title: Distinct action of flavonoids, myricetin and quercetin, on epithelial Cl⁻ secretion: useful tools as regulators of Cl⁻ secretion.
abstract: Epithelial Cl(-) secretion plays important roles in water secretion preventing bacterial/viral infection and regulation of body fluid. We previously suggested that quercetin would be a useful compound for maintaining epithelial Cl(-) secretion at a moderate level irrespective of cAMP-induced stimulation. However, we need a compound that stimulates epithelial Cl(-) secretion even under cAMP-stimulated conditions, since in some cases epithelial Cl(-) secretion is not large enough even under cAMP-stimulated conditions. We demonstrated that quercetin and myricetin, flavonoids, stimulated epithelial Cl(-) secretion under basal conditions in epithelial A6 cells. We used forskolin, which activates adenylyl cyclase increasing cytosolic cAMP concentrations, to study the effects of quercetin and myricetin on cAMP-stimulated epithelial Cl(-) secretion. In the presence of forskolin, quercetin diminished epithelial Cl(-) secretion to a level similar to that with quercetin alone without forskolin. Conversely, myricetin further stimulated epithelial Cl(-) secretion even under forskolin-stimulated conditions. This suggests that the action of myricetin is via a cAMP-independent pathway. Therefore, myricetin may be a potentially useful compound to increase epithelial Cl(-) secretion under cAMP-stimulated conditions. In conclusion, myricetin would be a useful compound for prevention from bacterial/viral infection even under conditions that the amount of water secretion driven by cAMP-stimulated epithelial Cl(-) secretion is insufficient.
authors.affiliation: Department of Molecular Cell Physiology Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors.forename: Hongxin
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Molecular Cell Physiology Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan ; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Niisato
authors.affiliation: Department of Molecular Cell Physiology Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan ; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan ; Shin-Koiwa Clinic, Tokyo 124-0023, Japan.
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Nishio
authors.affiliation: Department of Physiology, School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Kirk L
authors.initials: KL
authors.lastname: Hamilton
authors.affiliation: Department of Molecular Cell Physiology Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan ; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan ; Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Marunaka
mesh_terms: D000818:Animals; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D015640:Ion Channel Gating / Q000187:drug effects; D009579:Nitrobenzoates / Q000378:metabolism; D011794:Quercetin / Q000737:chemistry / Q000494:pharmacology*; D014981:Xenopus
chemical_list: D002712:Chlorides; D005419:Flavonoids; D009579:Nitrobenzoates; D005576:Colforsin; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; C040015:myricetin; D011794:Quercetin