Chloride and potassium channels in cystic fibrosis airway epithelia

Nature. 1986 Jul 31-Aug 6;322(6078):467-70. doi: 10.1038/322467a0.

Abstract

Cystic fibrosis, the most common lethal genetic disease in Caucasians, is characterized by a decreased permeability in sweat gland duct and airway epithelia. In sweat duct epithelium, a decreased Cl- permeability accounts for the abnormally increased salt content of sweat. In airway epithelia a decreased Cl- permeability, and possibly increased sodium absorption, may account for the abnormal respiratory tract fluid. The Cl- impermeability has been localized to the apical membrane of cystic fibrosis airway epithelial cells. The finding that hormonally regulated Cl- channels make the apical membrane Cl- permeable in normal airway epithelial cells suggested abnormal Cl- channel function in cystic fibrosis. Here we report that excised, cell-free patches of membrane from cystic fibrosis epithelial cells contain Cl- channels that have the same conductive properties as Cl- channels from normal cells. However, Cl- channels from cystic fibrosis cells did not open when they were attached to the cell. These findings suggest defective regulation of Cl- channels in cystic fibrosis epithelia; to begin to address this issue, we performed two studies. First, we found that isoprenaline, which stimulates Cl- secretion, increases cellular levels of cyclic AMP in a similar manner in cystic fibrosis and non-cystic fibrosis epithelial cells. Second, we show that adrenergic agonists open calcium-activated potassium channels, indirectly suggesting that calcium-dependent stimulus-response coupling is intact in cystic fibrosis. These data suggest defective regulation of Cl- channels at a site distal to cAMP accumulation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calcium / metabolism
  • Chlorides / metabolism*
  • Cyclic AMP / physiology
  • Cystic Fibrosis / metabolism*
  • Epithelium / metabolism
  • Humans
  • In Vitro Techniques
  • Ion Channels / physiology*
  • Permeability
  • Potassium / metabolism*
  • Sympathomimetics / pharmacology
  • Trachea / metabolism*

Substances

  • Chlorides
  • Ion Channels
  • Sympathomimetics
  • Cyclic AMP
  • Potassium
  • Calcium