title: A xanthine-based epithelium-dependent airway relaxant KMUP-3 (7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine) increases respiratory performance and protects against tumor necrosis factor-alpha-induced tracheal contraction, involving nitric oxide release and expression of cGMP and protein kinase G.
abstract: KMUP-3 (7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine) was investigated in guinea pig tracheal smooth muscle. Intratracheal instillation of tumor necrosis factor (TNF)-alpha (0.01 mg/kg/300 microl) induced bronchoconstriction, increases of lung resistance, and decreases of dynamic lung compliance. Instillation of KMUP-3 (0.5-2.0 mg/kg) reversed this situation. In isolated trachea precontracted with carbachol, KMUP-3 (10-100 microM)-caused relaxations were attenuated by epithelium removal and by pretreatments with an inhibitor of K(+) channel, tetraethylammonium (10 mm); K(ATP) channel, glibenclamide (1 microM); voltage-dependent K(+) channel, 4-aminopyridine (100 microM); Ca(2+)-dependent K(+) channel, charybdotoxin (0.1 microM) or apamin (1 microM); soluble guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1one (ODQ, 1 microM); nitric-oxide (NO) synthase, N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM); and adenylate cyclase, SQ 22536 [9-(terahydro-2-furanyl)-9H-purin-6-amine] (100 microM). KMUP-3 (0.01-100 microM) induced increases of cGMP and cAMP in primary culture of tracheal smooth muscle cells (TSMCs). The increase in cGMP by KMUP-3 was reduced by ODQ and L-NAME; the increase in cAMP was reduced by SQ 22536. Western blot analysis indicated that KMUP-3 (1 microM) induced expression of protein kinase A (PKA)(ri) and protein kinase G (PKG)(1alpha 1beta) in TSMCs.SQ 22536 inhibited KMUP-3-induced expression of (PKA)(ri). On the contrary, ODQ inhibited KMUP-3-induced expression of PKG(1alpha 1beta) In epithelium-intact trachea, KMUP-3 increased the NO release. Activation of sGC, NO release, and inhibition of phosphodiesterases in TSMCs by KMUP-3 may result in increases of intracellular cGMP and cAMP, which subsequently activate PKG and PKA, efflux of K(+) ion, and associated reduction in Ca(2+) influx in vitro, indicating the action mechanism to protect against TNF-alpha-induced airway dysfunction in vivo.
authors.affiliation: Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan.
authors.forename: Rong-Jyh
authors.initials: RJ
authors.lastname: Lin
authors.forename: Bin-Nan
authors.initials: BN
authors.lastname: Wu
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Lo
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: An
authors.forename: Zen-Kong
authors.initials: ZK
authors.lastname: Dai
authors.forename: Young-Tso
authors.initials: YT
authors.lastname: Lin
authors.forename: Chao-Shun
authors.initials: CS
authors.lastname: Tang
authors.forename: Ing-Jun
authors.initials: IJ
authors.lastname: Chen
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D006152:Cyclic GMP / Q000096:biosynthesis*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000096:biosynthesis*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology*; D015221:Potassium Channels / Q000378:metabolism; D012119:Respiration / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology*
chemical_list: C508169:7-(2-(4-(4-nitrobenzene)piperazinyl)ethyl)-1,3-dimethylxanthine; D010880:Piperidines; D015221:Potassium Channels; D014409:Tumor Necrosis Factor-alpha; D014970:Xanthines; D009569:Nitric Oxide; D017869:Cyclic GMP-Dependent Protein Kinases; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; D006152:Cyclic GMP