The formation of reactive oxygen species in a fraction of rat brain by metabolism of nitric oxide.

The potential of nitric oxide for the induction of reactive oxygen species (ROS) has been evaluated in a cerebral synaptosomal fraction. Nitric oxide (NO) was generated using S-nitroso-N-acetylpenicillamine (SNAP). NO stimulated ROS production, assayed using a fluorescent probe. This stimulation was largely inhibited by superoxide dismutase but not by catalase, implying that superoxide anion but not hydrogen peroxide, was a critical intermediate. An iron chelator, deferoxamine or hydroxyl radical scavengers failed to prevent stimulation of ROS by SNAP. This suggests the possibility of formation of a novel class of short-lived active oxygen species by NO.