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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.