title: Epithelial Na+ channel and ion transport in human nasal polyp and paranasal sinus mucosa.
abstract: The purpose of the present study is to characterize the ENaC-mediated Na+ absorption in human upper airway epithelia, nasal cavity, and paranasal sinus. To perform the purpose, we obtained epithelial cells from human nasal polyp (NP) and paranasal sinus mucosa (PSM) by endoscopic surgery. We measured the short-circuit current (I(sc)) sensitive to benzamil (a specific ENaC blocker). The benzamil-sensitive I(sc) (Na+ absorption) in NP was larger than that in PSM. The mRNA expression of three subunits of ENaC was as follows: alpha>beta>gamma in both tissue, NP and MS. The mRNA expression of gamma subunit of ENaC in NP was larger than that in PSM, but no difference of mRNA expression of alpha or beta ENaC subunit between NP and PSM was detected. We found correlation of the Na+ absorption to mRNA expression of gamma ENaC in NP and PSM. Forskolin diminished the Na+ absorption associated with an increase in Cl- secretion. These observations suggest that: (1) human NP absorbs more ENaC-mediated Na+ than PSM, (2) expression of gamma ENaC in plays a key role in the ENaC-mediated Na+ absorption in NP and PSM, and (3) cAMP diminishes the ENaC-mediated Na+ absorption by stimulating Cl- secretion (diminution of driving force for Na+ absorption) in NP and PSM.
authors.affiliation: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yasuda
authors.forename: Naomi
authors.initials: N
authors.lastname: Niisato
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Takemitsu
authors.initials: T
authors.lastname: Hama
authors.forename: Kenji
authors.initials: K
authors.lastname: Dejima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hisa
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Marunaka
mesh_terms: D000042:Absorption; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D053503:Epithelial Sodium Channels / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D017136:Ion Transport; D007477:Ions; D008954:Models, Biological; D009092:Mucous Membrane / Q000378:metabolism*; D009298:Nasal Polyps / Q000473:pathology*; D010256:Paranasal Sinuses / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D012964:Sodium / Q000737:chemistry / Q000378:metabolism
chemical_list: D053503:Epithelial Sodium Channels; D007477:Ions; D012333:RNA, Messenger; C013407:benzamil; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000584:Amiloride; D012964:Sodium; D000242:Cyclic AMP