Co-Investigator(Kenkyū-buntansha) |
SANO Kemichi Institute of Community Medicine, Research Assistant, 社会医学系, 助手 (50098852)
KANO Katsumi Institute of Community Medicine, Associate Professor, 社会医学系, 助教授 (10101312)
SHIMOJO Nobuhiro Institute of Community Medicine, Associate Professor, 社会医学系, 助教授 (00080622)
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Research Abstract |
The results of the studies carried out for four years, 1985 to 1988, can be summarized as follows. 1) We have found the fact that the uptake of mercury compounds into the brain was increased by co-exsistence of amino acid and selenium compounds. Namely, after injection of mercury compounds, (methylmercury, ethylmercury and phenylmercury), with glutathione in the lateral ventricle, most of mercury compound flowed out into the blood, and then accumulated in various organs, especially in the brain. It was found that -GTP was concerned with the increase of mercury uptake. 2) We have studied the changes of locomoter activity and vital rhythm on mercury administered rat at the maximal non-toxic mercury levels. Locomoter activity of mercury administered rat was almost suppressed before two days of apperance of hind legs crossing. Locomoter activity of rat increased again, especially in the light time than the dark. We have noted, however, that the decrease of the 8-hr rhythm and increase of 3-h
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r rhythm, using the power spectrum analysis. But the rats which received mercury only did not show the changes in the circadium rhythm compaired with the rats which received mercury together with selenium. The similar results were obtained in the rats when maximal entropy analysis was employed. Therefore, it may be possible to be a criteria for the organic mercury toxicity. Inhibition of locomoter activity was evidently depended on the strength of mercury toxicity. Mercury levels in various regions of rat bfain was highest by ethylmercury injection and lowest by phenylmercury injection. 3) In spite of the injection of methylmercury at low concentration, we have demonstrated the influence on the neurotransmitter in the rat. On the first stage of methylmercury administration, mercury accumulated rapidly in the substantia nigra, but after onset of hind legs crossing, high concentration of mercury was found in cerebral cortex and striatum. On the other hand, catecholamine levels in these regions have decreased. 4) Cadmium binds to not only metallothionein but also to high molecular protein, mercaptalbumin in blood. Cadmium which bound mercaptalbumin flowed out to the blood serum and has inhibited the cholinesterase activity. This fact showed that the changes of cholinesterase activity may be pollible to differentiate the cadmium toxicity. Less
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