Immediate anaphylactic bronchoconstriction induces airway hyperreactivity in anaesthetized guinea‐pigs

Open Access
Publisher Website
Google Scholar
Abstract
1 The possible acute occurrence of airway hyperreactivity after immediate-type bronchial anaphylaxis has been investigated in anaesthetized guinea-pigs actively sensitized to ovalbumin (OA). 2 Aerosol challenge (OA 10 mg ml−1, 5s) provoked immediate bronchoconstriction which was substantially, although incompletely, reversed by isoprenaline (Iso) infusion (1 μg kg−1 min−1) for 10 min). 3 Bronchoconstrictor responses to 5-hydroxytryptamine (5-HT) were enhanced in challenged animals when compared to those in non-challenged animals that had also received Iso. This was seen as a leftward shift in the location of the dose-response curve for the bronchoconstrictor effect of 5-HT (dose-ratio 2.45, 95% confidence limits 1.77–3.38; P < 0.01). This phenomenon was associated with pulmonary infiltration of polymorphonuclear leukocytes, which was not modified by Iso treatment. 4 Iso infusion alone caused a slight enhancement of airway reactivity seen as a small leftward shift of the dose-response curve for the bronchoconstrictor effect of 5-HT (dose-ratio 1.51, 95% confidence limits 1.07–2.13; P < 0.05). 5 These results support a causal relationship between acute pulmonary inflammation and airway hyperreactivity in an animal model of human allergic asthma.