Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Na+ channel activity in cultured renal (A6) epithelium: regulation by solution osmolarity.
Wills NK, Millinoff LP, Crowe WE.
???displayArticle.abstract???
Solution osmolarity is known to affect Na+ transport rates across tight epithelia but this variable has been relatively ignored in studies of cultured renal epithelia. Using electrophysiological methods to study A6 epithelial monolayers, we observed a marked effect of solution tonicity on amiloride-sensitive Na+ currents (I(sc)). I(sc) for tissues bathed in symmetrical hyposmotic (170 mOsm), isosmotic (200 mOsm), and hyperosmotic (230 or 290 mOsm) NaCl Ringer's solutions averaged 25 +/- 2, 9 +/- 2, 3 +/- 0.4, and 0.6 +/- 0.5 microA/cm2, respectively. Similar results were obtained following changes in the serosal tonicity: mucosal changes did not significantly affect I(sc). The changes in I(sc) were slow and reached steady-state within 30 min. Current fluctuation analysis measurements indicated that single-channel currents and Na+ channel blocker kinetics were similar for isosmotic and hyposmotic conditions. However, the number of conducting Na+ channels was approximately threefold higher for tissues bathed in hyposmotic solutions. No channel activity was detected during hyperosmotic conditions. The results suggest that Na+ channels in A6 epithelia are highly sensitive to relatively small changes in serosal solution tonicity. Consequently, osmotic effects may partly account for the large variability in Na+ transport rates for A6 epithelia reported in the literature.
Cantiello,
G protein subunit, alpha i-3, activates a pertussis toxin-sensitive Na+ channel from the epithelial cell line, A6.
1989, Pubmed
Cantiello,
G protein subunit, alpha i-3, activates a pertussis toxin-sensitive Na+ channel from the epithelial cell line, A6.
1989,
Pubmed Davis,
Interactions of sodium transport, cell volume, and calcium in frog urinary bladder.
1987,
Pubmed Diamond,
Transcellular cross-talk between epithelial cell membranes.
1982,
Pubmed Fidelman,
Insulin stimulation of Na+ transport and glucose metabolism in cultured kidney cells.
1982,
Pubmed Garty,
Guanosine nucleotide-dependent activation of the amiloride-blockable Na+ channel.
1989,
Pubmed Garty,
Direct inhibition of epithelial Na+ channels by a pH-dependent interaction with calcium, and by other divalent ions.
1987,
Pubmed Garty,
Ca2+-dependent, temperature-sensitive regulation of Na+ channels in tight epithelia. A study using membrane vesicles.
1985,
Pubmed Hazama,
Ca2+ sensitivity of volume-regulatory K+ and Cl- channels in cultured human epithelial cells.
1988,
Pubmed Helman,
Blocker-related changes of channel density. Analysis of a three-state model for apical Na channels of frog skin.
1990,
Pubmed Hoffmann,
Membrane mechanisms in volume and pH regulation in vertebrate cells.
1989,
Pubmed Keeler,
Evidence that prostaglandin E2 stimulates chloride secretion in cultured A6 renal epithelial cells.
1986,
Pubmed Krattenmacher,
Noise analysis of cAMP-stimulated Na current in frog colon.
1988,
Pubmed Lewis,
A reinvestigation of the function of the mammalian urinary bladder.
1977,
Pubmed Lewis,
Apical membrane area of rabbit urinary bladder increases by fusion of intracellular vesicles: an electrophysiological study.
1984,
Pubmed Mayer,
[Adaptation of Rana esculenta to various environments. A special study of renal excretion of water and electrolytes during changes in environment].
1969,
Pubmed Palmer,
Effects of cell Ca and pH on Na channels from rat cortical collecting tubule.
1987,
Pubmed Perkins,
Transport properties of toad kidney epithelia in culture.
1981,
Pubmed
,
Xenbase Sackin,
Stretch-activated potassium channels in renal proximal tubule.
1987,
Pubmed Sariban-Sohraby,
Phosphorylation of a single subunit of the epithelial Na+ channel protein following vasopressin treatment of A6 cells.
1988,
Pubmed Sariban-Sohraby,
Apical sodium uptake in toad kidney epithelial cell line A6.
1983,
Pubmed Sariban-Sohraby,
Methylation increases sodium transport into A6 apical membrane vesicles: possible mode of aldosterone action.
1984,
Pubmed Schultz,
Homocellular regulatory mechanisms in sodium-transporting epithelia: avoidance of extinction by "flush-through".
1981,
Pubmed Thomas,
Time-dependent apical membrane K+ and Na+ selectivity in cultured kidney cells.
1987,
Pubmed USSING,
RELATIONSHIP BETWEEN OSMOTIC REACTIONS AND ACTIVE SODIUM TRANSPORT IN THE FROG SKIN EPITHELIUM.
1965,
Pubmed Van Driessche,
Low-noise amplification of voltage and current fluctuations arising in epithelia.
1978,
Pubmed Van Driessche,
Spontaneous fluctuations of potassium channels in the apical membrane of frog skin.
1980,
Pubmed Wade,
ADH action: evidence for a membrane shuttle mechanism.
1981,
Pubmed Watson,
Accumulation of cAMP and calcium in S49 mouse lymphoma cells following hyposmotic swelling.
1989,
Pubmed Wills,
Recent advances in the characterization of epithelial ionic channels.
1987,
Pubmed Wills,
Active and passive properties of rabbit descending colon: a microelectrode and nystatin study.
1979,
Pubmed Wills,
Apical membrane properties and amiloride binding kinetics of the human descending colon.
1984,
Pubmed Wills,
Amiloride-sensitive Na+ transport across cultured renal (A6) epithelium: evidence for large currents and high Na:K selectivity.
1990,
Pubmed
,
Xenbase Wong,
Cell swelling increases intracellular free [Ca] in cultured toad bladder cells.
1990,
Pubmed
