Inhaled mannitol shifts exhaled nitric oxide in opposite directions in asthmatics and healthy subjects

Respir Physiol. 2001 Jan;124(2):141-50. doi: 10.1016/s0034-5687(00)00195-x.

Abstract

We investigated if healthy subjects could release NO upon hyperosmolar challenge as a defence mechanism, and whether asthmatics with atopy showed an altered response. A plot of NO output versus flow rate was used to calculate the alveolar level and the NO-flux from the airways. The asthmatics had a higher NO output and this was due to an increased NO-flux from the airways, 86+/-30 nl min(-1) compared with control 21+/-2 nl min(-1) (P<0.05). The alveolar NO levels showed no difference. In response to a dry powder of mannitol the exhaled NO concentration decreased in asthmatics by 37+/-7%, but increased in the control by 9+/-4% (P<0.001). The FEV(1.0) decreased 13+/-2% and airway conductance 42+/-7% in asthmatics and in the controls 2+/-1% and 0+/-7%, respectively (P<0.001). We conclude that asthmatics have an altered response to mannitol challenge in regards to exhaled NO. This may result from down regulation of constitutive NO production as a result of high levels of NO flux from the airways.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Administration, Inhalation
  • Adult
  • Asthma / physiopathology*
  • Female
  • Forced Expiratory Volume / drug effects
  • Humans
  • Male
  • Mannitol / administration & dosage
  • Mannitol / pharmacology*
  • Methacholine Chloride / pharmacology
  • Nitric Oxide / metabolism*
  • Osmolar Concentration
  • Pulmonary Alveoli / drug effects*
  • Pulmonary Alveoli / metabolism
  • Respiratory Function Tests

Substances

  • Methacholine Chloride
  • Nitric Oxide
  • Mannitol