| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Division of Pulmonary and Critical Care Medicine and Will Rogers Institute Pulmonary Research Center, University of Southern California, Keck School of Medicine, Los Angeles, California 90033
We
investigated acid-base permeability properties of electrically
resistive monolayers of alveolar epithelial cells (AEC) grown in
primary culture. AEC monolayers were grown on tissue culture-treated
polycarbonate filters. Filters were mounted in a partitioned cuvette
containing two fluid compartments (apical and basolateral) separated by
the adherent monolayer, cells were loaded with the pH-sensitive dye
2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and
intracellular pH was determined. Monolayers in
HCO
80% by 100 µM
dimethylamiloride, an inhibitor of Na+/H+
exchange, whereas acidification was not affected by a series of
acid/base transport inhibitors. Additional experiments in which AEC
monolayers were grown in the presence of acidic (6.4) or basic (8.0)
medium revealed differential effects on bioelectric properties depending on whether extracellular pH was altered in apical or basolateral fluid compartments bathing the cells. Acid exposure reduced
(and base exposure increased) short-circuit current from the
basolateral side; apical exposure did not affect short-circuit current
in either case. We conclude that AEC monolayers are relatively impermeable to transepithelial acid/base fluxes, primarily because of
impermeability of intercellular junctions and of the apical, rather
than basolateral, cell membrane. The principal basolateral acid exit
pathway observed under these experimental conditions is
Na+/H+ exchange, whereas proton uptake into
cells occurs across the basolateral cell membrane by a different,
undetermined mechanism. These results are consistent with the ability
of the alveolar epithelium to maintain an apical-to-basolateral (air
space-to-blood) pH gradient in situ.
alveolar epithelium; 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein; 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid; sodium/hydrogen exchange; acidosis
This article has been cited by other articles:
|
|
 |
|
  S. M. Caples, D. L. Rasmussen, W. Y. Lee, M. Z. Wolfert, and R. D. Hubmayr Impact of buffering hypercapnic acidosis on cell wounding in ventilator-injured rat lungs Am J Physiol Lung Cell Mol Physiol, January 1, 2009; 296(1): L140 - L144. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. H. Doerr, O. Gajic, J. C. Berrios, S. Caples, M. Abdel, J. F. Lymp, and R. D. Hubmayr Hypercapnic Acidosis Impairs Plasma Membrane Wound Resealing in Ventilator-injured Lungs Am. J. Respir. Crit. Care Med., June 15, 2005; 171(12): 1371 - 1377. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Murphy, V. V. Cherny, D. Morgan, and T. E. DeCoursey Voltage-gated proton channels help regulate pHi in rat alveolar epithelium Am J Physiol Lung Cell Mol Physiol, February 1, 2005; 288(2): L398 - L408. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Effros, L. Olson, W. Lin, S. Audi, G. Hogan, R. Shaker, K. Hoagland, and B. Foss Resistance of the pulmonary epithelium to movement of buffer ions Am J Physiol Lung Cell Mol Physiol, August 1, 2003; 285(2): L476 - L483. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. E. Decoursey Voltage-Gated Proton Channels and Other Proton Transfer Pathways Physiol Rev, April 1, 2003; 83(2): 475 - 579. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Matthay, H. G. Folkesson, and C. Clerici Lung Epithelial Fluid Transport and the Resolution of Pulmonary Edema Physiol Rev, July 1, 2002; 82(3): 569 - 600. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Matthay Editorial: Alveolar Epithelial Ion and Fluid Transport: Regulation of ion and fluid transport across the distal pulmonary epithelia: new insights Am J Physiol Lung Cell Mol Physiol, April 1, 2002; 282(4): L595 - L598. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
