Significantly Reduced Salivary Nitric Oxide Levels in Smokers

Background: NO is a free radical gas with manifold physiologic functions primarily as a biologic messenger. Recently we reported the presence of NO in freshly secreted human saliva. We report here a significant reduction of salivary NO production in current smokers compared to non-smokers.

Patients And Methods: Saliva was collected from smokers (27 donors) and non-smokers (21) after rinsing the mouth with an antiseptic. Freshly secreted saliva, about 200-300 microliters, was collected within the first 30-60 seconds after mouth rinsing. NO was assayed using the Griess reagent which measures its byproduct NO2. The values thus obtained were statistically analysed using the Wilcoxon test.

Results: Our studies indicate significantly decreased NO levels as measured by its product NO2 in freshly secreted saliva in smokers compared to non-smokers (p = 0.0042). The median NO2 level in smokers was 64.85 microM, in non-smokers 194.45 microM, respectively.

Conclusions: The role of salivary NO in normal physiology is as yet unknown, however, the finding of reduced salivary NO levels in smokers suggests a potential role in the pathogenesis of smoking related morbidity of the upper aerodigestive tracts.