Journal of Applied Physiology, Vol 55, Issue 6 1877-1883, Copyright © 1983 by American Physiological Society

ARTICLES

Characteristics of sodium transport by excised rabbit trachea

R. C. Boucher and J. T. Gatzy

We studied factors that might be expected to influence Na+ absorption, the major active ion transport by excised rabbit trachea. Transepithelial electric potential difference (PD), short-circuit current (Isc), conductance (G), and unidirectional 22Na+ and 36Cl- flows were measured before and during exposure to a drug or after a change in bathing solution composition. Ouabain (3 X 10(-4) M) in the submucosal bath abolished Isc and Na+ absorption but increased G and unidirectional Cl- flows. Luminal amiloride (10(-3) M) abolished net Na+ absorption but reduced Isc by only 40%. Residual Isc was accounted for by induction of net Cl- secretion, which resulted from a reduction in mucosal (m)-to-submucosal (s) Cl- flux (J). Replacement of luminal Na+ by choline induced effects similar to those of amiloride. Residual Isc was not reduced by mucosal indomethacin (10(-6) M). Replacement of luminal Cl- by gluconate raised transepithelial PD fourfold, raised Isc 50%, decreased G 60%, and abolished net Na+ absorption by decreasing Jm leads to s and increasing Js leads to m. Luminal amphotericin B affected bioelectric properties and ion flows minimally, whereas monensin (10(-4) M) decreased Isc and net Na+ transport. Antidiuretic hormone (ADH, 1 U/ml) or aldosterone (10(-6) M) did not affect in Isc or PD after exposure up to 6 h. We conclude that 1) Na+ absorption across the rabbit trachea is ouabain sensitive, 2) the entry step for Na+ across the luminal membrane is amiloride sensitive, 3) Cl- secretion induced by amiloride or luminal Na+ replacement probably reflects a more favorable chemical gradient for basolateral coupled NaCl entry and/or electrical gradient for Cl- efflux across the luminal membrane, 4) the coupling of Na+ entry to the presence of Cl- in the mucosal solution is probably an electrical rather than a chemical cotransport process, and 5) the tracheal epithelium of the rabbit is not a target for aldosterone and ADH.

This article has been cited by other articles:

				R. C. Dukarm, R. H. Steinhorn, J. A. Russell, S. Lakshminrusimha, D. Swartz, and J. J. Cummings Selective type 5 phosphodiesterase inhibition alters pulmonary hemodynamics and lung liquid production in near-term fetal lambs J Appl Physiol, December 1, 2005; 99(6): 2331 - 2336. [Abstract] [Full Text] [PDF]

				M. M. Cloutier, L. Guernsey, C. A. Wu, and R. S. Thrall Electrophysiological Properties of the Airway: Epithelium in the Murine, Ovalbumin Model of Allergic Airway Disease Am. J. Pathol., May 1, 2004; 164(5): 1849 - 1856. [Abstract] [Full Text] [PDF]

				A. Crews, A. E. Taylor, and S. T. Ballard Liquid transport properties of porcine tracheal epithelium J Appl Physiol, August 1, 2001; 91(2): 797 - 802. [Abstract] [Full Text] [PDF]

				J. J. Cummings and H. Wang Nitric oxide decreases lung liquid production via guanosine 3',5'-cyclic monophosphate Am J Physiol Lung Cell Mol Physiol, May 1, 2001; 280(5): L923 - L929. [Abstract] [Full Text] [PDF]

				B. R. Grubb and R. C. Boucher Effect of in vivo corticosteroids on Na+ transport across airway epithelia Am J Physiol Cell Physiol, July 1, 1998; 275(1): C303 - C308. [Abstract] [Full Text] [PDF]

				J. J. Cummings Nitric oxide decreases lung liquid production in fetal lambs J Appl Physiol, November 1, 1997; 83(5): 1538 - 1544. [Abstract] [Full Text] [PDF]