New method for evaluating bronchomotor and bronchosecretory activities: Effects of prostaglandins and antigen.

We devised a new method for measuring responses of canine airway musculature, bronchosecretion and bronchial vasculature simultaneously, in situ, and investigated the effects of prostaglandins F2alpha and E2 and antigen-antibody reaction by using this model. The right bronchial artery was perfused with blood at a constant flow under artificial respiration. Airway musculature response was measured as a change in ventilation overflow with a modification of the Konzett-Rössler method; the airway secretory activity was measured with our stopper method for secretion volume and with the glass plate method for viscosity. Close intraarterial injections of prostaglandin (PG) F2alpha, 0.01--10 microgram, into the right bronchial artery produced bronchomuscular and vascular constrictions, while those of PGE2, 0.01--3 microgram, produced dilatation in a dose dependent manner. A close intraarterial injection of 1 mg protein of ascaris suum antigen to dogs with positive skin reaction produced bronchoconstriction and vascular dilatation. Thirty min intraarterial infusions of PGF2alpha, 0.3--3 microgram/min, and ascaris antigen, 0.03--0.3 mg protein/min, resulted in a dose-dependent increase in the volume of airway secretions, while those of PGE2, 0.1--1.0 microgram/min, did not alter the secretory activity. These findings indicate that prostaglandin F2alpha in relatively high doses increases both bronchomotor tone and bronchosecretory activity, as does antigen-antibody reaction with ascaris antigen, and that the present method is useful for evaluating effect of drugs on the respiratory tract.