title: In vitro and in vivo evidences that antioxidant action contributes to the neuroprotective effects of the neuronal nitric oxide synthase and monoamine oxidase-B inhibitor, 7-nitroindazole.
abstract: The neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole (7-NI) is neuroprotective against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism. Monoamine oxidase (MAO)-B inhibitory action partially contributes to this effect. We tested the hypothesis that 7-NI could be a powerful hydroxyl radical (OH) scavenger, and interferes with oxidative stress caused by MPTP. We measured OH, reduced glutathione (GSH), as well as superoxide dismutase (SOD) and catalase activities in the nucleus caudatus putamen and substantia nigra of Balb/c mice following MPTP and/or 7-NI administration. The nNOS inhibitor caused dose-dependent inhibition in the production of OH in (i) Fenton-like reaction employing ferrous citrate in a cell-free system in test tubes, (ii) in isolated mitochondrial preparation in presence of MPP+, and (iii) in the striatum of mice systemically treated with MPTP. An MPTP-induced depletion of GSH in both the nuclei was blocked by 7-NI, which was dose-dependent (10-50mg/kg), but independent of MAO-B inhibition. The nNOS-mediated recovery of GSH paralleled attenuation of MPTP-induced depletion of striatal dopamine. MPTP-induced increase in the activities of striatal or nigral SOD and catalase were significantly attenuated by 7-NI treatment. These results suggest potent antioxidant action of 7-NI in its neuroprotective effects against MPTP-induced neurotoxicity.
authors.affiliation: Indian Institute of Chemical Biology, Division of Cell Biology & Physiology, Laboratory of Clinical & Experimental Neuroscience, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
authors.forename: Bobby
authors.initials: B
authors.lastname: Thomas
authors.forename: Karuppagounder S
authors.initials: KS
authors.lastname: Saravanan
authors.forename: Kochupurackal P
authors.initials: KP
authors.lastname: Mohanakumar
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001479:Basal Ganglia / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D002374:Catalase / Q000187:drug effects / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D007191:Indazoles / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008995:Monoamine Oxidase / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010088:Oxidoreductases / Q000494:pharmacology; D020734:Parkinsonian Disorders / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D007191:Indazoles; D018696:Neuroprotective Agents; D010088:Oxidoreductases; D002374:Catalase; D052248:Nitric Oxide Synthase Type I; D013482:Superoxide Dismutase; D008995:Monoamine Oxidase; C064258:free radical reductase; D005978:Glutathione; C080122:7-nitroindazole