• Journal of fish pathology
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• v.4 no.2
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• pp.87-94
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• 1991

In the late summer of 1990 and 1991, mass mortality occured among cage-cultured grouper, Epinephelus septemfasciatus in south cost of Korea. The moribund fish didn't feed and became pale or dark chestnut colour and irregularly swimmed due to the loss of equilibrium, finally the diseased fish fell down side away on the bottom or the surface of cage showing the bent of body and died. The diseased fish showed the extensive hemorrahge in brain, the swelling of spleen and bile duct as the specific syptoms of internal organs. So the gill, skin and other organs of the diseased fish were examined for the presence of pathogenic parasites and bacteria. The parasitic Trichodina sp. were detected only from the gill lamella of the diseased fish, but these parasites seemed to be not a direct causative agents that induced the gross mortality of the cultured grouper. because these parasites were also observed in normal grouper, yellowtail, red seabream and rock bream co-cultured with the diseased grouper in same or near cages. In the viral examination, although isolation of the causative agent by the use of estabilshed cell Lines, RTG-2 and CHSE-214, was not succeed, the normal grouper inoculated intramuscularly with the filtered homogenate of the organs of the diseased fish showed the same external and internal signs with the naturally infected grouper. They died within a week. By using the naturally and the artificially infected fishes, electron microscopic observation revealed numerous hexagonal or polygonal particles in the cytoplasm of liver cells. Based on the these results, we suggest that the mass mortality of the cultured grouper would be occurred by the infection of a viral agent.

• The Korean Journal of Pharmacology
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• v.19 no.2
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• pp.57-67
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• 1983

The influence of electrolyte concentrations on the action of morphine and naloxone was studied in the myenteric plexus-longitudinal muscle preparation of guinea-pig ileum to examine whether opiate receptor binding obseved in vitro with homogenates represents binding to the pharmacological receptor. The preparations were suspended in a modified Krebs-Henseleit bicarbonate buffer solution and electrically stimulated at 0.2 Hz. Morphine inhibited electrically evoked contractions; the concentration of morphine required for a 50-percent inhibition was 190 nM. This inhibitory action of morphine was potentiated in a medium containing lower concentrations of : $Na^+\;or\;K^+$, or by the addition of $Mn^{2+}$ to the medium, and weakened by increasing the concentration of $Ca^{2+}$ or decreasing the concentration of $Mg^{2+}$. Naloxone antagonized these actions of morphine: however, $pA_2values$ for naloxone (indices of affinity for antagonists, approximately 8.8) were unaffected by these electrolyte concentrations. Thus, changes in the inhibitory action of morphine caused by alterations in electrolyte concentrations are probably not the result of changes in the affinity of the receptor for opiates, but due to alterations in the events which precede or follow the receptor binding. Effects of electrolytes on the affinity of the functional opiate receptor for naloxone in guinea-pig ileum are apparently different from those reported with the specific binding sites for opiates in brain homogenate.

• The Korean Journal of Pharmacology
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• v.20 no.2
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• pp.23-34
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• 1984

To investigate diurnal variations of opiate receptor binding and its modification by experimental condition or treatment of various centrally-acting drugs, the amount of maximum $^3H-morphine$ binding in rat midbrain homogenates was measured at 4 hour intervals for 24 hours. Animals were conditioned under the controlled L : D, 12 : 12 cycle or D: D, 12 : 12 cycle, for 3 weeks and treated with 0.5 ml of physiological saline or drugs for 2 weeks. A highly significant diurnal rhythm with peak at 22 hour of early dark phase with an amplitude$(0.68{\pm}0.06\;pmole/mg\;protein)$ of +51.1% and nadir $(0.33{\pm}0.03\;mole/mg\;prtein)$ at 18 hour of late light phase with an amplitude of -26.6% was found in control group. 24 tour mean of $^3H-morphine$ binding was $0.45{\pm}0.03\;pmole/mg$ protein respectively. Constant dark adaptation or treatment of reserpine, pargyline, imipramine, amphetamine and chlorpromazine modified the diurnal rhythm in the time of peak and nadir binding shape, phase, amplitude of the diurnal curve and 24 hour mean of $^3H-morphine$ binding. However, Kd values were not changed in all experimental groups : Statistical analysis at times of least and great binding indicates that the differences in $^3H-morphine$ binding were due to changes not in the affinity, but in the number of binding sites. The results are interpreted with regard to the diurnal rhythm of opiate receptor finding. The modes of action of psychoactive drugs are closely related to postulated changes of receptor sensitivity in neuropharmacological aspects.

• Food Science and Preservation
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• v.17 no.5
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• pp.720-726
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• 2010

The in vitro antioxidant activities and neuronal cell protective effects of 60% (w/v) methanolic extract from Houttuynia cordata were investigated. The contents of total phenolics and quercitrin in the extract were 17.71 mg/g and 75.80 ${\mu}g$/g, respectively. DPPH and ABTS radical-scavenging activities were 87.79% and 99.27%, respectively, when the extract was tested at 5 mg/ml. The FRAP (ferric reducing/antioxidant power) assay showed a dose-dependent increse in activity. In a cell viability assay using MTT, the extract protected against $H_2O_2$-induced neurotoxicity. Lactate dehydrogenase (LDH) leakage was also inhibited by the extract, as was lipid peroxidation as shown using the mouse brain homogenate test. These data indicate that a 60% (w/v) methanolic extract of Houttuynia cordata has in vitro antioxidant activities, and ingestion there of may reduce the risk of developing neurodegenerative disorders.