Immediate anaphylactic bronchoconstriction induces airway hyperreactivity in anaesthetized guinea-pigs.
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, 5 s) provoked immediate bronchoconstriction which was substantially, although incompletely, reversed by isoprenaline (Iso) infusion (1 microgram 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 less than 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 less than 0.05). 5. These results support a causal relationship between acute pulmonary inflammation and airway hyperreactivity in an animal model of human allergic asthma.
Daffonchio
L
L
Department of Pharmacology, Wellcome Research Laboratories, Beckenham, Kent.
Payne
A N
AN
Lees
I W
IW
Whittle
B J
BJ
D000403:Airway Resistance / Q000187:drug effects; D000707:Anaphylaxis / Q000503:physiopathology*; D000818:Animals; D001980:Bronchi / Q000503:physiopathology; D006168:Guinea Pigs; D007545:Isoproterenol / Q000494:pharmacology; D008168:Lung / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000473:pathology; D010047:Ovalbumin / Q000276:immunology; D012130:Respiratory Hypersensitivity / Q000473:pathology / Q000503:physiopathology*; D012701:Serotonin / Q000494:pharmacology
D012701:Serotonin; D010047:Ovalbumin; D007545:Isoproterenol