Nitric oxide mediates brain mitochondrial maturation immediately after birth

The possible role of nitric oxide ((NO)-N-.) in brain mitochondrial maturat ion was studied, Within the first 5 min after birth, a sharp increase in AT P concentrations was observed, coinciding with an increase in mitochondrial complex II-III (succinate-cytochrome c reductase) activity, while complex I (NADH-CoQ(1) reductase) and complex IV (cytochrome c oxidase) activities remained unchanged. Under the same circumstances, cGMP concentrations were increased by 5 min after birth, correlating significantly with ATP concentr ations. Since ATP concentrations also correlated significantly with mitocho ndrial complex ll-m activity, these three parameters may be associated, Inh ibition of (NO)-N-. synthase activity brought about by the administration o f NW-nitro-L-arginine monomethyl ester to mothers prevented the postnatal i ncrease in cGMP and ATP levels and complex II-III activity. These results s uggest that early postnatal mitochondrial maturation in the brain is a (NO) -N-.-mediated process. (C) 1999 Federation of European Biochemical Societie s.