Department of Anesthesia Faculty Articles
PubMed Identifier
7304752
Bicarbonate Absorption by in Vitro Amphibian Small Intestine
Publication Title
American Journal of Physiology
Publisher
American Physiological Society
ISSN
0193-1857
Publication Date
11-1-1981
Keywords
Physiology
Abstract
Isolated segments of jejunum from Amphiuma bathed in Cl--free (SO42(-)) media usually generated serosa-negative electrical potentials when HCO3(-) was present in the media. Bidirectional isotope fluxes under short circuit revealed a negligible absorption of Na+ and a residual flux consistent with anion absorption. Acetazolamide (10(-4) M) eliminated the short-circuit current and the residual flux. Segments of jejunum exposed on the mucosal surface to HCO3(-) (pH 7.4) alkalinized the unbuffered serosal fluid at a rate of about 1.1 mueq . h-1 . cm-2, as measured by the pH-stat while clamped at zero transepithelial potential. Acetazolamide, anoxia, and 2,4-dinitrophenol lowered the rate of alkalinization and simultaneously reduced the short-circuit current by an equal amount. Absorption was constant above a [HCO3(-)] of 35 meq/l and uninfluenced by applied transepithelial voltage gradients. HCO3(-) absorption was not reduced after replacement of media Na+ or Cl- but was reduced on addition of ouabain or removal of K+. It is concluded that the jejunum actively absorbs HCO3(-) by an electrogenic process that does not involve Na+-H+ exchange.
DOI
https://doi-org/10.1152/ajpgi.1981.241.5.G389
Volume
241
Issue
5
First Page
G389
Last Page
G396
Funding Information
AM-00367/AM/NIADDK NIH HHS/United States AM-17361/AM/NIADDK NIH HHS/United States AM-26870/AM/NIADDK NIH HHS/United States
PubMed ID
7304752
Disciplines
Anesthesiology
NSUWorks Citation
White, John F. and Imon, Michael A., "Bicarbonate Absorption by in Vitro Amphibian Small Intestine" (1981). Department of Anesthesia Faculty Articles. 6.
https://nsuworks.nova.edu/hpd_anes_facarticles/6
