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Oxygen-evoked Na+ transport in rat fetal distal lung epithelial cells.
- Source :
-
The Journal of physiology [J Physiol] 2001 Apr 01; Vol. 532 (Pt 1), pp. 105-13. - Publication Year :
- 2001
-
Abstract
- Monolayer cultures of rat fetal distal lung epithelial (FDLE) cells generated larger spontaneous short circuit currents (ISC) when maintained (48 h) at neonatal alveolar PO2 (100 mmHg) than at fetal PO2 (23 mmHg). When cells were shifted between these atmospheres in order to impose a rise in PO2 equivalent to that seen at birth, no rise in ISC was seen after 6 h but the response was fully established by 24 h. Studies of basolaterally permeabilised cells revealed a small rise in apical Na+ conductance (GNa) 6 h after PO2 was raised but no further change had occurred by 24 h. A substantial rise was, however, seen after 48 h. Reporter gene assays showed that no activation of the -ENaC (epithelial Na+ channel -subunit) promoter was discernible 24 h after PO2 was raised but increased transcriptional activity was seen at 48 h. Studies of apically permeabilised cells showed that a small rise in Na+ pump capacity was evident 6 h after PO2 was raised and, in common with the rise in ISC, this effect was fully established by 24 h. The rise in ISC thus develops 6-24 h after PO2 is raised and is due, primarily, to increased Na+ pump capacity. The increase in GNa thus coincides with activation of the -ENaC promoter but these effects occur after the rise in ISC is fully established and so cannot underlie this physiological response. The increased transcription may be an adaptation to increased Na+ transport and not its cause.
- Subjects :
- Amiloride pharmacology
Animals
Cell Polarity
Cells, Cultured
Genes, Reporter
Ion Transport
Lung cytology
Lung embryology
Membrane Potentials physiology
NF-kappa B metabolism
Promoter Regions, Genetic
Protein Subunits
Rats
Rats, Sprague-Dawley
Sodium Channels genetics
Sodium-Potassium-Exchanging ATPase genetics
Time Factors
Transcription, Genetic
Epithelial Cells metabolism
Lung metabolism
Oxygen metabolism
Sodium metabolism
Sodium Channels metabolism
Sodium-Potassium-Exchanging ATPase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3751
- Volume :
- 532
- Issue :
- Pt 1
- Database :
- MEDLINE
- Journal :
- The Journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 11283228
- Full Text :
- https://doi.org/10.1111/j.1469-7793.2001.0105g.x