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
