title: Inhibition of i-NOS but not n-NOS protects rat primary cell cultures against MPP(+)-induced neuronal toxicity.
abstract: Nitrative stress is a key component of the pathogenic process in Parkinson's disease (PD), but the relative roles of constitutive neuronal nitric oxide synthase (n-NOS) and inducible nitric oxide synthase (i-NOS) in glial cells remain unresolved. We have investigated the effects of a range of concentrations of the selective n-NOS inhibitor ARR17477, and the selective i-NOS inhibitor 1400W, on MPP(+)-induced cell death in foetal ventral mesencephalic (VM) dopaminergic cultures. MPP(+) induced a loss of TH-positive neurones accompanied by an increase in immunoreactivity for GFAP and OX-6 as markers of astrocytes and activated microglia, respectively, and induced i-NOS immunoreactivity. Unexpectedly, MPP(+) treatment did not induce 3-NT immunoreactivity in the cultures. ARR17477 and 1400W alone had no effect on the number of TH-positive cells or on the number of GFAP or OX-6 positive cells. ARR17477 did not prevent the MPP(+)-induced decrease in TH-positive neurones and had no effect on the increased number of GFAP- and OX-6-positive cells. By contrast, 1400W caused a concentration-dependent preservation of TH-positive neurones in the presence of MPP(+). It also significantly reduced the number of OX-6-immunoreactive cells and there was a small reduction in GFAP immunoreactivity. The results suggest a major role for i-NOS-mediated nitrative stress in microglia in MPP(+)-induced dopaminergic cell death and this may have important implications for developing neuroprotective strategies for PD.
authors.affiliation: Faculty of Life Sciences and Medicine, Neurodegenerative Diseases Research Group, Institute of Pharmaceutical Science, King's College London, London, UK.
authors.forename: Monika J
authors.initials: MJ
authors.lastname: Brzozowski
authors.forename: Peter
authors.initials: P
authors.lastname: Jenner
authors.forename: Sarah
authors.initials: S
authors.lastname: Rose
mesh_terms: D000578:Amidines / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D001596:Benzylamines / Q000494:pharmacology; D002452:Cell Count; D002478:Cells, Cultured; D059290:Dopaminergic Neurons / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D008636:Mesencephalon / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010300:Parkinson Disease / Q000188:drug therapy / Q000201:enzymology; D010847:Picolines / Q000633:toxicity*; D061251:Primary Cell Culture; D017208:Rats, Wistar; D013876:Thiophenes / Q000494:pharmacology; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D000578:Amidines; D000911:Antibodies, Monoclonal; D001596:Benzylamines; D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; C104820:N-(3-(aminomethyl)benzyl)acetamidine; C486880:N-(4-(2-((3-chlorophenylmethyl)amino)ethyl)phenyl)-2-thiophenecarboxamide; D018696:Neuroprotective Agents; C116337:OX-6 monoclonal antibody; D010847:Picolines; D013876:Thiophenes; C002744:3-nitrotyrosine; D014443:Tyrosine; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; D014446:Tyrosine 3-Monooxygenase; C515325:4-methylpyridine