Stimulation of chloride transport by HCO/sub 3/-CO/sub 2/ in rabbit cortical collecting tubule
The authors examined both the role of HCO/sub 3/-CO/sub 2/ in Cl transport as well as the effect of in vivo acid-base status on Cl transport by the rabbit cortical collecting tubule. The lumen-to-bath /sup 36/Cl tracer flux, expressed as the rate coefficient K/sub Cl/, was measured in either HEPES-buffered (CO/sub 2/-free) or HCO/sub 3/-CO/sub 2/-containing solutions. Amiloride was added to the perfusate to minimize the transepithelial voltage and thus the electrical driving force for Cl diffusion. Because K/sub Cl/ fell spontaneously with time in HCO/sub 3/-CO/sub 2/ solutions in the absence but not the presence of cAMP, they used cAMP throughout to avoid time-dependent changes. Acute in vitro removal of bath HCO/sub 3/-CO/sub 2/ reduced K/sub Cl/. Acetazolamide addition in HEPES-buffered solutions also lowered K/sub Cl/; K/sub Cl/ could be restored to control values by adding exogenous HCO/sub 3/-CO/sub 2/ in the presence of acetazolamide. In vivo acid-base effects on Cl transport were determined by dissecting tubules from either NaHCO/sub 3/-loaded or NH/sub 4/Cl-loaded rabbits. Most of this effect of HCO/sub 3/-CO/sub 2/ addition on K/sub Cl/ could not be accounted for by Cl-HCO/sub 3/ exchange; rather, it appeared due to stimulation of Cl self exchange. The data are consistent with /sup 36/Cl transport occurring via Cl-HCO/sub 3/ exchange as well as Cl self exchange. Both processes are acutely stimulated by HCO/sub 3/ and/or CO/sub 2/, and both are chronically regulated by in vivo acid-base status.
- Research Organization:
- Univ. of Iowa, Iowa City
- OSTI ID:
- 6788348
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 251:1
- Country of Publication:
- United States
- Language:
- English
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CHLORINE 36
MEMBRANE TRANSPORT
TUBULES
ION EXCHANGE
CARBON DIOXIDE
CARBONATES
CHLORIDES
PHYSIOLOGY
RABBITS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HALIDES
HALOGEN COMPOUNDS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANS
OXIDES
OXYGEN COMPOUNDS
RADIOISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
551001* - Physiological Systems- Tracer Techniques