Reduction of extracellular Na+ causes a release of Ca2+ from internal stores in airway epithelial cells

Scott Boitano, Michael L. Woodruff, Ellen R. Dirksen

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Exchange of physiological salt solution with Na+-free solution caused an increase in intracellular Ca2+ concentration ([Ca2+](i) in 86.3% of cultured airway epithelial cells within 75 s. [Ca2+](i) returned to near baseline levels within 45 s and frequently showed oscillatory increases thereafter. When extracellular Na+ concentration ([Na+](o)) was reduced to 10 and 60 mM, 59.0 and 8.0% of the cells increased [Ca2+](i), respectively. Low [Na+](o)-induced increase in [Ca2+](i) was not blocked by amiloride, benzamil, La3+, or the absence of extracellular Ca2+. Low [Na+](o)- induced [Ca2+](i) increase did not occur after thapsigargin treatment. These results indicated that low [Na+](o)-induced [Ca2+](i) increase is due to release of Ca2+ from intracellular stores. Because mechanical stimulation of a single cell causes a Ca2+ increase among many cells (Sanderson, M. J., A. C. Charles, and E. R. Dirksen. Mechanical stimulation and intercellular communication increases intracellular Ca2+ in epithelial cells. Cell Regul. 1: 585-596, 1990.) we assayed the effect of low [Na+](o) on this mechanically induced response. In low [Na+](o), mechanically induced [Ca2+](i) increase in the stimulated cell was reduced; however, [Ca2+](i) increase in adjacent cells was normal. We suggest that a mechanically induced Na+ conductance in the stimulated cell contributes to [Ca2+](i) changes. These signaling pathways may be involved in the maintenance of periciliary ion concentrations.

Original languageEnglish (US)
Pages (from-to)L1189-L1197
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number6 16-6
StatePublished - Jun 1997


  • Intracellular signaling
  • Salt regulation
  • Second messenger

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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