[Nitric oxide: a biological effector. Detection using electron paramagnetic resonance]

Nitric oxide is synthesized in mammalian cells from L-arginine or from pharmaceutical drugs. It forms paramagnetic complexes with some metalloproteins, including hemoglobin. Induction of NOSi following LPS or cytokine activation of murine macrophages has various effects, such as inhibition of mitochondrial respiration and that of DNA biosynthesis through interaction of NO with specific metalloenzymes. Induction of NOSi in a generator cell such as macrophage gives the same metabolic effects in target cells. NO is also detected in pathological states such as septic shock, diabetes mellitus and allograft, where the inducible L-arginine-NO pathway plays an important role. Electron Paramagnetic Resonance spectroscopy enables to detect unambiguously such specific molecular targets for NO in mammalian whole cells and organelles.