title: MPP+ induced substantia nigra degeneration is attenuated in nNOS knockout mice.
abstract: Recent studies showed that neuronal nitric oxide synthase (nNOS) plays a role in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity. In the present study we examined the effects of striatal injection of 1-methyl-4-phenylpyridinium (MPP+) on substantia nigra degeneration in mutant mice lacking the nNOS gene or the endothelial nitric oxide synthase (eNOS) gene. Both striatal lesion volume and substantia nigra degeneration were significantly attenuated in the nNOS mutant mice but not in the eNOS mutant mice. The mice lacking nNOS showed a significant attenuation of MPP+(-) induced increases of 3-nitrotyrosine concentrations in the striatum. In a separate experiment administration of 7-nitroindazole for 48 h after MPP+ injections significantly attenuated substantia nigra degeneration in rats. Immunohistochemical studies showed apposition of nNOS-positive neuronal processes on tyrosine hydroxylase-positive neurons. These results provide further evidence that neuronally derived NO and peroxynitrite play a role in MPP+ neurotoxicity.
authors.affiliation: Neurochemistry Laboratory, Massachusetts General Hospital, Boston, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Matthews
authors.forename: M F
authors.initials: MF
authors.lastname: Beal
authors.forename: J
authors.initials: J
authors.lastname: Fallon
authors.forename: K
authors.initials: K
authors.lastname: Fedorchak
authors.forename: P L
authors.initials: PL
authors.lastname: Huang
authors.forename: M C
authors.initials: MC
authors.lastname: Fishman
authors.forename: B T
authors.initials: BT
authors.lastname: Hyman
mesh_terms: D015655:1-Methyl-4-phenylpyridinium; D000818:Animals; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009410:Nerve Degeneration / Q000139:chemically induced* / Q000235:genetics; D009474:Neurons / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000187:drug effects* / Q000473:pathology
chemical_list: D019001:Nitric Oxide Synthase; D015655:1-Methyl-4-phenylpyridinium