• Biomolecules & Therapeutics
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• 제24권4호
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• pp.410-417
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• 2016

Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin-3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we showed that quercetin can enhance ${\alpha}7$ nicotinic acetylcholine receptor (${\alpha}7$ nAChR)-mediated ion currents. However, the role of the carbohydrates attached to quercetin in the regulation of ${\alpha}7$ nAChR channel activity has not been determined. In the present study, we investigated the effects of quercetin glycosides on the acetylcholine induced peak inward current ($I_{ACh}$) in Xenopus oocytes expressing the ${\alpha}7$ nAChR. $I_{ACh}$ was measured with a two-electrode voltage clamp technique. In oocytes injected with ${\alpha}7$ nAChR copy RNA, quercetin enhanced $I_{ACh}$, whereas quercetin glycosides inhibited $I_{ACh}$. Quercetin glycosides mediated an inhibition of $I_{ACh}$, which increased when they were pre-applied and the inhibitory effects were concentration dependent. The order of $I_{ACh}$ inhibition by quercetin glycosides was Rutin${\geq}$Rham1>Rham2. Quercetin glycosides-mediated $I_{ACh}$ enhancement was not affected by ACh concentration and appeared voltage-independent. Furthermore, quercetin-mediated $I_{ACh}$ inhibition can be attenuated when quercetin is co-applied with Rham1 and Rutin, indicating that quercetin glycosides could interfere with quercetin-mediated ${\alpha}7$ nAChR regulation and that the number of carbohydrates in the quercetin glycoside plays a key role in the interruption of quercetin action. These results show that quercetin and quercetin glycosides regulate the ${\alpha}7$ nAChR in a differential manner.

• Journal of Chest Surgery
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• 제33권5호
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• pp.398-406
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• 2000

Background: Cardiac atrium is an endocrine gland secreting a family of natriuretic peptides. The secretion of atrial natriuretic peptide(ANP) had been shown to be controlled by variable factors. The change in atrial dynamics have been considered as one of the most prominent stimuli for the stimulation of ANP secretion. Hypoxic stress has been shown to increase cardiac ANP secretion. However, the mechanism by which hypoxia increases ANP secretion cardiac ANP secretions. However, the mechanism by which hypoxia increases ANP secretion has not to be defined. Therefore, the purpose of the present study was tow-fold: to develop a protocol to defined the effect of hypoxia on ANP secretion in perfused beating rabbit atria and to clarify the mechanism responsible for the accentuation by hypoxia of ANP secretion. Material and Method: Experiments have been done in perfused beating rabbit atria. ANP was measured by radioimmunoassay. Result: Hypoxic stimulus with nitrogen decreased atrial stroke volume. The decrease in atrial stroke volume recovered basal level during the period of recovery with oxygen. ANP secretion and the concentration of perfusate ANP in terms of extracellular fluid(ECF) translocation which reflects the rate of myocytic release of ANP were increased by hypoxia and returned to basal levels during the recovery. Changes in ECF translocation paralleled by hypoxia and returned to basal levels during the recovery. Changes in ECF translocation paralleled to that of atrial stroke volume. At the start of recovery in atrial storke volume, ECF tranalocation incrased for several minutes. The above responses were stable and reproducible. Glibenclamide treatment prevented the recovery in atrial stroke volume. Increments by hypoxia of ANP secretion and ANP concentration were suppressed by glibenclamide. Conclusion: These results indicate that hypoxia incrased atrial myocytic ANP release and that the mechanism responsible for the accentuation is partially related to the change in K+ATP channel activity.

• Investigative Magnetic Resonance Imaging
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• 제8권1호
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• pp.1-8
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• 2004

목적: MRI를 촬영하면서 뇌전도 신호를 동시에 측정하는 것은 뇌기능 영상에 있어 매우 필요한 일이다. 그러나 MRI와 동시에 측정한 뇌전도 신호에는 많은 잡음이 유발되는데 이중 가장 심각한 영향을 주는 것은 경사자계에 의해서 유발되는 잡음이다. 경사자계 유발잡음을 ICA를 이용하여 효과적으로 제거하는 방법을 개발하고자 한다. 대상 및 방법: 29채널의 MR-compatible 뇌전도 측정시스템과 3.0 T MRI 시스템을 실험에 사용하였다. 3.0 T MRI 시스템 안에 뇌전도 캡을 쓴 피험자를 놓고 EPI 촬영을 하면서 뇌전도 신호를 측정하였다. 측정된 뇌전도 신호에 대하여 ICA를 적용해 경사자계 유발 잡음을 선택적으로 제거하였다. 제거한 결과를 평균화 방법과 PCA 방법을 사용해 얻은 결과와 비교하였다. 결과: ICA 방법, 평균화 방법 , PCA 방법 모두 경사자계 유발잡음 제거에 있어 일정 부분 효과가 있었다. 그러나 이들 방법들을 상호 비교하였을 때 잡음 제거 결과는 ICA 방법이 평균화 방법과 PCA 방법에 비해 우수하였다. 결론: ICA를 이용하여 경사자계 유발 잡음을 효과적으로 제거할 수 있었다. 잡음이 제거된 뇌전도 신호는 간질환자에 대한 뇌기능영상이나 뇌전도결합 fMRI 촬영에 활용될 수 있을 것이다.

• The Korean Journal of Physiology and Pharmacology
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• 제15권1호
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• pp.17-22
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• 2011

Quercetin mainly exists in the skin of colored fruits and vegetables as one of flavonoids. Recent studies show that quercetin, like other flavonoids, has diverse pharmacological actions. However, relatively little is known about quercetin effects in the regulations of ligand-gated ion channels. In the previous reports, we have shown that quercetin regulates subsets of homomeric ligand-gated ion channels such as glycine, 5-$HT_{3A}$ and ${\alpha}7$ nicotinic acetylcholine receptors. In the present study, we examined quercetin effects on heteromeric neuronal ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor channel activity expressed in Xenopus oocytes after injection of cRNA encoding bovine neuronal ${\alpha}3$ and ${\beta}4$ subunits. Treatment with acetylcholine elicited an inward peak current ($I_{ACh}$) in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor. Co-treatment with quercetin and acetylcholine inhibited $I_{ACh}$ in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptors. The inhibition of $I_{ACh}$ by quercetin was reversible and concentration-dependent. The half-inhibitory concentration ($IC_{50}$) of quercetin was $14.9{\pm}0.8\;{\mu}M$ in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor. The inhibition of $I_{ACh}$ by quercetin was voltage-independent and non-competitive. These results indicate that quercetin might regulate ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor and this regulation might be one of the pharmacological actions of quercetin in nervous systems.

• 대한의용생체공학회:의공학회지
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• 제39권3호
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• pp.124-133
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• 2018

We tried to investigate the changes in cortical activities according to emotional valence states during watching video clips. We examined the neural basis of two emotional states (positive and negative) using spectral power analysis and brain functional connectivity analysis of cortical current density time-series reconstructed from high-density electroencephalograms (EEGs). Fifteen healthy participants viewed a series of thirty-two 2 min emotional video clips. Sixty-four channel EEGs were recorded. Distributed cortical sources were reconstructed using weighted minimum norm estimation. The temporal and spatial characteristics of spectral source powers showing significant differences between positive and negative emotion were examined. Also, correlations between gamma-band activities and affective valence ratings were determined. We observed the changes of cortical current density time-series according to emotional states modulated by video clip. Gamma-band activities showed significant difference between emotional states for thirty seconds at the middle and the latter half of the video clip, mainly in prefrontal area. It was also significantly anti-correlated with the self-ratings of emotional valence. In addition, the gamma-band activities in frontal and temporal areas were strongly phase-synchronized, more strongly for negative emotional states. Cortical activities in frontal and temporal areas showed high spectral power and inter-regional phase synchronization in gamma-band during negative emotional states. It is inferred that the higher amygdala activation induced by negative stimuli resulted in strong emotional effects and caused strong local and global synchronization of neural activities in gamma-band in frontal and temporal areas.

• Archives of Pharmacal Research
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• 제28권1호
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• pp.61-67
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• 2005

We evaluated the antiplatelet effects of two classes of ATP-sensitive potassium channel openers $(K_{ATP}\;openers)$ on washed human platelets, and the study's emphasis was on the role of mitochondrial $K_{ATP}$ in platelet aggregation. Collagen-induced platelet aggregation was inhibited in a dose dependent manner by lemakalim and SKP-450, which are potent cardio-nonselective $K_{ATP}$ openers, and also by cardioselective BMS-180448 and BMS-191095 $(IC_{50}\;:\;1,130,\;>\;1,500,\;305.3\;and\;63.9\;{\mu}M,\;respectively)$, but a significantly greater potency was noted for the cardioselective $K_{ATP}$ openers. The latter two $K_{ATP}$ openers also inhibited platelet aggregation induced by thrombin, another important blood-borne platelet activator, with similar rank order of potency $(IC_{50}\;:\;498.0\;and\;104.8{\mu}M\; for\;BMS-180448\;and\;BMS-191095,\;respectively)$. The inhibitory effects of BMS-191095 on collagen-induced platelet aggregation were significantly blocked by a 30-min pretreatment of platelets with glyburide $(1{\mu}M)$ or sodium 5-hydroxyde­canoate$(5-HD,\;100{\mu}M)$, a nonselective and selective mitochondrial $K_{ATP}$ antagonist, respectively, at similar magnitudes; this indicates the role of mitochondrial $K_{ATP}$ in the antiplatelet activity of BMS-191095. However, glyburide and 5-HD had no effect when they were added to the platelet cuvette immediately prior to the addition of BMS-191095. These findings indicate that cardioselective mitochondrial $K_{ATP}$ openers like BMS-191095 are able to exert cardioprotective effects in cardiac ischemia/reperfusion injury via dual mechanisms directed at the inhibition of platelet aggregation and the protection of cardiomyocytes, and both these mechanisms are mediated by mitochondrial$K_{ATP}$.

• 대한조선학회논문집
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• 제54권5호
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• pp.406-414
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• 2017

An experimental study in a recirculating water channel was carried out to investigate the effect of large coherent structures to the skin friction on a flat plate. Particle Image Velocimetry (PIV) technique was used to quantify characteristic features of coherent structures growing to the boundary layer. In the PIV measurement, it is difficult to calculate the friction velocity near the wall region due to laser deflection and uncertainty so that Clauser fitting method at the logarithmic region was adopted to compute the friction velocity and compared with the one directly measured by the dynamometer. With changing the free-stream velocity from 0.5 m/s to 1.0 m/s, the activity of coherent structures in the logarithmic region was increased over three times in terms of Reynolds stress. The flow field was separated by Variable Interval Time Averaging (VITA) technique into the weak and the strong structure case depending on the existence large coherent structures in order to validate its effectiveness. The stream-wise velocity fluctuation was scanned through at the boundary thickness whether it had a large deviation from background flow. With coherent structures connected from near-wall to the boundary layer, mean wall shear stress was higher than that of weak structure case. Proper Orthogonal Decomposition (POD) analysis was also applied to compare the energy budget between them at each free-stream velocity.

• Journal of Ginseng Research
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• 제35권4호
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• pp.471-478
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• 2011

Ginseng, the root of Panax ginseng, is one of the oldest herbal medicines. It has a variety of physiological and pharmacological effects. Recently, we isolated a subset of glycolipoproteins that we designated gintonin, and demonstrated that it induced transient change in intracellular calcium concentration $([Ca^{2+}]_i)$ in cells via G-protein-coupled receptor signaling pathway(s). The previous method for gintonin isolation included multiple steps using methanol, butanol, and other organic solvents. In the present study, we developed a much simple method for the preparation of gintonin from ginseng root using 80% ethanol extraction. The extracted fraction was designated edible gintonin. This method produced a high yield of gintonin (0.20%). The chemical characteristics of gintonin such as molecular weight and the composition of the extract product were almost identical as the gintonin prepared using the previous extraction regimen involving various organic solvents. We also examined the physiological effects of edible gintonin on endogenous $Ca^{2+}$-activated $Cl^-$ channel activity of Xenopus oocytes. The 50% effective dose was $1.03{\pm}0.3\;{\mu}g$/mL. Finally, since gintonin preparation through ethanol extraction is easily reproducible, gintonin could be commercially applied for ginseng-derived functional health food and/or drug following the confirmations of in vitro and in vivo physiological and pharmacological effects of gintonin.

• 감성과학
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• 제8권2호
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• pp.95-101
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• 2005

본 연구는 관상동맥 질환(coronary artery disease : CAD) 환자의 심장 부교감신경 활성화가 감소하고, 만성 심부전(chronic heart failure : CHF) 환자의 심박동변이도(heart rate variability : HRV)에서 정상적 RR 간격의 분산(SDNN : standard deviation of all normal RR intervals)과 저주파수 대역의 전력스펙트럼(low-frequency power : LF),그리고 복잡성이 감소하며, CAD환자의 우측으로 누운 자세에서 HRV의 규격화된 고주파수대역의 전력스펙트럼(normalized high-frequency power : nHF)가 3가지 누운 자세 중에서 가장 높다는 사전 정보에 근거하였다. 세 가지 누운 자세에 대한 HRV의 비선형 특징은 알려진 바가 없으므로, 본 연구에서는 관상동맥질환 환자들을 대상으로 누운 자세에서 HRV의 선형과 비선형특성을 조사하였다. 이 목적을 위하여, 관상동맥질환군 29명과 통제군 23명을 대상으로 세 가지 누운 자세에서 심전도의 Lead II 채널을 측정한 뒤, 심전도로부터 심박동변이도의 선형특성(시간영역과 주파수영역)과 비선형특성을 분석하였다. 똑바로 누운 자세 또는 좌측으로 누운 자세에서 심박동변이도의 nHF가 더 작을수록, 이 자세들로부터 우측으로 누운 자세로 전환할 때 nHF가 더욱 증가하였다. 중증의 관상동맥질환 환자의 세 가지 누운 자세 중에서, 우측으로 누운 자세는 심장부교감신경계의 활성도를 가장 높게, 심장교감신경계의 활성도는 가장 낮게, 그리고 생체시스템의 복잡성은 가장 높게 유도함을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1599-1607
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• 2004

This study examined the effects of pre-slaughter fasting, chasing stress and chiller ageing on objective meat quality, and their relations to the proteome profile of longissimus muscle using 20 male Korean native black pigs. Treatments were composed of two levels of pre-slaughter feed withdrawal, two levels of pre-slaughter stress and four chiller ageing times. A 15 min chasing stress immediately prior to slaughter significantly (p<0.05) decreased detectable levels of $\mu$-calpain activity during rigor development and chiller ageing, but did not have any direct effect on objective meat quality. On the other hand, pigs fed until the morning of slaughter resulted in significantly (p<0.05) higher hunter L* value and cooking loss than those which received an 18 h feed withdrawal prior to slaughter. Cooking loss and hunter L* value were constant during 7 d of chiller ageing, followed by significant increases at 14 d. The fed animals showed a significantly (p<0.05) higher hunter a* value at both 3 and 7 d, while the other group maintained a stable redness for 7 d. WB-shear force was not affected by the pre-slaughter treatments, but had significant (p<0.05) linear reduction from 1 to 7 d. A gelbased proteome analysis was performed on selected animals for low and high hunter L* values at 1 d. Ten and five spots had greater than two-fold spot densities for the low and high hunter L* groups, respectively. The ten spots included chain A, deoxyribounclease I complex with actin, heat shock protein 27 kDa, a protein similar to cardiac $Ca^{2+}$ release channel, and myosin heavy chain, while the five spots included chain A aldehyde dehydrogenase, glycerol-3 phosphate dehydrogenase, and hemoglobin alpha chain. In general, feeding until the morning of slaughter resulted in more desirable meat color, but appeared to reduce palatability due to increased cooking loss. Proteome analysis demonstrated that various proteins were concomitantly involved in the determination of final meat color. The most noticeable observation in the current study was that various isoforms for a particular protein differed in degradation and/or expression rate depending on meat quality.