• YAKHAK HOEJI
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• v.51 no.3
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• pp.219-227
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• 2007

Ginsenoside Rgl (Rgl), the pharmacologically active constituent of ginseng (Panax ginseng C.A. Meyer), has a variety of biological activities. The present study was undertaken to evaluate a possibility of Rgl whether it can be used in treatment or prevention of stress disorders. Animals were stressed by immobilization for 2 hours or electroshocks for 20 minutes. The normal group was not exposed to any stress. Rgl was subcutaneously injected as dosages of 5 and 10 mg/kg and red ginseng (RG) was orally administered 200 mg/kg as the positive control. Animals were given supplements for 5 days without stress, and then were given supplements for 5 days with stress. We recorded stress-related behavioral changes of experimental animals using the Etho-vision system. Weight of adrenal gland and levels of corticosterone in plasma were measured and stress related behaviors (smelling, grooming, face washing, rearing) were observed. Rgl didn't make significant behavioral changes in total open field and elevated plus maze test. Rgl did not influence on behavioral changes induced by electroshock stress. Whereas, 10 mg/kg of Rgl alleviated the increment of the freezing and face washing time and the decrement of the smelling and rearing time induced by restraint stress. The administration of Rgl 10 mg/kg has significantly increased the endurance time on rotating rod and swimming pool tests compared to the control group. These results indicate that Rgl can alleviate the damage induced by physical stress. This result suggests that Rgl may bea new candidate for treating stress related disorder.

• Journal of Ginseng Research
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• v.34 no.1
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• pp.30-40
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• 2010

The present investigation was conducted to evaluate the regulation of sleep architecture by the red ginseng water extract (RGE) in acutely and chronically restraint stressed rats. Adult rats were fitted with sleep.wake recording electrodes. Following post-surgical recovery, rats were extensively habituated for freely moving polygraphic recording conditions. Polygraphic signs of sleep-wake activities were recorded for 24 h after RGE administration and induction of stress and were analyzed to understand the regulation of sleep architecture. Acute stress decreased wakefulness and increased total sleep, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep in both the daytime and nighttime recording. RGE shortened the daytime NREM and REM sleep, without changing the wakefulness and total sleep. RGE increased nighttime wakefulness, and decreased total, NREM and REM sleep. Chronic stress increased wakefulness and decreased total sleep in the daytime recording, and increased REM and decreased NREM sleep in both the day and night time recording. RGE ameliorated chronic stress and induced alterations of REM and NREM sleep in the day and night time sleep architecture. Acute and chronic stress could also induce alternations in cortex electroencephalogram (EEG) recording during NREM, REM sleep and wakefulness. These findings suggest that RGE may modulate the sleep behavior in acutely and chronically stressed rats and the ameliorating effect of RGE on the sleep architecture may involve in modulation of $\alpha$-, $\theta$- and $\delta$- wave activities of the cortical EEG.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.230-239
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• 2020

Previous studies have shown disrupted synaptic plasticity and neural activity in depression. Such alteration is strongly associated with disrupted synaptic structures. Chronic stress has been known to induce changes in dendritic structure in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), but antidepressant effect on structure of these brain areas has been unclear. Here, the effects of imipramine on dendritic spine density and morphology in BLA and mPFC subregions of stressed mice were examined. Chronic restraint stress caused depressive-like behaviors such as enhanced social avoidance and despair level coincident with differential changes in dendritic spine structure. Chronic stress enhanced dendritic spine density in the lateral nucleus of BLA with no significant change in the basal nucleus of BLA, and altered the proportion of stubby or mushroom spines in both subregions. Conversely, in the apical and basal mPFC, chronic stress caused a significant reduction in spine density. The proportion of stubby or mushroom spines in these subregions overall reduced while the proportion of thin spines increased after repeated stress. Interestingly, most of these structural alterations by chronic stress were reversed by imipramine. In addition, structural changes caused by stress and blocking the changes by imipramine were corelated well with altered activation and expression of synaptic plasticity-promoting molecules such as phospho-CREB, phospho-CAMKII, and PSD-95. Collectively, our data suggest that imipramine modulates stress-induced changes in synaptic structure and synaptic plasticity-promoting molecules in a coordinated manner although structural and molecular alterations induced by stress are distinct in the BLA and mPFC.

• Journal of Food Hygiene and Safety
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• v.5 no.4
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• pp.187-196
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• 1990

This study was carried out to develop new model for gastric ulcer and to investigate some factor which effect it. Rats were immersed for 8 hours. Ulcer index was measured from total length of occured ulcer. Ulcer index (UI) of restraint and immersion group was higher significantly than that of only restraint group (p<0.001) and ulcer was occurred within only glandular stomach. UI of low water temperature group was higher significantly than that of high water temperature group (p

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.3
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• pp.263-268
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• 2014

The etiology of most psychiatric disorders is still incompletely understood. However, growing evidence suggests that stress is a potent environmental risk factor for depression and anxiety. In rodents, various stress paradigms have been developed, but psychosocial stress paradigms have received more attention than non-social stress paradigms because psychosocial stress is more prevalent in humans. Interestingly, some recent studies suggest that chronic psychosocial stress and social isolation affects mainly anxiety-related behaviors in mice. However, it is unclear whether chronic non-social stress induces both depression- and anxiety-related phenotypes or induces one specific phenotype in mice. In the present study, we examined the behavioral consequences of three chronic non-social stress paradigms: chronic predictable (restraint) stress (CPS), chronic unpredictable stress (CUS), and repeated corticosterone-HBC complex injection (RCI). Each of the three paradigms induced mild to severe depression/despair-like behaviors in mice and resulted in increased immobility in a tail suspension test. However, anxiety-related phenotypes, thigmotaxis and explorative behaviors, were not changed by the three paradigms. These results suggest that depression- and anxiety-related phenotypes can be dissociated in mouse stress models and that social and non-social stressors might affect brain circuits and behaviors differently.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.2
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• pp.88-96
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• 2020

Stauntonia hexaphylla (SH) and Vaccinium bracteatum (VB) are herbal extracts widely used in food and traditional herbal medicine, and have the ability to perform a wide range of biological activities. We aimed to investigate the effects of the SH and VB combination (SHVB) on mice models of chronic restraint stress (CRS) and pentobarbital-induced sleeping behaviors to elucidate its possible mechanisms of action. CRS-exposed mice treated with SHVB showed significantly decreased immobility time, increased swimming and climbing times in the forced swim test (FST), and increased locomotor activity in the open field test (OFT). SHVB decreased serum CORT levels, but enhanced brain monoamine neurotransmitters. SHVB significantly decreased the sleep latency and increased total sleep duration in pentobarbital-induced sleeping behavior in mice. SHVB showed inhibitory effect on 5-HT_2A receptor-mediated ERK1/2 phosphorylation. These results suggest that SHVB has antidepressant and hypnotic effects by regulating the 5-HT_2A receptor.

• Journal of Ginseng Research
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• v.35 no.3
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• pp.331-338
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• 2011

Red ginseng (RG, the extract of Panax ginseng Meyer) has various biological and psychological activities and may also alleviate fatigue-related disorders. The present study was undertaken to evaluate what kind of fatigue red ginseng alleviate. Animals were orally administered with 50, 100, 200, 400 mg/kg of RG for 7 days. Before experiments were performed. Physiological stress (swimming, rotarod, and wire test) are behavioral parameters used to represent physical fatigue. Restraint stress and electric field test to a certain degree, induce psychological fatigue in animals. Plasma concentration of lactate and corticosterone (CORT) were also measured after these behavioral assays. RG supplementation (100 mg/kg) increased movement duration and rearing frequency of restrainted mice in comparison with control. 100 and 200 mg/kg of RG increased swimming time in cold water ($8{\pm}4^{\circ}C$) while at 100 mg/kg, RG increased electric field crossing over frequencies. 50, 100 and 200 mg/kg RG prolonged running time on the rotarod and at 100 mg/kg, it increased balancing time on the wire. RG at those doses also reduced falling frequencies. RG supplementation decreased plasma CORT levels, which was increased by stress. Lactate levels were not significantly altered. These results suggest that RG supplementation can alleviate more the damages induced by psychological than physical fatigue.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.61-61
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• 2010

The purpose of this study is to prevent the unstable fracture at the FCA butt weldment of hatch coaming deck in the ultra large containership during service life. In order to do it, the behavior of the embedded crack at the weldment under design loading conditions was evaluated in accordance with BS7910. Here, the level of primary stress induced by ship motion was evaluated by the design code of classification society and FEA. The level of residual stress as secondary stress was calculated in consideration of the restraint degree of weldment and welding heat input by using the predictive equation proposed by authors in the previous study. The fatigue crack growth rate at the weldment was evaluated using CT specimen in accordance with ASTM E647. According to the results, although the allowable defect for embedded crack specified in the classification society exists at the weldment, the occurrence possibility of unstable fracture at the weldment could not be negligible, regardless of CTOD value given in this study. So, in this study, the effect of initial defect size, welding heat input, restraint degree and CTOD on the fracture mechanical characteristics of embedded crack at the weldment was evaluated by the comprehensive fracture assessment. Based on the results, the design criteria including allowable defect, residual stress level and CTOD value was established to prevent the unstable fracture at the FCA butt weldment of hatch coaming deck in an ultra large containership during service life of 20years.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.37-42
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• 2007

The effects of immersion time in the liquid nitrogen and deformation-induced martensitic transformation on the behavior of austenite stainless steels used for the hydrogen storage tank of auto-mobile at cryogenic temperature were investigated. With increasing of immersion time in the liquid nitrogen, the tensile strength of all austenite stainless steels at cryogenic temperature was increased because the martensite transformation of unstable austenite. The restraint of crack generation ana transmission also increased the tensile strength by the active ${\alpha}'$ transformation. The elongation decreasing of 321 steel is not the mechanical deformation of austenite phase but the stress induced martensite phase during the tensile test.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1093-1098
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• 2007

In designing the high-speed railroad track, it is important to utilize appropriate track components to maintain uniform stiffness and ensure track alignment within the tolerance set for that system. In this regard, continuous welded rails (CWRs) were introduced to the Korean railways. Yet the installation of CWRs can result in an adverse impact due to the track/structure interaction on bridge sections yielding variations in the stiffness at the expansion joints. It may also impose additional axial force, generate excessive stress or deflection on track, and loosen the ballast at the ends as a bridge deck contracts or expands owing to a thermally-induced dynamic response. The risk is even greater in a long bridge deck, resulting in track longitudinal irregularities, deteriorating passenger's comfort, and increasing maintenance efforts. This study evaluates the performance of ZLR and their impact on track longitudinal irregularities through the track measuring results on a test section installed the ZLR in order to minimize the thermally-induced responses and the maintenance efforts for the high speed railway bridges.