Cholinergic nasal hyperreactivity in atopic subjects.

Increased nasal secretions are a fundamental component of allergic rhinitis. In order to analyze various parameters of nasal secretions, a relatively nontraumatic method for collecting nasal secretions was required. A small, flexible rubber catheter connected to a vacuum and inserted 4 cm into the nose proved to be an efficient method for recovering secretions produced from a series of nasal washes. An average of 67% of the washings were recovered and analyzed for protein content. Topical methacholine (5 to 100 mg) stimulated a dose-related increase in the amount of protein secreted with atopic patients demonstrating significantly more responsiveness than nonatopic patients (29.9 times the prechallenge production of protein for atopic patients and 4.8 times for nonatopic patients). Pretreatment with atropine (10 micrograms) reduced the effects of methacholine in atopic subjects, indicating that the secretory activity was in response to muscarinic receptor stimulation. Therefore, in addition to the array of autonomic abnormalities already recognized in atopic patients, these subjects are also hyperresponsive to nasal cholinergic stimulation.