Peroxidase Antimicrobial System of Human Saliva: Hypothiocyanite Levels in Resting and Stimulated Saliva

The antimicrobial oxidizing agent hypothiocyanite ion (OSCN-) was measured in resting (drooling) and stimulated (expectorated) whole saliva. Stimulation of the saliva flow rate resulted in a rapid decrease in OSCN- concentration, whereas the thiocyanate ion (SCN-) concentration and peroxidase activity were increased. The decrease in OSCN- levels was greater than could be accounted for by dilution of the whole saliva volume. Assuming that the antimicrobial activity of the salivary peroxidase system is proportional to OSCN- concentration, this system may be more effective in resting saliva than in stimulated saliva.