title: The effect of brefeldin A on terbutaline-induced sodium absorption in fetal rat distal lung epithelium.
abstract: We studied the effect of brefeldin A, which inhibits the intracellular trafficking of membrane proteins from the cytosolic pool to the cell surface, on terbutaline (a beta2-specific adrenergic agonist)-induced alterations in ion transport by primary monolayer cultures of fetal rat distal lung epithelium. The amiloride-sensitive short circuit current (Isc) increased 2.5-fold 50 min after application of terbutaline (10 microM) from basolateral side; this response was abolished by pretreatment with brefeldin A (1 microg/ml). Brefeldin A did not suppress the Na+/K+ pump capacity. Single channel patch clamp experiments demonstrated that terbutaline increased the density of amiloride-sensitive Na+-permeable nonselective cation channels on the apical cell membrane and this action was blocked by brefeldin A. These observations suggest that beta2-specific adrenergic agonists promote the trafficking of amiloride sensitive Na+-permeable nonselective cation channels to the apical cell surface.
authors.affiliation: MRC Group in Lung Development and Division of Respiratory Research Hospital for Sick Children research Institute University of Toronto Faculty of Medicine Toronto, Ontario M5G 1X8, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: N
authors.initials: N
authors.lastname: Niisato
authors.forename: H
authors.initials: H
authors.lastname: O'Brodovich
authors.forename: Y
authors.initials: Y
authors.lastname: Marunaka
mesh_terms: D000042:Absorption / Q000187:drug effects; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D020126:Brefeldin A; D002412:Cations / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D004848:Epithelium / Q000196:embryology; D005333:Fetus / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D008168:Lung / Q000196:embryology*; D018408:Patch-Clamp Techniques; D051381:Rats / Q000196:embryology; D017208:Rats, Wistar; D012964:Sodium / Q000493:pharmacokinetics*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013726:Terbutaline / Q000494:pharmacology*
chemical_list: D002412:Cations; D003517:Cyclopentanes; D007473:Ion Channels; D020126:Brefeldin A; D000584:Amiloride; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D013726:Terbutaline