AJP - GI AJP: Gastrointestinal and Liver Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Gastrointest Liver Physiol 240: G472-G479, 1981;
0193-1857/81 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 Simson, J. N.
Right arrow Articles by Silen, W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Simson, J. N.
Right arrow Articles by Silen, W.

AJP - Gastrointestinal and Liver Physiology, Vol 240, Issue 6 472-G479, Copyright © 1981 by American Physiological Society

ARTICLES

Alkaline secretion by amphibian duodenum. II. Short-circuit current and Na+ and Cl- fluxes

J. N. Simson, A. Merhav and W. Silen

The relations among alkaline secretion, short-circuit current (Isc), and fluxes of Na+ and Cl- are examined. The Isc (1.15 +/- 0.03 microeq.cm-2.h-1) was significantly greater than the rate of alkaline secretion (1.02 +/- 0.02 microeq.cm-2.h-1). Regression analysis (n = 300) showed a highly significant correlation between alkaline secretion and Isc and indicated a residual Isc of 0.26 microeq.cm-2.h-1. In the absence of HCO3-, there was a residual Isc of 0.25 +/- 0.04 microeq.cm-2.h-1. This residual Isc is accounted for by an observed net Na+ absorption of 0.28 +/- 0.04 microeq.cm-2.h-1. Fluxes of Na+ fail to fit the flux-ratio equation and were not significantly affected by 2 X 10(-6) M ouabain, 5 X 10(-5) M amiloride, or anoxia but were significantly reduced by 2,4,6-triaminopyrimidine. The net Cl- flux was not significantly different from zero. Cl- fluxes conform to the flux-ratio equation and were reduced by anoxia or 2,4,6-triaminopyrimidine but were not affected by 4-acetamido-4'-isothiocynostilbene-2,2'-disulfonic acid (SITS). Anoxia or ouabain significantly inhibited alkaline secretion and Isc without affecting net fluxes of Na+ or Cl-, whereas amiloride or SITS had no effect on any of these parameters. There is no NaCl-coupled transport nor anion exchange, but solute-coupled Na+ absorption is demonstrated. We conclude that alkaline secretion by the duodenum involves a transcellular, energy-requiring, Na+-dependent, ouabain-sensitive, electrogenic mechanism that accounts for at least 80% of the Isc. Net Na+ absorption accounts for the residual Isc. Movements of Cl- are passive, do not contribute to Isc, and are not involved in the mechanism of alkaline secretion. Two hypothetical models of transcellular alkaline secretion are proposed.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
J. Praetorius, H. Hager, S. Nielsen, C. Aalkjaer, U. G. Friis, M. A. Ainsworth, and T. Johansen
Molecular and functional evidence for electrogenic and electroneutral Na+-HCO3{-} cotransporters in murine duodenum
Am J Physiol Gastrointest Liver Physiol, March 1, 2001; 280(3): G332 - G343.
[Abstract] [Full Text] [PDF]


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