title: Beta-adrenoceptor-mediated control of apical membrane conductive properties in fetal distal lung epithelia.
abstract: Distal lung epithelial cells isolated from fetal rats were cultured (48 h) on permeable supports so that transepithelial ion transport could be quantified electrometrically. Unstimulated cells generated a short-circuit current (I(sc)) that was inhibited (~80%) by apical amiloride. The current is thus due, predominantly, to the absorption of Na(+) from the apical solution. Isoprenaline increased the amiloride-sensitive I(sc) about twofold. Experiments in which apical membrane Na(+) currents were monitored in basolaterally permeabilized cells showed that this was accompanied by a rise in apical Na(+) conductance (G(Na(+))). Isoprenaline also increased apical Cl- conductance (G(Cl-)) by activating an anion channel species sensitive to glibenclamide but unaffected by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). The isoprenaline-evoked changes in G(Na(+)) and G(Cl(minus sign)) could account for the changes in I(sc) observed in intact cells. Glibenclamide had no effect upon the isoprenaline-evoked stimulation of I(sc) or G(Na(+)) demonstrating that the rise in G(Cl-) is not essential to the stimulation of Na(+) transport.
authors.affiliation: Lung Membrane Transport Group, Tayside Institute of Child Health, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK.
authors.forename: A
authors.initials: A
authors.lastname: Collett
authors.forename: S J
authors.initials: SJ
authors.lastname: Ramminger
authors.forename: R E
authors.initials: RE
authors.lastname: Olver
authors.forename: S M
authors.initials: SM
authors.lastname: Wilson
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D016764:Cell Polarity / Q000502:physiology; D002478:Cells, Cultured; D018118:Chloride Channels / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D015194:Diffusion Chambers, Culture; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D015633:Extravascular Lung Water / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000166:cytology; D005905:Glyburide / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism
chemical_list: D000318:Adrenergic beta-Agonists; D018118:Chloride Channels; D002712:Chlorides; D016895:Culture Media, Serum-Free; D007004:Hypoglycemic Agents; D011943:Receptors, Adrenergic, beta; D015222:Sodium Channels; D001464:Barium; D012964:Sodium; D007545:Isoproterenol; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D005905:Glyburide