Experimental induction of chronic bronchitis in dogs: effects on airway obstruction and responsiveness

Chronic bronchitis was induced in 6 mongrel dogs by chronic exposure to SO2 gas; the degree of chronic airway obstruction and the effects on airway responsiveness to inhaled histamine, carbachol, and prostaglandin F2 alpha were examined. Five dogs developed chronic airway obstruction, as indicated by an increase in pulmonary resistance, and clinical mucous hypersecretion. In addition, in each of the animals in which chronic airway obstruction developed there was a decrease in the airway responsiveness to inhaled mediators. Those findings demonstrate that induction of chronic bronchitis in dogs results in hyporesponsiveness to inhaled mediators, a finding distinctly different from that reported in human subjects with naturally occurring disease.