PRODUCTION AND ABSORPTION OF NITRIC-OXIDE GAS IN THE NOSE

Some nitric oxide gas (NO) produced in the sinuses and nasal cavity is absorbed before leaving the nose. To measure production and absorptio n, we introduced NO at different concentrations into one nostril while sampling the NO leaving the opposite nostril with the soft palate clo sed. The quantity of NO gas produced in six normal subjects (amount le aving plus the amount absorbed) averaged 352 nl/min and was the same a t gas flows ranging from 8 to 347 ml/min and at 10 l/min. An absorptio n coefficient A was calculated by dividing the amount of NO absorbed b y the concentration leaving the nose. A ranged from 17 ml/min at a nas al gas flow of 8 ml/min to an A of 24 ml/min at a nasal gas flow of 34 7 ml/min. The calculated rates of production and absorption did not ch ange when gas flow rate was increased, suggesting diffusion equilibriu m. The amount of uptake of NO in the nasal mucosa can be explained by its solubility coupled with tissue and blood reactivity.