Journal of Applied Physiology Track the topics, authors and articles important to you
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 72: 2140-2148, 1992;
8750-7587/92 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Heming, T. A.
Right arrow Articles by Bidani, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Heming, T. A.
Right arrow Articles by Bidani, A.

Journal of Applied Physiology, Vol 72, Issue 6 2140-2148, Copyright © 1992 by American Physiological Society

ARTICLES

Influence of proton availability on intracapillary CO2-HCO3(-)-H+ reactions in isolated rat lungs

T. A. Heming and A. Bidani
Department of Internal Medicine, University of Texas Medical Branch, Galveston 77550.

Transcapillary CO2 exchange entails a transient perfusate CO2-HCO3(-)-H+ disequilibrium, leading to net loading or unloading of blood HCO3-. Perfusate reequilibration may or may not reach completion during the time of capillary transit, depending on the rate of intracapillary CO2-HCO3(-)-H+ reactions. Failure to reestablish equilibrium within the "open" capillary system leads to continued reequilibration in the "closed" postcapillary vasculature with resultant shifts in postcapillary perfusate PCO2, pH, and [HCO3-]. In the present study, we determined the effects of perfusate nonbicarbonate buffer capacity (beta) on intracapillary CO2-HCO3(-)-H+ reactions in isolated saline-perfused rat lungs. Effects of beta on the rate of transcapillary CO2 excretion (VCO2) and the magnitude of the postcapillary perfusate pH disequilibrium were measured as a function of luminal vascular carbonic anhydrase (CA) activity. The data indicate that beta markedly influenced the kinetics and dynamics of intravascular CO2-HCO3(-)-H+ reactions. beta affected VCO2 and the relative enhancement of VCO2 by luminal vascular CA. The data emphasize the inadequacies of using traditional "equilibrium" models of the CO2-HCO3(-)-H+ system to investigate capillary CO2 transport and exchange, even in organs (e.g., lungs) that contain significant luminal vascular CA activity.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
K. M. Gilmour and S. F. Perry
Branchial membrane-associated carbonic anhydrase activity maintains CO2 excretion in severely anemic dogfish
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2004; 286(6): R1138 - R1148.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
Y.-H. H. Lien and L.-W. Lai
Respiratory acidosis in carbonic anhydrase II-deficient mice
Am J Physiol Lung Cell Mol Physiol, February 1, 1998; 274(2): L301 - L304.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online