Augmentation of Endogenous Dopamine Production Increases Lung Liquid Clearance

Yochai Adir, Zaher S. Azzam, Emilia Lecuona, Sergio Leal, Liuska Pesce, Vidas Dumasius, Alejandro M. Bertorello, Phillip Factor, James B. Young, Karen M. Ridge, Jacob Iasha Sznajder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

We have previously reported that dopamine increased active Na+ transport in rat lungs by upregulating the alveolar epithelial Na,K-ATPase. Here we tested whether alveolar epithelial cells produce dopamine and whether increasing endogenous dopamine production by feeding rats a 4% tyrosine diet (TSD) would increase lung liquid clearance. Alveolar Type II cells express the enzyme aromatic-L-amino acid decarboxylase (AADC) and, when incubated with the dopamine precursor, 3-hydroxy-L-tyrosine (L-dopa), produce dopamine. Rats fed TSD, a precursor of L-dopa and dopamine, had increased urinary dopamine levels, which were inhibited by benserazide, an inhibitor of AADC. Rats fed TSD for 15, 24, and 48 hours had a 26, 46, and 45% increase in lung liquid clearance, respectively, as compared with controls. Also, dopaminergic D1 receptor antagonist - but not dopaminergic D2 receptor antagonist - inhibited the TSD-medlated increase in lung liquid clearance. Alveolar Type II cells isolated from the lungs of rats after they had been fed TSD for 24 hours demonstrated increased protein abundance of Na,K-ATPase α1 and β1 subunits. Basolateral membranes isolated from peripheral lung tissue of tyrosine-fed rats had increased Na,K-ATPase activity and Na,K-ATPase α1 subunit. These data provide the first evidence that alveolar epithelial cells produce dopamine and that increasing endogenous dopamine increases lung liquid clearance.

Original languageEnglish (US)
Pages (from-to)757-763
Number of pages7
JournalAmerican Journal of Respiratory and Critical Care Medicine
Volume169
Issue number6
StatePublished - Mar 15 2004

Keywords

  • Dopamine
  • Lung epithelium
  • Na,K-ATPase
  • Tyrosine diet

ASJC Scopus subject areas

  • Medicine(all)
  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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