Smokers Have Reduced Nitric Oxide Production by Conducting Airways but Normal Levels in the Alveoli

• Published in: Inhalation toxicology Vol. 19; no. 6-7; pp. 533 - 541
• Main Authors: Pietropaoli, Anthony P., Perillo, Irene B., Perkins, Peter T., Frasier, Lauren M., Speers, Donna M., Frampton, Mark W., Utell, Mark J., Hyde, Richard W.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.2007; Taylor & Francis
• Subjects: Adult; Bronchi - metabolism; Exhalation - physiology; Female; Forced Expiratory Flow Rates - physiology; Humans; Male; Middle Aged; Nitric Oxide - biosynthesis; Pulmonary Alveoli - metabolism; Smoking - metabolism; Total Lung Capacity - physiology
• ISSN: 0895-8378; 1091-7691
• DOI: 10.1080/08958370701260673

Air exhaled by cigarette smokers contains reduced amounts of nitric oxide (NO). Measurement of NO at different expiratory flow rates permits calculation of NO production by the conducting airways (VawNO) and alveolar concentration of NO (PALV). An independent measurement of diffusing capacity of the alveolar compartment (DLNO) multiplied by PALV allows calculation of NO production by the alveoli (VLNO). Twelve asymptomatic cigarette smokers and 22 age-matched nonsmokers had measurements of DLNO and expired NO at constant expiratory flow rates varying from 60 to 1500 ml/s. VawNO in smokers was only 22 ± 11 nl/min (mean ± standard deviation, SD) compared to 70 ± 37 nl/min in nonsmokers (p < .0001). In contrast, VLNO showed no significant difference (smokers: 203 ± 104 nl/min, nonsmokers: 209 ± 74 nl/min, p = .86). These data show that the diminished NO expired by smokers results from diminished NO production by the tissues of the conducting airways but normal values produced by the alveoli.