Dobutamine Increases Alveolar Liquid Clearance in Ventilated Rats by beta-2 Receptor Stimulation

Am J Respir Crit Care Med. 1997 Aug;156(2 Pt 1):438-44. doi: 10.1164/ajrccm.156.2.9609141.

Abstract

Although it is well known that beta-adrenergic agonist stimulation increases alveolar epithelial sodium and fluid transport, it is not known whether the beta-1 or the beta-2 receptor mediates this effect. Two clinically relevant beta-adrenergic agonists, dopamine (beta-1 agonist) and dobutamine (beta-1 and beta-2 agonist) were used to define the contribution of these two beta-receptors to beta-adrenergic stimulated fluid clearance from the air spaces of the lungs. Alveolar fluid clearance was measured in anesthetized, ventilated rats over one hour after instilling an isosmolar 5% albumin solution in Ringer's lactate with 3 microCi 125I-albumin. The concentrations of the labeled and unlabeled albumin were used to quantify alveolar liquid clearance. Dopamine, whether given intra-alveolar (10(-4) M) or intravenously (5-10 micrograms/kg/min), had no effect. However, both intra-alveolar (10(-4) M) and intravenous (5 micrograms/kg/min) dobutamine increased alveolar liquid clearance by approximately 50% over one hour compared to controls. ICI 118,551, a potent and specific beta-2 antagonist, blocked the effect of dobutamine. The dobutamine effect was blocked by amiloride (10(-3) M), an inhibitor of sodium uptake. In summary, the beta-2 receptor mediates beta-adrenergic stimulation of alveolar epithelial sodium and fluid transport.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic beta-Agonists / administration & dosage
  • Adrenergic beta-Agonists / pharmacology*
  • Amiloride / administration & dosage
  • Amiloride / pharmacology
  • Animals
  • Dobutamine / administration & dosage
  • Dobutamine / antagonists & inhibitors
  • Dobutamine / pharmacology*
  • Dopamine / administration & dosage
  • Dopamine / pharmacology
  • Extravascular Lung Water / drug effects*
  • Extravascular Lung Water / physiology
  • Hemodynamics / drug effects
  • Male
  • Pulmonary Alveoli / drug effects*
  • Pulmonary Alveoli / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta-2 / drug effects*
  • Receptors, Adrenergic, beta-2 / physiology
  • Respiration, Artificial* / instrumentation
  • Respiration, Artificial* / methods
  • Stimulation, Chemical
  • Time Factors

Substances

  • Adrenergic beta-Agonists
  • Receptors, Adrenergic, beta-2
  • Dobutamine
  • Amiloride
  • Dopamine