• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.66-66
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• 1999

The negative chronotropic effect of ACh on heart fades in the continuous presence of ACh, which is known as a phenomenon called "vagal escape". The underlying mechanism of vagal escape is not entirely clear, but desensitization of acetylcholine-activated $K^{＋}$ currents ($K_{ACh}$) was suggested, at least in part, to be responsible.(omitted)d)

• The Korean Journal of Zoology
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• v.12 no.2
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• pp.35-38
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• 1969

1. The sensibility of Fluta alba Zuiew to acetylcholine is more than ten times as strong as that of Ophicephalus argus Cantor which has been ever known as the most sensitive material. Fluta alba Zuiew is, therefore, considered as the best material for the bioassay of acetylcholine. 2. 5-hydorxytryptamine accelerates very much the heart activity of Misgurnus mizolepis Gunther but inhibits that of Fluta alba. 3. The sensibility of Fluta alba to norepinephrine is more than a hundred times as strong as that to epinephrine.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.155-163
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• 2003

Fluoranthene, a common polycyclicaromatic hydrocarbon (PAH), exhibits phototoxicity which may affect aquatic organisms. The eventual goal of this study is to develop a biomarker of Japanese medaka (Oryzias latipes) used in monitoring hazardous chemicals in the ecosystem. In this study we investigated neural toxicity of fluoranthene in Japanese medaka (Oryzias latipes) along with comparative analysis of corresponding behavioral response. The untreated individuals shooed normal behavioral characteristics (i. e., smooth and linear movements). The treated fish, however, showed stopping and abrupt change of orientation (100 ppb), and severely reduced locomotive activity and enhanced surfacing activity (1,000 ppb). Treatment of the medaka fish with fluoranthene caused a significant suppresson of acetycholine esterase (AChE) activities in the body portion but not in the head portion. When fish were exposed to 1,000 ppb of fluoranthene for 24 hr, the body AChE activities decreased from 126.${\pm}$31.89 (nmoles substrate hydrolyzed per min per mg protein) to 49.51${\pm}$11.99. Expressions of tyrosine hydroxylase (TH) protein in the different organs from both head and body portions were comparatively analyzed using an immunohistochemical technique. Five organs of the medaka fish showing a strong TH protein expression were the olfactory bulb, hypothalamus, optic lobe, pons and myelencephalon regions. This study provides molecular and neurobehavioral bases of a biomonitoring system for toxic chemicals using fish as a model organism.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.231-242
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• 1995

Electroconvulsive shock (ECS) increases the activity of acetylchohnesterase and decreases in brain acetylcholine levels. A large amount of free fatty acids accumulated in the brain tissue affects cerebral blood flow, brain edema and inflammation and results in brain injury. The present study examined the effect of docosahexaenoic acid (DHA) and D,L-pyroglutamic acid (D,L-PCA) on the learning and memory deficit using the passive avoidance failure technique and on the change of acetylcholine and choline level in the cerebral cortex of ECS-induced mice. The application of ECS (25mA, 0.5sec) induced a significant decrease in memory function for 30 min. ECS-induced a significant decrease in cortical acetylcholine and choline levels 1 min following the ECS application, which were almost recovered to ECS control level after 30 min. DHA (20 mg/kg, i.p.). administered 24 hr before shock. prevented the ECS-induced passive avoidance failure and the decrease of acetylcholine level 1 min following the ECS application. DHA failed to elicit a change in cortical choline level. DHA did not affect memory function and the cortical Ach and choline level of normal mice. The administration of D,L-PCA (500 mg/kg, i.p.) increased the effect of DHA on memory function and the change of cortical acetylcholine level of ECS induced mice. These results suggest that DHA treatment may be contributed to the prevention against memory deficit, and to the activation of cholinergic system in the ECS induced mice.

• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.392-395
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• 2005

A three-year old intact female German shepherd dog weighing 32kg was presented with the history of regurgitation and vomiting. Physical examination revealed a thin body condition, hoarse voice, hypersalivation, and pelvic limb weakness. In radiograph, meagaesophagus was identified. The neostigmine challenge test was positive. The titer of acetylcholine receptor (AChR) antibody was 1.58 nmol/L (reference range, <0.6nmol). Therefore, the dog was diagnosed to be suffering with chronic generalized form of acquired myasthenia gravis and followed by treatment with pyridostigmine bromide, 1mg/kg, q12 hrs. Treatment improved the pelvic limb weakness, however intermittent regurgitation and vomiting persisted. This resulted in aspiration pneumonia f3r which antibiotics were administered However, the dog was euthanized due to poor management and owner's request.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.127-131
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• 2007

The molecular design and holographic (H) quantitative structure-activity relationships (HQSARs) on the binding affinity constants between new 3-benzylidenemyosmine analogues and nicotin acetylcholine receptors (nAChRs) of American cockroach (Periplaneta. americana L.) were studied quantitatively. The optimized HQSAR model (IV-2) for the binding affinity constants was derived from fragment distinction of hydrogene atoms in fragment size, 5${\sim}$8 bin. The statistical results of the HQSAR model (IVI-2) exhibited the best predictability and fitness for the binding affinity constants based on the cross-validated value (q$^2$=0.507) and non cross-validated value (r$^2_{nev.}$=0.944). From the graphical analyses of atomic contribution maps, it was revealed that the binding affinity constants depends upon the anabaseine ring in molecule and the most active compounds were designed by optimized HQSAR model (VI-2).