Acid secretion and proton conductance in human airway epithelium

Horst Fischer, Jonathan Widdicombe, Beate Illek

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Acid secretion and proton conductive pathways across primary human airway surface epithelial cultures were investigated with the pH stat method in Ussing chambers and by single cell patch clamping. Cultures showed a basal proton secretion of 0.1.7 ± 0.04 μmol·h-1·cm-2, and mucosal pH equilibrated at 6.85 ± 0.26. Addition of histamine or ATP to the mucosal medium increased proton secretion by 0.27 ± 0.09 and 0.24 ± 0.09 μmol·h-1·cm-2, respectively. Addition of mast cells to the mucosal medium of airway cultures similarly activated proton secretion. Stimulated proton secretion was similar in cultures bathed mucosally with either NaCl Ringer or ion-free mannitol solutions. Proton secretion was potently blocked by mucosal ZnCl2 and was unaffected by mucosal bafilomycin A1, Sch-28080, or ouabain. Mucosal amiloride blocked proton secretion in tissues that showed large amiloride-sensitive potentials. Proton secretion was sensitive to the application of transepithelial current and showed outward rectification. In whole cell patch-clamp recordings a strongly outward-rectifying, zinc-sensitive, depolarization-activated proton conductance was identified with an average chord conductance of 9.2 ± 3.8 pS/pF (at 0 mV and a pH 5.3-to-pH 7.3 gradient). We suggest that inflammatory processes activate proton secretion by the airway epithelium and acidify the airway surface liquid.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume282
Issue number4 51-4
StatePublished - 2002

Keywords

  • JME airway cells
  • Patch clamp
  • pH stat
  • Primary airway cultures
  • Ussing chamber

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

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