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.
Expression of epithelial Na channels in Xenopus oocytes.
Palmer LG, Corthesy-Theulaz I, Gaeggeler HP, Kraehenbuhl JP, Rossier B.
???displayArticle.abstract???
Epithelial Na channel activity was expressed in oocytes from Xenopus laevis after injection of mRNA from A6 cells, derived from Xenopus kidney. Poly A(+) RNA was extracted from confluent cell monolayers grown on either plastic or permeable supports. 1-50 ng RNA was injected into stage 5-6 oocytes. Na channel activity was assayed as amiloride-sensitive current (INa) under voltage-clamp conditions 1-3 d after injection. INa was not detectable in noninjected or water-injected oocytes. This amiloride-sensitive pathway induced by the mRNA had a number of characteristics in common with that in epithelial cells, including (a) high selectivity for Na over K, (b) high sensitivity to amiloride with an apparent K1 of approximately 100 nM, (c) saturation with respect to external Na with an apparent Km of approximately 10 mM, and (d) a time-dependent activation of current with hyperpolarization of the oocyte membrane. Expression of channel activity was temperature dependent, being slow at 19 degrees C but much more rapid at 25 degrees C. Fractionation of mRNA on a sucrose density gradient revealed that the species of RNA inducing channel activity had a sedimentation coefficient of approximately 17 S. Treatment of filter-grown cells with 300 nM aldosterone for 24 h increased Na transport in the A6 cells by up to fivefold but did not increase the ability of mRNA isolated from those cells to induce channel activity in oocytes. The apparent abundance of mRNA coding for channel activity was 10-fold less in cells grown on plastic than in those grown on filters, but was increased two- to threefold by aldosterone.
Asher,
Aldosterone increases the apical Na+ permeability of toad bladder by two different mechanisms.
1988, Pubmed
Asher,
Aldosterone increases the apical Na+ permeability of toad bladder by two different mechanisms.
1988,
Pubmed Benos,
The epithelial sodium channel. Subunit number and location of the amiloride binding site.
1987,
Pubmed Benos,
Amiloride: a molecular probe of sodium transport in tissues and cells.
1982,
Pubmed Dunn,
Low temperature selectively inhibits fusion between pinocytic vesicles and lysosomes during heterophagy of 125I-asialofetuin by the perfused rat liver.
1980,
Pubmed Eaton,
The amiloride-blockable sodium channel of epithelial tissue.
1988,
Pubmed Fambrough,
Biosynthesis and intracellular transport of acetylcholine receptors.
1983,
Pubmed Garty,
Amiloride-sensitive trypsinization of apical sodium channels. Analysis of hormonal regulation of sodium transport in toad bladder.
1983,
Pubmed Garty,
Mechanisms of aldosterone action in tight epithelia.
1986,
Pubmed Garty,
Sodium-dependent inhibition of the epithelial sodium channel by an arginyl-specific reagent.
1988,
Pubmed Garty,
Characteristics and regulatory mechanisms of the amiloride-blockable Na+ channel.
1988,
Pubmed Garty,
Ca2+-dependent, temperature-sensitive regulation of Na+ channels in tight epithelia. A study using membrane vesicles.
1985,
Pubmed Geering,
Receptor occupancy vs. induction of Na+-K+-ATPase and Na+ transport by aldosterone.
1985,
Pubmed Geering,
Membrane insertion of alpha- and beta-subunits of Na+,K+-ATPase.
1985,
Pubmed
,
Xenbase Geering,
Effects of thyromimetic drugs on aldosterone-dependent sodium transport in the toad bladder.
1984,
Pubmed George,
Functional expression of the amiloride-sensitive sodium channel in Xenopus oocytes.
1989,
Pubmed
,
Xenbase Gurdon,
Use of frog eggs and oocytes for the study of messenger RNA and its translation in living cells.
1971,
Pubmed
,
Xenbase Hamilton,
Single-channel recordings from amiloride-sensitive epithelial sodium channel.
1985,
Pubmed
,
Xenbase Hinton,
Expression of amiloride-blockable sodium channels in Xenopus oocytes.
1989,
Pubmed
,
Xenbase Hunt,
Control of haemoglobin synthesis: rate of translation of the messenger RNA for the alpha and beta chains.
1969,
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 Kroll,
Selective expression of an amiloride-inhibitable Na+ conductance from mRNA of respiratory epithelium in Xenopus laevis oocytes.
1989,
Pubmed
,
Xenbase 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,
Conductance and gating of epithelial Na channels from rat cortical collecting tubule. Effects of luminal Na and Li.
1988,
Pubmed Palmer,
Voltage-dependent block by amiloride and other monovalent cations of apical Na channels in the toad urinary bladder.
1984,
Pubmed Palmer,
Ion selectivity of epithelial Na channels.
1987,
Pubmed Palmer,
Stimulation of apical Na permeability and basolateral Na pump of toad urinary bladder by aldosterone.
1986,
Pubmed Palmer,
Activity coefficients of intracellular Na+ and K+ during development of frog oocytes.
1978,
Pubmed Perkins,
Transport properties of toad kidney epithelia in culture.
1981,
Pubmed
,
Xenbase 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 Spooner,
Further studies on the effect of aldosterone on electrical resistance of toad bladder.
1975,
Pubmed Truscello,
Effects of butyrate on histone deacetylation and aldosterone-dependent Na+ transport in the toad bladder.
1983,
Pubmed Van Driessche,
Concentration dependence of currents through single sodium-selective pores in frog skin.
1979,
Pubmed Warncke,
Voltage dependence of Na channel blockage by amiloride: relaxation effects in admittance spectra.
1985,
Pubmed Weigel,
Endocytosis and degradation mediated by the asialoglycoprotein receptor in isolated rat hepatocytes.
1982,
Pubmed
