Contribution of amiloride-insensitive pathways to alveolar fluid clearance in adult rats

Andreas Norlin, Le Nha Lu, Sandra E. Guggino, Michael A. Matthay, Hans G. Folkesson

Research output: Contribution to journalArticle

Abstract

The contributions of amiloride-sensitive and -insensitive fractions of alveolar fluid clearance in adult ventilated rats were studied under control conditions and after β-adrenergic stimulation. Rats were instilled with a 5% albumin solution containing terbutaline (10-4 M) or dibutyryl-cGMP (DBcGMP; 10-4 M) with or without the cyclic nucleotide-gated cation channel inhibitor l-cis-diltiazem (10-3 M) and/or amiloride (10-3 M). Alveolar fluid clearance over i h was 18 ± 2% in controls. In controls, amiloride inhibited 46 ± 15% of alveolar fluid clearance, whereas l-cis-diltiazem had no inhibitory effect. Terbutaline and DBcGMP stimulated alveolar fluid clearance by 85 ± 3 and 36 ± 5%, respectively. Amiloride and l-cis-diltiazem inhibited nearly equal fractions of terbutaline-stimulated alveolar fluid clearance when given alone. Amiloride and l-cis-diltiazem given together inhibited a significantly larger fraction of alveolar fluid clearance in terbutaline-stimulated rats and in DBcGMP-stimulated rats. Based on these data, terbutaline stimulation recruited both amiloride-sensitive and l-cis-diltiazem-sensitive pathways. In contrast, DBcGMP mainly recruited l-cis-diltiazem-sensitive pathways. Therefore, the amiloride-insensitive fraction of Na+-driven alveolar fluid clearance may be partly mediated through cyclic nucleotide-gated cation channels and activated by an increase in intracellular cGMP.

Original languageEnglish (US)
Pages (from-to)1489-1496
Number of pages8
JournalJournal of applied physiology
Volume90
Issue number4
StatePublished - Mar 28 2001

Keywords

  • Cyclic nucleotide-gated cation channels
  • Dibutyryl-guanosine-3'5'-cyclic monophosphate
  • Epithelial sodium ion channels
  • Terbutaline
  • l-cis-diltiazem

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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  • Cite this

    Norlin, A., Lu, L. N., Guggino, S. E., Matthay, M. A., & Folkesson, H. G. (2001). Contribution of amiloride-insensitive pathways to alveolar fluid clearance in adult rats. Journal of applied physiology, 90(4), 1489-1496.