title: L-NAME reverses quinolinic acid-induced toxicity in rat corticostriatal slices: Involvement of src family kinases.
abstract: Quinolinic acid (QA) is an endogenous excitotoxin acting on N-methyl-d-aspartate receptors (NMDARs) that leads to the pathologic and neurochemical features similar to those observed in Huntington's disease (HD). The mechanism of QA toxicity also involves free radicals formation and oxidative stress. NMDARs are particularly vulnerable to the action of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that can act as modulators of the activity of protein tyrosine kinases (PTKs) and phosphotyrosine phosphatases (PTPs). Because QA is able to activate neuronal nitric oxide synthase (nNOS) as well as to stimulate the NMDARs, we evaluated the effect of Nomega-Nitro-l-arginine-methyl ester (l-NAME), a selective nNOS inhibitor, on QA-induced neurotoxicity in rat corticostriatal slices. In electrophysiologic experiments we observed that slice perfusion with QA induced a strong reduction of field potential (FP) amplitude, followed by a partial recovery at the end of the QA washout. In the presence of l-NAME the recovery of FP amplitude was significantly increased with respect to QA alone. In synaptosomes, prepared from corticostriatal slices after the electrophysiologic recordings, we observed that l-NAME pre-incubation reversed the QA-mediated inhibitory effects on protein tyrosine phosphorylation pattern, c-src, lyn, and fyn kinase activities and tyrosine phosphorylation of NMDAR subunit NR2B, whereas the PTP activity was not recovered in the presence of l-NAME. These findings suggest that NO plays a key role in the molecular mechanisms of QA-mediated excitotoxicity in experimental model of HD.
authors.affiliation: Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena, Rome, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Mallozzi
authors.forename: Alberto
authors.initials: A
authors.lastname: Martire
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Domenici
authors.forename: Alessio
authors.initials: A
authors.lastname: Metere
authors.forename: Patrizia
authors.initials: P
authors.lastname: Popoli
authors.forename: A M Michela
authors.initials: AM
authors.lastname: Di Stasi
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000648:ultrastructure; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009498:Neurotoxins / Q000633:toxicity*; D019000:Phosphotyrosine / Q000378:metabolism; D017378:Quinolinic Acid / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013574:Synaptosomes / Q000187:drug effects; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D009498:Neurotoxins; D019000:Phosphotyrosine; D019061:src-Family Kinases; D017378:Quinolinic Acid; D019331:NG-Nitroarginine Methyl Ester