| Co-Investigator(Kenkyū-buntansha) |
SHIGEKI Imaizumi Tohoku University,School of Medicine, Assistant, 医学部, 助手 (30160039)
MASAKICHI Motomiya Tohoku University,Institute of Tuberculosis and camer, A.Professor, 抗酸菌病研究所, 助教授 (20006092)
FUMIO Inaba Tohoku University,Faculty of Engineering, Professor, 電気通信研究所, 教授 (90006213)
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| Research Abstract |
1; A spin trapping technique was applied to the detection of free radicals generated in NADPH-dependent lipid peroxidation of rat ischemic brain homogenate. The spin adduct of phenyl-t-butylnitrone (A_N = 16.2 - 16.5 G, A^H = 3.6 - 3.8 G) was observed, and it was thought to be derived from NADPH-dependent lipid peroxidation from its oxygen and NADPH dependency. Its intensity was increased in recirculated condition following ischemic insult, indicating the susceptibility of brain tissue to lipid peroxidation in such condition. And also, we gat the same result in the chemiluminescence (CL) determination of the ischemic brain. Through these experiments, we could elucidate that mannitol, vitamin E and glucocorticoid have benificial effects to scavange free radicals.
2; In the three vessel occlusion model, sharp decrease in the polyphospho-inositides were seen, after the start of ischemia. And they increased following recirculation. PPI metabolism had the reversibility in the temporary ischemia. The changes in PPI are thought to act as the trigger for ischemic conditions such as increase in intracellular Ca ions, activation of protein Kinase C, and release of free fatty acids (arachidonic acid). Moreover, the extremely rapid recovery of PPI following recirculation tells of the necessity of the preferential recovery of the cell function. In this experiment, phenytoin attenuated the increase of free fatty acid during ischemia, and promoted the recovery of energy metabolism following recirculation. Vitamin E also suppressed the increase of free fatty acids during ischemia.
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