Niflumic and flufenamic acids are potent inhibitors of chloride secretion in mammalian airway

Life Sci. 1992;51(18):1453-7. doi: 10.1016/0024-3205(92)90540-6.


Effects of niflumic acid (NFA) and flufenamic acid (FFA), the two nonsteroid anti-inflammatory agents recently reported to inhibit Cl- current in Xenopus oocytes, were examined in cultured monolayers of dog and cow trachea. Both agents showed potent inhibition to the short-circuit current (Isc), an index of magnitude of transepithelial Cl- secretion, with values of Ki of 0.02 (for NFA) and 0.06 (for FFA) mM, respectively. The sensitivity sequence of Isc to the Cl- channel inhibitors tested was NFA > FFA > diphenylamine-2-carboxylate (DPC) >> anthracene-9-carboxylate (A9C). Thus, NFA and FFA are so far the most potent commercially available Cl- channel inhibitors tested in Cl(-)-secreting epithelia. The sensitivity sequence of 36Cl uptake to the above Cl- channel inhibitors in Xenopus laevis oocytes was found to be identical to the cultures of trachea. This seems to imply that the membrane Cl- channels of Xenopus oocytes are functionally similar to that identified in mammalian Cl(-)-secreting epithelia.

Publication types

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

MeSH terms

  • Animals
  • Cattle
  • Cells, Cultured
  • Chloride Channels
  • Chlorides / metabolism*
  • Dogs
  • Epithelial Cells
  • Epithelium / metabolism
  • Flufenamic Acid / pharmacology*
  • Ion Channels / drug effects*
  • Membrane Proteins / antagonists & inhibitors*
  • Niflumic Acid / pharmacology*
  • Oocytes / metabolism
  • Trachea / drug effects*
  • Trachea / metabolism
  • Xenopus laevis


  • Chloride Channels
  • Chlorides
  • Ion Channels
  • Membrane Proteins
  • Niflumic Acid
  • Flufenamic Acid