Journal of Applied Physiology, Vol 38, Issue 1 96-100, Copyright © 1975 by American Physiological Society
Mechanical properties of the lungs and experimental asthma in conscious allergic dogs
D. Dain and W. M. Gold
Three allergic dogs were trained to swallow an esophageal balloon, breathe
through a tracheostomy tube, and stand quietly in a wooden stall. The
mechanical properties of their lungs were measured reproducibly over many
months. Average values were: pulmonary resistance 1.33 cmH2O/l per s,
static lung compliance 104 ml/cmH2O, and functional residual capacity 982
ml. In two dogs inhalation of histamine aerosol caused a 374% increase in
resistance; inhalation of Ascaris suum aerosol caused a 307% increase in
resistance. The increased resistance was associated with mild-to-moderate
respiratory distress and slightly increased functional residual capacity.
Aerosols of isoproterenol or atropine sulfate inhibited the increased
resistance. We conclude that the conscious allergic dog is a suitable
subject for the long-term study of asthma. Our present results are
consistent with our earlier findings in anesthetized dogs, that a vagal
reflex is involved in acute bronchomotor responses to inhalation of
histamine as well as specific antigen.
