title: Involvement of sensory nerves and TRPV1 receptors in the rat airway inflammatory response to two environment pollutants: diesel exhaust particles (DEP) and 1,2-naphthoquinone (1,2-NQ).
abstract: The environmental chemical 1,2-naphthoquinone (1,2-NQ) is implicated in the exacerbation of airways diseases induced by exposure to diesel exhaust particles (DEP), which involves a neurogenic-mediated mechanism. Plasma extravasation in trachea, main bronchus and lung was measured as the local (125)I-bovine albumin accumulation. RT-PCR quantification of TRPV1 and tachykinin (NK(1) and NK(2)) receptor gene expression were investigated in main bronchus. Intratracheal injection of DEP (1 and 5 mg/kg) or 1,2-NQ (35 and 100 nmol/kg) caused oedema in trachea and bronchus. 1,2-NQ markedly increased the DEP-induced responses in the rat airways in an additive rather than synergistic manner. This effect that was significantly reduced by L-732,138, an NK(1) receptor antagonist, and in a lesser extent by SR48968, an NK(2) antagonist. Neonatal capsaicin treatment also markedly reduced DEP and 1,2-NQ-induced oedema. Exposure to pollutants increased the TRPV1, NK(1) and NK(2) receptors gene expression in bronchus, an effect was partially suppressed by capsaicin treatment. In conclusion, our results are consistent with the hypothesis that DEP-induced airways oedema is highly influenced by increased ambient levels of 1,2-NQ and takes place by neurogenic mechanisms involving up-regulation of TRPV1 and tachykinin receptors.
authors.affiliation: Department of Pharmacology, Institute of Biosciences (ICB-I), University of São Paulo (USP), São Paulo, SP 05508-900, Brazil. tmausp@yahoo.com
authors.forename: Soraia K P
authors.initials: SK
authors.lastname: Costa
authors.forename: Aila Mirtes
authors.initials: AM
authors.lastname: Teles
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Kumagai
authors.forename: Susan D
authors.initials: SD
authors.lastname: Brain
authors.forename: Simone A
authors.initials: SA
authors.lastname: Teixeira
authors.forename: Ana A
authors.initials: AA
authors.lastname: Varriano
authors.forename: Maria Alice A G
authors.initials: MA
authors.lastname: Barreto
authors.forename: Wothan Tavares
authors.initials: WT
authors.lastname: de Lima
authors.forename: Edson
authors.initials: E
authors.lastname: Antunes
authors.forename: Marcelo N
authors.initials: MN
authors.lastname: Muscará
authors.forename: Soraia K P
authors.initials: SK
authors.lastname: Costa
mesh_terms: D000393:Air Pollutants / Q000633:toxicity; D000818:Animals; D005260:Female; D007249:Inflammation / Q000378:metabolism; D008297:Male; D009285:Naphthoquinones / Q000633:toxicity*; D009475:Neurons, Afferent / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012137:Respiratory System / Q000187:drug effects* / Q000294:innervation / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism*; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D009285:Naphthoquinones; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; D001335:Vehicle Emissions; C040756:1,2-naphthoquinone