Differential effects of furosemide on porcine bronchial arterial and airway smooth muscle

J Appl Physiol (1985). 2000 Oct;89(4):1360-4. doi: 10.1152/jappl.2000.89.4.1360.


Furosemide attenuates airway obstruction in asthmatic subjects when administered as an aerosol pretreatment. This protective effect of furosemide could be related to relaxation of bronchial smooth muscle or to increased bronchial blood flow. To determine whether furosemide dilates bronchial smooth muscle, isometric contractile responses in distal bronchi from young pigs were studied. In bronchial smooth muscle rings that were precontracted with 10(-5) M acetylcholine, significant relaxation occurred with 10(-8) to 3 x 10(-6) M isoproterenol but not with 10(-8) to 10(-3) M furosemide. In contrast, bronchial arteries that were precontracted with either 10(-4) M norepinephrine or 10(-8) M vasopressin significantly relaxed in response to 10(-4) to 3 x 10(-3) M and 10(-3) to 3 x 10(-3) M furosemide, respectively. We conclude that furosemide, under the described experimental conditions, relaxes airway vascular smooth muscle but not bronchial smooth muscle. These results are consistent with previous suggestions that inhaled furosemide increases blood flow to airway tissues (Gilbert IA, Lenner KA, Nelson JA, Wolin AD, and Fouke JM. J Appl Physiol 76: 409-415, 1994).

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Arteries / drug effects
  • Arteries / physiology*
  • Bronchi / blood supply
  • Bronchi / drug effects
  • Bronchi / physiology*
  • Female
  • Furosemide / pharmacology*
  • In Vitro Techniques
  • Isoproterenol / pharmacology
  • Male
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / physiology*
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology*
  • Swine


  • Furosemide
  • Isoproterenol