Department of Anesthesia Faculty Articles
Title
Bicarbonate absorption by in vitro amphibian small intestine
ISBN or ISSN
0002-9513
Publication Title
The American journal of physiology
Volume
241
Issue
5
Publication Date / Copyright Date
11-1-1981
First Page
389
Last Page
396
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.
Disciplines
Anesthesiology
Keywords
Physiology
NSUWorks Citation
White, J F. and Imon, Michael, "Bicarbonate absorption by in vitro amphibian small intestine" (1981). Department of Anesthesia Faculty Articles. 6.
https://nsuworks.nova.edu/hpd_anes_facarticles/6
