Modulation of lung liquid clearance by isoproterenol in rat lungs

F. Saldías, E. Lecuona, E. Friedman, M. L. Barnard, K. M. Ridge, J. I. Sznajder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

β-Adrenergic agonists have been reported to increase lung liquid clearance by stimulating active Na+ transport across the alveolar epithelium. We studied mechanisms by which β-adrenergic isoproterenol (Iso) increases lung liquid clearance in isolated perfused fluid-filled rat lungs. Iso perfused through the pulmonary circulation at concentrations of 10-4 to 10-8 M increased lung liquid clearance compared with that of control lungs (P < 0.01). The increase in lung liquid clearance was inhibited by the β- antagonist propranolol (10-5 M), the Na+-channel blocker amiloride (10- 4 M), and the antagonist of Na-K-ATPase, ouabain (5 x 10-4 M). Colchicine, which inhibits cell microtubular transport of ion-transporting proteins to the plasma membrane, blocked the stimulatory effects of Iso on active Na+ transport, whereas the isomer lumicolchicine, which does not affect cell microtubular transport, did not inhibit Na+ transport. In parallel with these changes, the Na-K-ATPase α1-subunit protein abundance and activity increased in alveolar type II cells stimulated by 10-6 M Iso. Colchicine blocked the stimulatory effect of Iso and the recruitment of Na-K-ATPase α1-protein to the basolateral membrane of alveolar type II cells. Accordingly, Iso increased active Na+ transport and lung liquid clearance by stimulation of β-adrenergic receptors and probably by upregulation of apical Na+ channels and basolateral Na-K-ATPase mechanisms. Recruitment from intracellular pools and microtubular transport of Na+ pumps to the plasma membrane participate in β-adrenergic stimulation of lung liquid clearance in rat lungs.

Original languageEnglish (US)
Pages (from-to)L694-L701
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume274
Issue number5 18-5
DOIs
StatePublished - May 1998

Keywords

  • Active sodium transport
  • Apical sodium channels
  • Cytoskeleton
  • Lung edema clearance
  • Sodium-potassium-adenosinetriphosphatase

ASJC Scopus subject areas

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

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