|
|
||||||||
Journal of Applied Physiology, Vol 69, Issue 2 523-531, Copyright © 1990 by American Physiological Society
ARTICLES |
E. M. Postlethwait, S. D. Langford and A. Bidani
Department of Internal Medicine, University of Texas Medical Branch, Galveston 77550.
In a previous study (J. Appl. Physiol. 68: 594-603, 1990) in isolated rat lungs, we suggested that the rate of pulmonary air space absorption of inhaled NO2 is limited, in part, by chemical reaction(s) rather than by physical solubility. Because the initial site of primary absorption interactions involves the epithelial lining fluid (ELF), we investigated whether ELF-NO2 interactions could account for pulmonary NO2 reactive absorption. Rat ELF, obtained by bronchoalveolar lavage (BAL), was compared with a model chemical system (reduced glutathione, GSH). In vitro exposures (NO2-air) used constant gas flow and planar gas-liquid interfaces. 1) Solvent pH notably altered NO2 uptake by GSH but to a lesser extent by BAL. 2) Uptake displayed [GSH]-dependent saturation. [ELF] in BAL was augmented by sequential lavage (lavagate reuse) of multiple lungs. Uptake was proportional to [ELF] but did not saturate under these exposure conditions. 3) The uptake rate exhibited [NO2] dependence. However, relative to increasing [NO2], fractional uptakes decreased for BAL and 1 mM GSH but not for 10 mM GSH. 4) Altered convective gas flow produced nonlinear increments in uptake (10 mM GSH) and substantial decrements in fractional uptake. 5) Arrhenius plots [ln(r) vs. 1/T, where r is reaction rate and T is absolute temperature (degree K)] for BAL and 1 mM GSH yielded respective activation energies of 4,952 and 4,149 kcal.g-1.mol-1 and degree of change in the rate of NO2 uptake per 10 degrees C (Q10) of 1.32 and 1.25. These results imply that the rate of NO2 uptake into rat ELF, like intact lung, is limited, in part, by chemical reaction(s).(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
![]() |
L. M. Connor, A. Bidani, J. Goerke, J. A. Clements, and E. M. Postlethwait NO2 interfacial transfer is reduced by phospholipid monolayers J Appl Physiol, November 1, 2001; 91(5): 2024 - 2034. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. W. Velsor and E. M. Postlethwait NO2-induced generation of extracellular reactive oxygen is mediated by epithelial lining layer antioxidants Am J Physiol Lung Cell Mol Physiol, December 1, 1997; 273(6): L1265 - L1275. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |