Absence of transepithelial anion exchange by rabbit OMCD: Evidence against reversal of cell polarity

Journal Article · Mon Aug 01 04:00:00 EDT 1988 · American Journal of Physiology; (USA)

OSTI ID:7191912

Hayashi, Matsuhiko; Schuster, V L; Stokes, J B ^[1]

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1. Univ. of Iowa College of Medicine, Iowa City (USA)

In the rabbit cortical collecting duct (CCD), Cl tracer crosses the epithelium predominantly via an anion exchange system that operates in either a Cl-Cl or Cl-HCO{sub 3} exchange mode. In the present study, the authors used the {sup 36}Cl lumen-to-bath rate coefficient (K{sub Cl}, nm/s), a sensitive measurement of CCD transepithelial anion transport, to investigate the nature of Cl transport in the medullary collecting duct dissected from inner stripe, outer medulla (OMCD). The K{sub Cl} in OMCD perfused and bathed in HCO{sub 3}-Ringer solution was low and similar to that value observed in the CCD when anion exchange is inhibited and Cl permeates the epithelium by diffusion. To test the hypothesis that metabolic alkalosis could reverse the polarity of intercalated cells and thus induce an apical Cl-HCO{sub 3} exchanger in H{sup +}-secreting OMCD cells, they measured K{sub Cl} in OMCD from rabbits make alkalotic by deoxycorticosterone and furosemide. Although the base-line K{sub Cl} was slightly higher than in OMCD from control rabbits, the value was still far lower than the K{sub Cl} under comparable conditions in CCD. They conclude (1) Cl transport across the MCD by anion exchange is immeasurably low or nonexistent; (2) unlike the CCD, Cl transport in OMCD is not responsive to cAMP; and (3) metabolic alkalosis does not induce an apical anion exchanger in OMCD, i.e., does not cause epithelial polarity reversal.

• OSTI ID: 7191912
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
ANIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CHARGED PARTICLES
CHLORINE 36
CHLORINE ISOTOPES
DIFFUSION
ELECTRON CAPTURE RADIOISOTOPES
EPITHELIUM
ION EXCHANGE
IONS
ISOTOPES
KIDNEYS
KINETICS
LIGHT NUCLEI
MAMMALS
MEMBRANE TRANSPORT
NUCLEI
ODD-ODD NUCLEI
ORGANS
PHYSIOLOGY
RABBITS
RADIOISOTOPES
REACTION KINETICS
TISSUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES