Journal article
Fluid and electrolyte transport by cultured human airway epithelia
The Journal of clinical investigation, Vol.91(4), pp.1590-1597
04/1993
DOI: 10.1172/JCI116365
PMCID: PMC288135
PMID: 8473502
Abstract
An understanding of the fluid and electrolyte transport properties of any epithelium requires knowledge of the direction, rate, and regulation of fluid transport and the composition of the fluid. Although human airway epithelial likely play a key role in controlling the quantity and composition of the respiratory tract fluid, evidence for such a role is not available. To obtain such knowledge, we measured fluid and electrolyte transport by cultured human nasal epithelia. Under basal conditions we found that epithelia absorbed Na+ and fluid; both processes were inhibited by addition of amiloride to the mucosal surface. These data suggest that active Na+ absorption is responsible for fluid absorption. Interestingly, Na+ absorption was not accompanied by the net absorption of Cl-; some other anion accompanied Na+. The combination of cAMP agonists and mucosal amiloride stimulated the secretion of NaCl-rich fluid. But surprisingly, the response to cAMP agonists in the absence of amiloride showed substantial intersubject variability: cAMP stimulated fluid secretion across some epithelia, for others, cAMP stimulated fluid absorption. The explanation for the differences in response is uncertain, but we speculate that the magnitude of apical membrane Na+ conductance may modulate the direction of fluid transport in response to cAMP. We also found that airway epithelial secrete H+ and absorb K+ under basal conditions; both processes were inhibited by cAMP agonists. Because the H+/K(+)-ATPase inhibitor, SCH 28080, inhibited K+ absorption, an apical membrane H+/K(+)-ATPase may be at least partly responsible for K+ and H+ transport. However, H+/K+ exchange could not entirely account for the luminal acidification. The finding that cAMP agonists inhibited luminal acidification may be explained by the recent finding that cAMP increases apical HCO3- conductance. These results provide new insights into how the intact airway epithelium may modify the composition of the respiratory tract fluid.
Details
- Title: Subtitle
- Fluid and electrolyte transport by cultured human airway epithelia
- Creators
- J J Smith - Department of Pediatrics, Howard Hughes Medical Institute, University of Iowa College of Medicine, Iowa City 52242M J Welsh
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.91(4), pp.1590-1597
- Publisher
- United States
- DOI
- 10.1172/JCI116365
- PMID
- 8473502
- PMCID
- PMC288135
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Grant note
- HL42385 / NHLBI NIH HHS
- Language
- English
- Date published
- 04/1993
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Stead Family Department of Pediatrics; Fraternal Order of Eagles Diabetes Research Center; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020763102771
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