year. PCR analysis of the EHEC virulence markers revealed that most of the E. coli O26 and O111 isolates were positive for ehxA, eaeA and stx1 and/or stx2. These results suggest that the majority of Korean E. coli O26 and O111 isolates from cattle can cause serious diseases in humans. 相似文献
74.
We have successfully fabricated piezoelectric PMN-PT single crystal cantilever array. Each PMN-PT cantilever has a different
length to achieve different resonance frequencies. The width and thickness of PMN-PT cantilever array are 200 μm and 10 μm,
respectively. Resonance frequencies of PMN-PT cantilevers were measured with laser interferometer, and charge sensitivity
was measured with charge-measuring device. PMN-PT cantilever array was installed in a noise-shield case. The array was then
exposed to sound pressure frequency corresponding to resonance frequency to measure its sensitivity. The experimental results
show that the PMN-PT cantilever array has high sensitivity to the sound pressure. This implies that the single crystal PMN-PT
cantilever array is a potential candidate for a cochlear-like acoustic sensor. 相似文献
75.
Soo-Haeng Cho Seung-Chul Oh Seong-Bin Park Kwang-Mo Ku Jong-Hyeon Lee Jin-Mok Hur Han-Soo Lee 《Metals and Materials International》2012,18(6):939-949
The high temperature corrosion behavior of N07263, N06600, and N06625 in LiCl-Li2O molten salt was investigated at temperatures ranging from 650 to 850 °C in a glove box. The high temperature corrosion behavior was observed using measurements of the oxide morphology and thickness, the extent of internal corrosion, and the compositional changes in the scale and in the substrate. Corrosion tests were performed, and these demonstrated that the main corrosion products were Fe(Ni,Co)3, FeNi3, and LiCrO2. The internal corrosion of N07263 was localized, while that of N06600 maintained intergranular corrosion throughout the test temperature range. N06625 exhibited uniform intergranular corrosion behaviors at low and high temperatures. N07263 exhibited superior corrosion resistance, as evidenced by its corrosion layer which was more continuous, dense, and adherent when compared with those of N06600 and N06625. 相似文献
76.
Vignolini S Yufa NA Cunha PS Guldin S Rushkin I Stefik M Hur K Wiesner U Baumberg JJ Steiner U 《Advanced materials (Deerfield Beach, Fla.)》2012,24(10):OP23-OP27
Optical metamaterials have unusual optical characteristics that arise from their periodic nanostructure. Their manufacture requires the assembly of 3D architectures with structure control on the 10-nm length scale. Such a 3D optical metamaterial, based on the replication of a self-assembled block copolymer into gold, is demonstrated. The resulting gold replica has a feature size that is two orders of magnitude smaller than the wavelength of visible light. Its optical signature reveals an archetypal Pendry wire metamaterial with linear and circular dichroism. 相似文献
77.
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79.
Effects of yuja peel extract and its flavanones on osteopenia in ovariectomized rats and osteoblast differentiation 下载免费PDF全文
80.
Hyun-Moo Hur Joon-Hyuk Park Won-Hee You Tae-Won Park 《Journal of Mechanical Science and Technology》2009,23(10):2790-2800
A study was conducted to analyze the influence of wheel profile wear on running stability by using a 1/5 scale bogie model.
The critical speed was analyzed by constructing a dynamic model for the bogie model. And the 1/5 scale bogie and a scaled
roller rig prototype were manufactured to verify the feasibility of applying the scale model; a critical speed test was conducted
for worn wheel profile samples. The test results for the scale model were consistent with the simulation results for the scale
model within the range of 5% or less. Also, the variation of the critical speed of the scale model for the wheel profile wear
shows a similar trend with the analysis results of the full scale model. Therefore, using the scale model to analyze the influence
of wheel profile wear on running stability shows sufficient feasibility as a model to analyze the stability of a full scale
bogie. 相似文献