S-nitrosothiols and nitric oxide, but not sodium nitroprusside, protect nigrostriatal dopamine neurons against iron-induced oxidative stress in vivo.

Intranigral infusion of ferrous citrate (4.2 nmol) induced an acute lipid peroxidation in the substantia nigra and a chronic dopamine depletion in the striatum of rat nigrostriatal system. Coinfusion of 8.4 nmol nitric oxide donors such as S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylpenicillamine (SNAP) or nitric oxide (approximately 2 nmol) protected nigrostriatal neurons against iron-induced lipid peroxidation and associated oxidative injury. However, sodium nitroprusside (SNP, 8.4 nmol) augmented dopamine depletion caused by ferrous citrate because SNP is a ferricyanide complex. The present in vivo results indicate that nitric oxide and S-nitrosothiols are antioxidants which can protect brain dopamine neurons against oxidant stress/damage.