title: 7-nitroindazole protects striatal dopaminergic neurons against MPP+-induced degeneration: an in vivo microdialysis study.
abstract: The neuropathological hallmark of Parkinson's disease (PD) is the selective degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). In this study, using a microdialysis technique, we investigated whether an inhibitor of neuronal nitric oxide synthase (nNOS), 7-nitrindazole (7-NI), could protect against DAergic neuronal damage induced by in vivo infusion of 1-methyl-4-phenylpiridinium iodide (MPP(+)) in freely moving rats. Experiments were performed over 2 days in three groups of rats: (a) nonlesioned, (b) MPP(+)-lesioned, and (c) 7-NI pretreated MPP(+)-lesioned rats. On day 1, control rats were perfused with an artificial CSF, while 1 mM MPP(+) was infused into the striatum for 10 min in the other two groups. The infusion of the MPP(+) produced a neurotoxic damage of the SNc DA neurons and increased striatal DA levels. On day 2, 1 mM MPP(+) was reperfused for 10 min into the striata of each rat group and DA levels were measured as an index of neuronal cell integrity. The limited rise of DA following MPP(+) reperfusion in the MPP(+)-lesioned rats was due to toxin-induced neuronal loss and was reversed by pretreatment with 7-NI (50 mg/kg, intraperitoneally) on day 1, indicating a neuroprotective effect by inhibiting NO formation. These results indicate that neuronally derived NO partially mediates MPP(+)-induced neurotoxicity. The similarity between the MPP(+) model and PD suggests that NO may play a significant role in its etiology.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro (CH), Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Di Matteo
authors.forename: Arcangelo
authors.initials: A
authors.lastname: Benigno
authors.forename: Massimo
authors.initials: M
authors.lastname: Pierucci
authors.forename: Davide Antonio
authors.initials: DA
authors.lastname: Giuliano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Crescimanno
authors.forename: Ennio
authors.initials: E
authors.lastname: Esposito
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Di Giovanni
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000037:antagonists & inhibitors / Q000633:toxicity; D000818:Animals; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D009474:Neurons / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000502:physiology*; D010300:Parkinson Disease / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology
chemical_list: D004791:Enzyme Inhibitors; D007191:Indazoles; D018696:Neuroprotective Agents; D052248:Nitric Oxide Synthase Type I; D015655:1-Methyl-4-phenylpyridinium; C080122:7-nitroindazole; D004298:Dopamine