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.
Amiloride-sensitive Na+ transport across cultured renal (A6) epithelium: evidence for large currents and high Na:K selectivity.
Wills NK
,
Millinoff LP
.
???displayArticle.abstract???
Electrical techniques were used to determine the Na:K selectivity of the amiloride-sensitive pathway and to characterize cellular and paracellular properties of A6 epithelium. Under control conditions, the mean transepithelial voltage (VT) was -57 +/- 5 mV, the short-circuit current (Isc) averaged 23 +/- 2 microA/cm2 and the transepithelial resistance (RT) was 2.8 +/- 0.3 k omega cm2 (n = 13). VT and Isc were larger than reported in previous studies and were increased by aldosterone. The conductance of the amiloride-sensitive pathway (Gamil) was assessed before and after replacement of Na+ in the mucosal bath by K+, using two independent measurements: (1) the slope conductance (GT), determined from current-voltage (I-V) relationships for control and amiloride-treated tissues and (2) the maximum amiloride-sensitive conductance (Gmax) calculated from the amiloride dose-response relationship. The ratio of Gamil in mucosal Na+ solutions to Gamil for mucosal K+ solutions was 22 +/- 6 for GT measurements and 15 +/- 2 for Gmax data. Serosal ion replacements in tissues treated with mucosal nystatin indicated a potassium conductance in the basolateral membrane. Equivalent circuit analyses of nystatin and amiloride data were used to resolve the cellular (Ec) and paracellular (Rj) resistances (approximately 5 k omega cm2 and 8-9 k omega cm2, respectively). Analysis of I-V relationships for tissues depolarized with serosal K+ solutions revealed that the amiloride-sensitive pathway could be described as a Na+ conductance with a permeability coefficient (PNa) = 1.5 +/- 0.2 x 10(-6) cm/s and the intracellular Na+ concentration (Nai) = 5 +/- 1 mM (n = 5), similar to values from other tight epithelia. We conclude that A6 epithelia are capable of expressing large amiloride-sensitive currents which are highly Na+ selective.
Benos,
Amiloride: a molecular probe of sodium transport in tissues and cells.
1982, Pubmed
Benos,
Amiloride: a molecular probe of sodium transport in tissues and cells.
1982,
Pubmed
Fidelman,
Insulin stimulation of Na+ transport and glucose metabolism in cultured kidney cells.
1982,
Pubmed
Fidelman,
Insulin and aldosterone interaction on NA+ and K+ transport in cultured kidney cells (A6).
1984,
Pubmed
Fidelman,
Network thermodynamic modeling of hormone regulation of active Na+ transport in cultured renal epithelium (A6).
1986,
Pubmed
Fidelman,
Effect of aldosterone and insulin on mannitol, Na+ and Cl- fluxes in cultured epithelia of renal origin (A6): evidence for increased permeability in the paracellular pathway.
1987,
Pubmed
Fuchs,
Current-voltage curve of sodium channels and concentration dependence of sodium permeability in frog skin.
1977,
Pubmed
Hamilton,
Regulation of single sodium channels in renal tissue: a role in sodium homeostasis.
1986,
Pubmed
Hamilton,
Single-channel recordings from amiloride-sensitive epithelial sodium channel.
1985,
Pubmed
,
Xenbase
Handler,
The effect of adrenal steroid hormones on epithelia formed in culture by A6 cells.
1981,
Pubmed
,
Xenbase
Handler,
Factors affecting the differentiation of epithelial transport and responsiveness to hormones.
1984,
Pubmed
Handler,
Transport in cultured epithelia.
1985,
Pubmed
,
Xenbase
Keeler,
Evidence that prostaglandin E2 stimulates chloride secretion in cultured A6 renal epithelial cells.
1986,
Pubmed
Kleyman,
The cellular pool of Na+ channels in the amphibian cell line A6 is not altered by mineralocorticoids. Analysis using a new photoactive amiloride analog in combination with anti-amiloride antibodies.
1989,
Pubmed
,
Xenbase
Lang,
Complete response to vasopressin requires epithelial organization in A6 cells in culture.
1986,
Pubmed
Lang,
Adenosine stimulates sodium transport in kidney A6 epithelia in culture.
1985,
Pubmed
,
Xenbase
Lewis,
Nystatin as a probe for investigating the electrical properties of a tight epithelium.
1977,
Pubmed
Lewis,
Urinary kallikrein: a physiological regulator of epithelial Na+ absorption.
1986,
Pubmed
Ling,
Effects of luminal Na+ on single Na+ channels in A6 cells, a regulatory role for protein kinase C.
1989,
Pubmed
Olans,
Saturation behavior of single, amiloride-sensitive Na+ channels in planar lipid bilayers.
1984,
Pubmed
,
Xenbase
Paccolat,
Aldosterone regulation of Na+ transport and Na+-K+-ATPase in A6 cells: role of growth conditions.
1987,
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
Sansom,
Mineralocorticoid regulation of apical cell membrane Na+ and K+ transport of the cortical collecting duct.
1985,
Pubmed
Sariban-Sohraby,
Apical sodium uptake in toad kidney epithelial cell line A6.
1983,
Pubmed
Sariban-Sohraby,
Amiloride-sensitive epithelial Na+ channels reconstituted into planar lipid bilayer membranes.
,
Pubmed
Thomas,
Time-dependent apical membrane K+ and Na+ selectivity in cultured kidney cells.
1987,
Pubmed
Thompson,
The electrophysiology of rabbit descending colon. I. Instantaneous transepithelial current-voltage relations and the current-voltage relations of the Na-entry mechanism.
1982,
Pubmed
Tousson,
Immunochemical localization of amiloride-sensitive sodium channels in sodium-transporting epithelia.
1989,
Pubmed
Wills,
Active and passive properties of rabbit descending colon: a microelectrode and nystatin study.
1979,
Pubmed
Wills,
Recent advances in the characterization of epithelial ionic channels.
1987,
Pubmed
Wills,
Transport-dependent alterations of membrane properties of mammalian colon measured using impedance analysis.
1987,
Pubmed
Wills,
Intracellular Na+ activity as a function of Na+ transport rate across a tight epithelium.
1980,
Pubmed
Yanase,
Adenosine 3',5'-cyclic monophosphate stimulates chloride secretion in A6 epithelia.
1986,
Pubmed
,
Xenbase
Yonath,
Determination of the driving force of the Na(+) pump in toad bladder by means of vasopressin.
1971,
Pubmed
