Sodium and Potassium as Constituents of Human Salivary Buffers

Abstract

In the series of samples obtained from 80 consecutive patients, the increases in the buffering power of stimulated saliva as contrasted to that of resting saliva ranged from 27% to 400%, with a mean of 150%. The magnitude of difference was, in general, related to the rate of flow. Whereas K is the predominant cation in the buffer systems of resting saliva, Na predominates in stimulated saliva. Of the anions contributing to the salivary buffers, phosphates and proteins decrease in concn. and bicarbonates increase in concn. when the salivary glands are activated by the masticatory process. In 22 of 25 cases studied, the total increase in Na and bicarbonate concn. of stimulated saliva was considerably greater than the total change in K, phosphate, and protein concn. The greater buffer power of stimulated saliva as contrasted with that of resting saliva in the same person is due to the increase in the quantity of Na and bicarbonate elaborated by the salivary glands in response to stimulation.