INVESTIGADORES
PODEROSO Juan Jose
congresos y reuniones científicas
Título:
The biological purpose of nitric oxide synthase in mitochondria
Autor/es:
PODEROSO JJ
Lugar:
Buenos Aires
Reunión:
Congreso; XII Biennial Meeting of the Society for Free Radical Research International; 2004
Institución organizadora:
Society for Free Radical Research International
Resumen:
Mitochondria contain the central pathway for energy metabolism and participate in the production of O2 active species, cell cycle regulation, apoptosis and thermogenesis. Nitric oxide (NO) is identified as a physiologic regulator of O2 uptake and ATP synthesis by acting on cytochrome oxidase. Additionally, NO stimulates the mitochondrial production of O2 active species, which leads to formation of peroxynitrite and nitrosylation/nitration of mitochondria, the variations of mitochondrial nitric oxide synthase (mtNOS) have marked effects on O2 uptake, the production of O2 species and cell signaling. A marked increase of mtNOS content and activity provides a functional explanation for down-regulation of O2 uptake in hypothyroidism or in adaptation to prolonged cold environment. In accord to NO-redox effects, mtNOS is very low in embryos with high cell proliferation rate and low H2O2, and increases in the postnatal life associated to tissue quiescence with low proliferation rate and high H2O2. In addition to regulatory effects, constitutive NO production relates mitochondrial O2 uptake to O2 availability which are not interdependent up to hypoxic levels. Likely, mitochondrial NO acts as an antioxidant, protecting membranes from high oxidative non-modulated rates.