title: Amyloid-beta (25-35) increases activity of neuronal NO-synthase in rat brain.
abstract: Nitric oxide (NO) is a free radical with multiple functions in the nervous system. NO plays an important role in the mechanisms of neurodegenerative diseases including Alzheimer's disease. The main source of NO in the brain is an enzymatic activity of nitric oxide synthase (NOS). The aim of the present study was to analyze the expression and activity of both neuronal (nNOS) and inducible (iNOS) isoenzymes in the cerebral cortex and hippocampus of rats after intracerebroventricular administration of amyloid-beta (A beta) peptide fragment A beta(25-35). NADPHd histochemistry as well as immunohistochemistry were also used to investigate nNOS and iNOS expression in rat brain. The data presented here show that A beta(25-35) did not influence levels of nNOS or iNOS mRNA or protein expression in both structures studied. A beta(25-35) activated nNOS in the cerebral cortex and hippocampus without effect on iNOS activity. A beta(25-35) decreased the number of NADPHd-expressing neurons in the neocortex, but it did not significantly influence the number NADPHd-positive cells in the hippocampus. The peptide had no effect on the number of nNOS containing cells. We hypothesize that increased synthesis of NO induced by A beta(25-35) is related to qualitative alterations of nNOS molecule, but not to changes in NOS protein expression.
authors.affiliation: Institute of Higher Nervous Activity and Neurophysiology RAS, Butlerova 5A, Moscow 117485, Russia.
authors.forename: Mikhail Yu
authors.initials: MY
authors.lastname: Stepanichev
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Onufriev
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Yakovlev
authors.forename: Andrey I
authors.initials: AI
authors.lastname: Khrenov
authors.forename: Danil I
authors.initials: DI
authors.lastname: Peregud
authors.forename: Olga N
authors.initials: ON
authors.lastname: Vorontsova
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Lazareva
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Gulyaeva
mesh_terms: D000544:Alzheimer Disease / Q000201:enzymology* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000633:toxicity; D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000201:enzymology / Q000503:physiopathology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000201:enzymology / Q000503:physiopathology; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052248:Nitric Oxide Synthase Type I / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism* / Q000633:toxicity; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D012333:RNA, Messenger; C074636:amyloid beta-protein (25-35); D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II