• The Korean Journal of Physiology and Pharmacology
• /
• v.9 no.5
• /
• pp.255-262
• /
• 2005

Striatum is involved in the control of movement and habitual memory. It receives glutamatergic input from wide area of the cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from the raphe nuclei. In our study, the effects of 5-HT on synaptic transmission were studied in the rat corticostriatal brain slice using in vitro whole-cell recording technique. 5-HT inhibited the amplitude as well as frequency of spontaneous excitatory postsynaptic currents (sEPSC) significantly, and neither ${\gamma}-aminobutyric$ acid (GABA)A receptor antagonist bicuculline (BIC), nor $N-methyl-_{D}-aspartate$ (NMDA) receptor antagonist, $_{DL}-2-amino-5-phosphonovaleric$ acid (AP-V) could block the effect of 5-HT. In the presence non-NMDA receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenxo[f] quinoxaline-7-sulfonamide (NBQX), the inhibitory effect of 5-HT was blocked. We also figured out that 5-HT change the channel kinetics of the sEPSC. There was a significant increase in the rise time during the 5-HT application. Our results suggest that 5-HT has an effect on both pre- and postsynaptic site with decreasing neurotransmitter release probability of glutamate and decreasing the sensitivity to glutamate by increasing the rise time of non-NMDA receptor mediated synaptic transmission in the corticostriatal synapses.

• Toxicological Research
• /
• v.14 no.4
• /
• pp.483-488
• /
• 1998

During cerebral ischemia two important factors such as hypoxia and reduction of glucose can act as modulating stressor affecting the release of amine neurotransmitters including 5-hydroxytryptamine (5-HT). This study was performed to investigate the effect of glucose deprivation on the oxygen deprivation-induced changes of [3H]-5-HT release in the rat hippocampal slices. Experimental groups were divided into 4 groups for this study: normoxic/normoglycemic group, oxygen-deprived group, glucose-deprived group, and oxygen/glucose-deprived group. The hippocampus of rat brain was sliced by 400 $\mu\textrm{m}$ thickness with manual chopper. After 30 minutes preincubation in the normal buffer, the slices were incubated for 20 min in buffer containing [3H]-5-HT (0.1 M, 74 $\mu\textrm$Ci) for uptake. To measure the release of [3H]-5-HT into the buffer, the incubation medium was drained of and refilled with fresh buffer every ten minutes through a sequence of 14 tubes. Oxygen deprivation by gassing with 95% $N_2$/5% $CO_2$ and/or glucose deprivation was done in the 6th and 7th tube. The radioactivities in each buffer and the tissue were counted using scintillation counter. The results were expressed as fractional release. When slices were exposed to oxygen-deprived media for 20 min, the diminution followed by the rebound release of [3H]-5-HT was observed during the post-oxygen deprived period. However, glucose deprivation or oxygen/glucose deprivation markedly increased the release of [3H]-5-HT. which was opposite to the pattern observed in oxygen-deprived group. These results suggested that oxygen deprivation itself inhibits [3H]-5-HT release in rat hippocampal slices during oxygen-deprived period, but additional glucose deprivation convert the inhibitory response to increase of [3H]-5-HT release.

• Journal of agriculture & life science
• /
• v.53 no.3
• /
• pp.17-26
• /
• 2019

Chamaecyparis obtusa is one of the economical conifers planted in Korea due to its good quality timber and wood characteristics. Individuals of C. obtusa containing high terpenes (HT) and low terpenes (LT) were selected for by colorimetric method. The HT of C. obtusa was delayed in wilting against various abiotic stresses compared to the LT plants. The HT group exposed to UV did not significant influence the chlorophyll content, and the chlorophyll value was higher in the HT group than the LT group. Also, chilling treatment (5℃) did not significant influence on the chlorophyll content. However treatment at -4℃ showed relatively low chlorophyll content in the LT group than the HT group. Plants exposure to high temperature was not a difference between the HT and the LT group. However, treatment at 38℃ influenced the chlorophyll content that was increased exposure time-dependently. In salt treatments, chlorophyll in the HT group was lower at high concentrations (300 and 500 mM) of NaCl. However, chlorophyll content increased to slightly in treatment time-dependently, which is 6.7% to 40%. H2O2 treatment has been a negative effect on the chlorophyll content in the HT group. All concentration of H2O2 decreased the chlorophyll content of 5% to 35%. Plants containing high terpenoids were resisted against some abiotic stress such as salt and H2O2. Our results implied that terpenoids could cause various abiotic stress resistance. These results could be utilized for efficient management and biomass production during forest silvicultures.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.7
• /
• pp.886-890
• /
• 2017

In this study, the protective effect of rice with Phellinus linteus mycelium (PLMR) against hydrogen peroxide-induced oxidative stress was assessed in a mouse hippocampal neuronal HT22 cell line through (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) salt (MTS) assay and western blot. MTS assay using HT22 cells showed that PLMR extract did not affect viability at a concentration range from 1 mg/mL to 5 mg/mL. However, at concentrations over 10 mg/mL, PLMR extract resulted in increased cell death. Cell viability of HT22 was significantly reduced by $H_2O_2$ treatment, and reduction of cell viability was efficiently restored by treatment with PLMR extract in a dose-dependent manner from 0.1 to 1 mg/mL. Cells treated with $H_2O_2$ showed increased expression of Bax, a pro-apoptotic protein, which was down-regulated by treatment with PLMR extract. On the other hand, cells treated with $H_2O_2$ resulted in reduced expression of Bcl-2, an anti-apoptotic protein, which was restored by treatment with PLMR extract. In addition, treatment with PLMR extract reduced expression of cleaved caspase 3 and PARP, which were up-regulated by $H_2O_2$ treatment. The results may suggest that treatment with PLMR extract would suppress $H_2O_2$-induced apoptosis of HT22 cells.

• KSBB Journal
• /
• v.27 no.4
• /
• pp.227-231
• /
• 2012

Whole plants of Zostera asiatica were extracted twice with acetone/methylene chloride (A+M) and methanol (MeOH) in turn. The combined crude extracts were evaporated in vacuo and then the residue was partitioned between water and methylene chloride. The aqueous layer was fractionated into $H_2O$ and n-butanol and then the organic layer was also fractionated into 85% aq. MeOH and n-hexane, successively. The crude extracts and their solvent fractions were evaluated for their inhibitory effect on growth of human cancer cells AGS, HT-29, MCF-7, and HT-1080 cells by MTT reduction assay. Among samples tested, 85% aq. MeOH and n-hexane fractions showed strong cytotoxic effect against AGS, HT-29, and MCF-7 cells. On the other hand, for HT-1080 cell, 85% aq. MeOH fraction exhibited the strongest cytotoxic effect.

• Fibers and Polymers
• /
• v.1 no.1
• /
• pp.25-31
• /
• 2000

Poly(3-hexyl thiophene)(P3HT) and poly(3-dodecyl thiophene)(P3DT) were polymerized by oxidative coupling with ferric chloride. The P3HT light-emitting device emitted red light and it could be observable in the ordinary indoor light. The device had the turn-on electric field of about 3$\times$$10^7$ V/m. The maximum electroluminescene (EL) intensity was obtained when the thickness of polymer layer was about 130 nm in IT0/P3HT/Al device. The maximum external quantum yield was 0.002%. The maximum luminance was 21 cd/$m^2$. The EL intensity decreases with increasing the crystallinity of the polymer layer. By using the oriented poly(3-alkyl thiophene)(PAT) layer as an electroluminescent layer in the ITO/polymer/Al light-emitting devices, the polarized EL light emission was observed. The EL intensity ratio of parallel to perpendicular direction to the stretch direction for P3HT was about 1.40.

• Corrosion Science and Technology
• /
• v.5 no.3
• /
• pp.94-98
• /
• 2006

The next generation nuclear power reactor will use Pb-Bi as the cooling material. The steel structure materials such as HT-9 used in the reactor suffer from corrosion when they are exposed to high temperature Pb-Bi. Therefore corrosion should be prevented to use Pb-Bi as the coolant material without any safety problem. One method is to control the oxygen content in Pb-Bi. An appropriate amount of oxygen in Pb-Bi can produce a thin oxide layer on steel, and this layer protects the steel from corrosion attack. Since the required oxygen content in Pb-Bi is in the range of $10^{-5}$ to $10^{-7}$ wt%, this small oxygen content can be controlled by flowing a mixture of hydrogen gas and water vapor. The stagnant corrosion test of HT-9 samples was performed by controlling the oxygen content up to 2,000 hours. The corrosion behavior of HT-9 was analyzed at the temperatures of $500^{\circ}C$ and $650^{\circ}C$ with a reduced condition and a oxygen content of $10^{-6}$ wt%.

• Journal of Korea Technology Innovation Society
• /
• v.7 no.2
• /
• pp.283-304
• /
• 2004

Evaluating the sources of economic output is obviously important, and numerous attempts have been made to judge the impact of many different factors on economic output. It is widely accepted that high-technology(HT) is one of the important factors in economic output. This paper empirically explores the impacts of HT exports on economic output using a cross-county analysis based on data from 89 countries for the year 1988-2000. To this end, several versions of the neoclassical growth models, explicitly including HT exports, are estimated. Subject to the appropriate caveats, the results provide further support for several key conclusions of the former studies - investment in physical capital, population growth, and the human capital are important in accounting fer economic output across countries. More importantly, it is concluded that HT exports significantly contribute to economic output. Interestingly, the conclusion is valid f3r developing countries, but not far developed countries.

• The Korean Journal of Pharmacology
• /
• v.17 no.2
• /
• pp.47-62
• /
• 1981

d-amphetamine이 사람에서 paranoid schizophrenia와 아주 유사한 model psychosis를 일으키며 또한 사람과 실험동물에서 실제 정신분열증에서 뚜렷이 관찰되는 behavioral perservation을 일으킬 수 있음이 관찰되었다. 이에 많은 학자들은 이러한 양상의 행동변화가 정신분열증의 원인 추구에 중요한 의미를 주는 뇌변화를 반영할지도 모른다는 생각에 많은 연구를 거듭하여 왔다. 지금까지는 주로 catecholamine기전에 대하여 집중적 연구가 수행되어져 왔으나 최근에는 d-amphetamine의 약리기전의 일부는 5-HT기전이 차지하고 있으며, 여러 행동변화에는 catecholaimin 보다 5-HT 가 더 중요하게 관계하고 있다는 주장이 나오고 있다. 또한 d-amphetamine은 시험관내에서 MAO 특히 신경전달물질 분해요소인 A type를 가역적으로 억제할 수 있음이 보고되어 많은 흥미를 끌어왔으나 생체내에서의 억제여부는 직접적으로 확인이 되고 있지 않다. 그러나 최근에 Braestrup(1977)과 El Hait(1978)등은 간접적인 방법으로 생체내에서도 억제시킬 수 있음을 보고하고 있다. 이에 저자는 d-amphetamine에 의해 야기되는 행동변화와 그 밑바탕을 이루는 생화학적 기전에 5-HT가 차지하는 역할을 알아보기 위해서 다음의 실험을 시행하였다. 첫째, d-amphetamine의 급성, 만성 투여가 5-HT의 5-HIAA 로의 turnover와 MAO활성도에 어떤 영향을 미치며, 더 나아가서 이 양자사이에 어느 정도 상관관계가 있는지를 알아보기 위해서 d-amphetamine을 투여한 후 시간 경과에 따라서 뇌내 5-HT, 5-HIAA, 5-HT turnover rate와 MAO 활성도를 측정하였다. 둘째, d-amphetamine, 5-HT 합성을 증가시키는 약물과 합성을 억제시키는 약물을 투여하고, 위의 생화학적 실험과 행동관찰을 병합 실시하여 비교분석하였다. 그 결과는 다음과 같다. 1) d-amphetamine (6 mg/kg)을 급성투여시, 뇌내 5-HT함량이 투여 1시간 후에 최고로(대조치의 123%, p<0.001) 증가되다가 이후 감소하며, 5-HIAA 함량은 처음 15분부터 감소하기 시작하다가 30분에 최저로 떨어지며(대조치의 78%, p<0.005) 이후 증가하여 24시간째는 약간 대조치 이상으로 회복되었다. 미토콘드리아 MAO활성도는 1시간째에 최저로 떨어지다가(대조치의 89%, p<0.05)이후 회복하기 시작하여 24시간째에 약간 대조치 이상으로 회복되었다. 5-HT의 turnover rate는 MAO활성도 변화와 거의 같은 변화를 보였다. 2) 만성투여시 (하루 2번, 14일간 투여)는 5-HT 함량, 5-HIAA 함량, MAO 활성도 및 5-HT turnover rate 모두가 중등도로 감소되었다. (각각 대조치의 87%, 69%, 80%, 79%). 3) MAO 활성도와 5-HT turnover rate 사이에는 높은 상관관계가 있었다. (r=0.866, p<0.001, N=94). 4) MAO 활성도의 역동학 실험에서는 대조치에 비해 투여군에서 Km 값은 의미가 있는 증가가 있었으나 $V_{max}$값은 큰 변동이 없었다. 5) d-amphetamine을 급성 투여할때는 sleeping과 lying components는 상당한 감소를 보인 반면, locomotor activity 는 1시간까지는 상당한 증가를 보였으며 용량이 적을수록 더 큰 증가가 있었다. 반면 stereotypy는 1시간까지 용량이 증가할수록 더 큰 증가가 나타나서 locomotor activity에서 stereotypy 의 증가로 이행을 나타내었다. 만성 투여시는 locomotor activity는 점차적인 감소를 보였으나 stereotypy는 점차적인 증가가 나타나서 14일쯤에는 평형에 도달하였다. 6) PCPA 단독 투여군(400 mg/kg, 3번)에 있어서는 5-HT와 5-HIAA 함량의 상당한 감소가 나타났으나 MAO 활성도와 행동에는 큰 변화를 나타내지 않았다. PCPA전 처치군에 있어서도 5-HT와 5-HIAA 함량은 마찬가지로 상당한 감소를 나타내었으나 gnawing, sniffing과 locomotor activity는 더 증가를, stereotyped head weaving, forepaw treading과 hindlimb abduction은 상당한 감소를 나타내었다. 7) L-tryptophan(100 mg/kg)단독 투여시는 5-HT 함량은 약간 증가를 나타내었으나 5-HIAA 함량은 상당한 증가를 보였다. MAO활성도나 행동은 큰 변화없었다. L-tryptophan 전처치군에 있어서는 5-HT 함량은 더 큰 증가를 보였으나, 5-HIaa 함량은 MAO 활성도는 별 변화없었으며 stereotypedlateral head waving, forepaw treading 과 hindlimb abduction은 증가를, locomotor activity, gnawing과 sniffing components는 감소를 나타내었다. 8) d-amphetamine 단독투여, 혹은 L-tryptophan 전처치, PCPA 전처치후 측정한 5-HT 함량과 stereotyped head weaving, forepaw treading, hinilimb abduction components 사이에는 높은 상관관계가 있었다(r=0.789, p<0.001). 반면 5-HT 함량과 locomotor activity, stereotyped gnawing과 sniffing components 사이에는 약한 음성의 상관관계가 있었다. (r=0.554, p <0.005). 이상의 결과로 미루어 볼때 5-HT의 5-HIAA 로의 turnover rate 는 주로 MAO 활성도에 의해서 조절되며 5-HT 기전이 d-amphetamine에 의해서 야기된 여러 행동변화 중 상당한 부분에서 중요한 역할을 하리라고 생각된다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.4
• /
• pp.431-438
• /
• 2007

In the present study, twenty eight marine algae species were evaluated for their antiproliferative effect on HT-29 human colon cancer cells. Among these, the methanolic extract of Symphyocladia latiuscula (SL Ex) showed the highest inhibitory activity on HT-29 cell growth. In this study, we examined the mechanism by which SL Ex inhibited the HT-29 cell growth. Cells were cultured with various concentrations of $(0{\sim}20{\mu}g/mL)$ SL Ex. The SL Ex substantially decreased the viable cell numbers and induced apoptosis of HT-29 cells in a dose-dependent manner Western blot analyses of total cell lysates revealed that SL Ex increased the levels of cleaved caspase-8, -9, -7, and -3, and poly (ADP-ribose) polymerase in HT-29 cells. In addition, SL Ex increased truncated Bid levels but moderately decreased Bax levels at only $20{\mu}g/mL$. Furthermore, SL Ex did not affect Bcl-2 protein levels but increased the levels of Fas in HT-29 cells. The present results indicate that SL Ex inhibits cell growth via inducing apoptosis in human colon cancer cells. The mechanism of apoptosis induction by SL Ex involves caspase-8 activation leading to changes in mitochondrial events and subsequent activation of the caspase-7/caspase-3 cascade. Our finding may lead to the development of new therapeutic strategies for the treatment of colon cancer.