Liquid transport properties of porcine tracheal epithelium.
Crews, Angela, Aubrey E. Taylor, and Stephen T. Ballard.
Department of Physiology, College of Medicine, University of South Alabama, Mobile, Alabama 36688
APStracts 8:0286A, 2001.
Because of its possible importance to the etiology of cystic fibrosis (CF) lung disease, the ion and water transport properties of tracheal epithelium were studied. Net liquid flux (JV) across porcine tracheal epithelium was measured in vitro using blue dextran as a volume probe. Luminal instillation of isosmotic sucrose solution (280 mM) induced a small net secretion of liquid (7.0 ± 1.7 nl•cm"minus"2•s"minus"1), whereas luminal hyposmotic sucrose solutions (220 or 100 mM) induced substantial and significant (P < 0.05) liquid absorption (34.5 ± 12 and 38.1 ± 7.3 nl•cm"minus"2•s"minus"1, respectively). When the luminal solution was normal (isosmotic) Krebs buffer, liquid was absorbed at 10.2 ± 1.1 nl•cm"minus"2•s"minus"1. Absorptive JV was abolished by 100 µM amiloride in the luminal solution and significantly reduced when the luminal solution was Na+-free Krebs solution. Absorptive JV was not significantly affected by 300 µM 5-nitro-2-(3-phenylpropylamino)benzoate or 100 µM diphenylamine-2-carboxylic acid, both CF transmembrane conductance regulator protein inhibitors, in the instillate but was significantly reduced by 60% when the luminal solution was Cl"minus"-free Krebs solution. We conclude that water freely permeates porcine tracheal epithelium and that absorption of liquid is normally driven by active transcellular Na+ transport and does not require the CF transmembrane conductance regulator protein.
Received 2 November 2000; accepted in final form 10 April 2001
APS Manuscript Number A1023-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001