Is airways hyperreactivity selective or non-selective?

Airways hyperresponsiveness has often been termed "nonspecific" on account of close correlations between responses to histamine and methacholine. This relationship, however, does not apply to stimuli, such as exercise, hyperventilation, sulphur dioxide, and distilled water. We have shown that allergen causes a greater and more prolonged increase in responses to bradykinin than to methacholine adding support to the notion that airways hyperresponsiveness is a selective pathophysiologic abnormality.