Dependence of intracellular Na/sup +/ concentration on apical and basolateral membrane Na/sup +/ influx in frog skin
An isotopic method was developed to measure the intracellular Na/sup +/ content of the transepithelial Na/sup +/ transport pool of frog skin. Isolated epithelia (no corium) were labeled with /sup 24/Na either asymmetrically, from apical (Aa) or basolateral (Ab) solutions, or symmetrically (Aab). Transport pool Na/sup +/ could be identified from the kinetics of washout of /sup 24/Na carried out in the presence of 1 mM ouabain, 100 microM amiloride, and 1 mM furosemide that served to trap cold Na/sup +/ and /sup 24/Na within the transport pool. In control epithelia, Aab averaged 64.1 neq/cm/sup 2/ (13.9 mM), and maximal inhibition of apical membrane Na/sup +/ entry with 100 microM amiloride caused Aab to decrease to 24.3 neq/cm/sup 2/ (5.3 mM). Ouabain caused Aab to increase markedly to 303 neq/cm/sup 2/ in 30 min, whereas amiloride inhibition of apical membrane Na/sup +/ entry reduced markedly the rate of increase of Aab caused by ouabain. These data, in part, confirmed the existence of an important basolateral membrane permeability to Na/sup +/ that was measured in separate studies of the bidirectional /sup 24/Na fluxes at the basolateral membranes of the cells. Both sets of data were supportive of the idea that a significant Na/sup +/ recycling exists at the basolateral membranes of the cells that contributes to the Na/sup +/ load on the pump and Na/sup +/ recycling participates in the regulation of the Na/sup +/ concentration of the Na/sup +/ transport pool of these epithelial cells.
- Research Organization:
- Univ. of Illinois at Urbana-Champaign
- OSTI ID:
- 6036807
- Journal Information:
- Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States)
- Country of Publication:
- United States
- Language:
- English
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EPITHELIUM
KINETICS
SODIUM 24
MEMBRANE TRANSPORT
SODIUM COMPOUNDS
CATIONS
FROGS
OUABAIN
SKIN
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
AMPHIBIANS
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CHARGED PARTICLES
DRUGS
GLYCOSIDES
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SODIUM ISOTOPES
STROPHANTHINS
TISSUES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics