Effect of ammonia on nasal resistance in atopic and nonatopic subjects

Nasal airway resistance (NAR) was assessed from the slope of pressure-glow curves obtained during normal nasal breathing. Volunteers were classified as atopic or nonatopic according to strict critera. 100 ppm NH3 was introduced into each nostril for periods ranging from 5 to 30 seconds with frequent NAR monitoring. A progressive increase in NAR responses was obtained with incremental NH3 exposure, but no significant difference was noted between the mean response of atopic and nonatopic subjects. Control exposures to compressed air under the same pressure generally produced only a small change in NAR, while aerosolized buffered saline increased NAR more than compressed air. The nasal response to NH3 was effectively inhibited by intranasal atropine administration but not by chlorpheniramine. The nasal response to NH3 was effectively inhibited by intranasal atropine administration but not by chlorpheniramine. The described procedure provides a safe and simple method for studying semiquantitatively the short-term effects of inhaled irritants on the nose.