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Updated: May 3, 2026

Murine Model of Allergen Induced Asthma
Published on: May 14, 2012
Differential effects of methacholine and antigen challenge on gas exchange in allergic subjects
Abstract:
In order to better characterize the differential effects of nonspecific and specific (antigen) bronchial challenge on gas exchange, seven ragweed-sensitive subjects with a history of asthma underwent progressive inhalation challenge with methacholine and ragweed extract on two different days. For comparable severity of bronchospasm (mean specific airway conductance 0.05 sec-1cm-1H2O for methacholine and 0.06 sec-1cm-1H2O for ragweed), there was a greater decrease in mean arterial oxygen saturation after ragweed (4.7%) than after methacholine challenge (2.7%) (p less than 0.05). While this was not accompanied by differences in static lung volumes, the density-dependent index decreased by 19% after ragweed (p less than 0.001) but remained unchanged after methacholine challenge. These results suggest that a greater involvement of peripheral airways in the bronchospastic response is, at least in part, responsible for the greater decrease in arterial oxygen saturation after ragweed challenge.
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