Nitric-oxide-induced inhibition of mitochondrial complexes following aglycaemic hypoxia in neonatal cortical rat brain slices

The effect of aglycaemic hypoxia (AH) on the activity of the mitochondrial respiratory chain complexes was measured in superfused neonatal cortical br ain slices. After 30 min AH, there were no significant changes in the activ ities of complex 1, II-III and IV or citrate synthase compared to controls. Following 30 min AH and a 30-min reperfusion period (with oxygen and gluco se), the activities of complex II-III and complex IV were significantly red uced (by 25 and 17%, respectively). These reductions in enzyme activity wer e not abrogated by removing external calcium prior to and throughout AH, bu t could be reversed by the presence of the nitric oxide (NO) synthase inhib itor No-nitro-L-arginine during these periods. These data suggest that NO o r an NO-derived species is involved in the decreases in mitochondrial enzym e activities observed after AH Copyright (C) 2000 S. Karger AG,Basel.