title: Protective effect of histidine on para-nonylphenol-enhanced hydroxyl free radical generation induced by 1-methyl-4-phenylpyridinium ion (MPP+) in rat striatum.
abstract: The present study examined the antioxidant effect of histidine, a singlet oxygen ((1)O(2)) scavenger, on para-nonylphenol (an environmental estrogen-like chemical)-enhanced hydroxyl radical (.OH) generation induced by 1-methyl-4-phenylpyridinium ion (MPP+) in extracellular fluid of rat striatum. Rats were anesthetized, and sodium salicylate in Ringer's solution (0.5 nmol/microl/min) was infused through a microdialysis probe to detect the generation of.OH as reflected by the non-enzymatic formation of 2,3-dihydroxybenzoic acid (DHBA) in the striatum. Introduction of para-nonylphenol (10 microM) significantly enhanced MPP+ -induced.OH generation. Histidine (25 mM) decreased the para-nonylphenol-enhanced.OH formation. Although the level of MPP+ -induced.OH formation trapped as DHBA after para-nonylphenol treatment increased, para-nonylphenol failed to increase either the level of dopamine and DHBA formation in the reserpinized animals. These results indicate that para-nonylphenol and MPP+ -enhanced.OH generation was based on 1O(2) production, and histidine may have a preventive effect on para-nonylphenol and MPP+ -induced.OH generation in rat striatum.
authors.affiliation: Department of Pharmacology, Oita Medical University, 1-1, Hasama-machi, Oita 879-5593, Japan. tobata@oita-med.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Obata
authors.forename: S
authors.initials: S
authors.lastname: Kubota
authors.forename: Y
authors.initials: Y
authors.lastname: Yamanaka
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000037:antagonists & inhibitors*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000032:analysis / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D006639:Histidine / Q000494:pharmacology*; D062385:Hydroxybenzoates / Q000032:analysis / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D010636:Phenols / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012110:Reserpine
chemical_list: D005609:Free Radicals; D062385:Hydroxybenzoates; D010636:Phenols; D017665:Hydroxyl Radical; D006639:Histidine; C009135:2,3-dihydroxybenzoic acid; D012110:Reserpine; C041594:4-nonylphenol; D015655:1-Methyl-4-phenylpyridinium; D004298:Dopamine