Journal of Applied Physiology, Vol 50, Issue 4 761-765, Copyright © 1981 by American Physiological Society
Basenji-Greyhound dog model of asthma: influence of atropine on antigen-induced bronchoconstriction
C. A. Hirshman and H. Downes
To test the relative importance of cholinergic effects on the
Basenji-Greyhound (BG) model of asthma, we administered Ascaris antigen to
Ascaris-sensitive BG dogs without other treatment, and following
intravenous atropine. Pulmonary resistance (RL) increased from 1.4 +/- 0.43
cmH2O . l-1 . s (mean + SE) to 26.0 +/- 5.21 after Ascaris antigen exposure
in seven untreated dogs. In the same dogs pretreated with 0.2 mg/kg
atropine, RL increased from 1.5 +/- 0.31 to 18 +/- 5.00. Atropine 0.4 and
1.0 mg/kg did not result in increased protection. Although 0.2 mg/kg
atropine markedly inhibited the airway responses to both inhaled citric
acid and methacholine, it only slightly prevented antigen-induced airway
constriction. We conclude that in BG dogs, cholinergic pathways elicit
bronchomotor responses to irritants but that the major component of
antigen-induced bronchoconstriction is not cholinergically mediated.
