Evidence against luminal one-for-one Cl -HCO3 exchange in urodele small intestine

Journal Article · Fri Aug 01 04:00:00 EDT 1986 · Am. J. Physiol.; (United States)

OSTI ID:6280938

White, J F

The ratio of Cl absorbed to HCO3 secreted by the in vitro small intestine of Amphiuma was measured using TWCl and titration. The aim was to estimate the stoichiometry and thereby elucidate the underlying transport mechanisms. For every mole of HCO3 secreted 1.8 mol of Cl underwent net absorption. Indirect measures of net Cl absorption and HCO3 secretion were validated. Several known and putative Cl transport inhibitors were examined for their ability to inhibit the anion transport events. Disulfonic stilbenes (DIDS) and the diuretics piretanide and furosemide inhibited the Cl absorptive flux (J/sub m s/sup Cl/) and simultaneously the HCO3 secretory flux (J/sup HCO3 /). The diuretics acetazolamide and bumetanide also reduced J/sup HCO3 and J/sub m s/sup Cl/, although the latter effect was not statistically significant. The ratio of inhibition, J/sub m s/sup Cl// J/sup HCO3 /, varied from 1.2 to 1.8 for the different inhibitors. The presence of Cl -HCO3 exchange at the serosal membrane was deduced from 1) the reduction of J/sub m s/sup Cl/ and J/sup HCO3 / by serosally added stilbenes, 2) the reduction of Cl absorption when serosal Cl was replaced, 3) inhibition of the secretory-to-mucosal Cl flux by serosal stilbenes, and 4) enhancement of J/sup HCO3 when serosal medium HCO3 was elevated. The observations are not consistent with one-for-one exchange of Cl for HCO3 at the mucosal membrane. The observed coupling ratio is compatible with a one-for-one exchange of Cl for HCO3 at the serosal membrane.

• Research Organization: Emory Univ. School of Medicine, Atlanta, GA
• OSTI ID: 6280938
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 251:2; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIONS
AQUATIC ORGANISMS
AROMATICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBON COMPOUNDS
CARBONIC ACID
CHARGED PARTICLES
CHLORINE
CHLORINE 36
CHLORINE ISOTOPES
COMPARTMENTS
DIGESTIVE SYSTEM
DIURETICS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
GASTROINTESTINAL TRACT
HALOGENS
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTESTINES
IONS
ISOTOPES
LIGHT NUCLEI
MEMBRANE TRANSPORT
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
RADIOISOTOPES
SMALL INTESTINE
STILBENE
STOICHIOMETRY
SULFONIC ACIDS
YEARS LIVING RADIOISOTOPES