Spreading depression and neuronal damage

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Two different sets of projects were performed.(1) Release and coversion of glutathione after global ischemia in ratA probe of microdialysis was implanted in the cerebral cortex and dialysate was collected continuously. Dialysate was analyzed for nitrite (NO2), nitrate (NO3), oxygenated glutathione(GSH) and reduced glutathione (GSSG) by using high performance liquid chromatography. Global ischemia was induced by ligation of both carotid arteries and hypotension. During reperfusion, oxygenated glutathione (GSH) increased simultaneously with GSSG.This release was terminated in 100 min after the start of reperfusion. NO2 and NO3 decreased during reperfusion and its profile was mirror image of GSH and GSSG.In conclusion, during early phase of reperfusion, reduced glutathione is rapidly synthetized and oxidized to GSH.This free radical trapping seems to contribute prevention of increase in nitrite and nitrate.(2) Mitochondrial membrane potential during reoxygenation after experimental ischemia in cultured neuronExperimental ischemia, no glucose and no oxygen, was induced in primary rat neuronal cell culture. Voltage sensitive dye, JC-1, was loaded to the neuronal culture and mitochondrial membrane potential was analysed by using Laser Scanning microscope. Wavelength of emitted light was 488nm and activated light of 530nm(represents depolarization) and 580nm(represents polarization) was analysed to determine mitochondrial membrane potential. After 30 min experimental ischemia, mitochondrial membrane was hyperpolarized, while, after 60 min experimental ischemia, mitochondria was depolarized. In conclusion, Mitochondrial membrane potential depends on rate of ATP production. Accompanying exclusion of proton from inner membrane during ATP production results in hyperpolarization. Hyperpolarization expressed by JC-1 after 30 min ischemia clearly reflects rapid production of ATP after ischemia.