배양된 흰쥐 대뇌 피질 astrocytes의 세포기능에 대한 화학적 무산소증 유도물의 효과

Effects of Chemical Anoxia Inducers on Cellular Functions of Cultured Rat Cortical Astrocytes

The effects of antimycin A (AA), sodium azide (NaN3) and 2,4-dinitrophenol (DNP), which inhibit mitochondrial ATP production, on cellular functions of cultured astrocytes were studied. High concentrations of AA (50mcg/ml), NaN3 (100mM) and DNP (20mM) significantly decreased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction, which was known to be related to mitochondrial function and then cell viability. AA (50mcg/ml) increased lactate dehydrogenase (LDH) release and decreased [3H]glutamate uptake, suggesting severe damage of cellular function by the concentrations of the compounds. Meanwhile, low concentrations of AA (3(3H]glutamate uptake, indicating that these compounds increased MTT reduction at the low concentrations without cellular membrane damage. However, the low concentrations of AA produced significant decrease of MTT reduction in a glucose-free, medium. Low concentrations of AA (1 and 5mcg/ml) did not change ATP production of astrocytes in the medium containing 10mM glucose, but completely inhibited in a glucose-free medium, suggesting marked increase of cytosolic ATP production by the blockade of mitochondrial ATP production with low concentrations of AA. These results suggest that astrocytes have ability to enhance neuronal function or survival under conditions of incomplete ischemia or early stage of ischemia by enhancement of glycolysis, and that cellular reduction of MTT occurs not only mitochondrially but also extramitochondrially.