The effect of different types of stimulation upon the pH of human parotid secretion.

Abstract

The secretion was obtained by means of attaching suction discs over the mouth of Stenson''s duct. The pH detns. were made electrometrically with the Beckman glass electrode pH meter. Regardless of the nature of the agent used, pH parallelled secretory rate. The more rapidly flowing secretions were more alkaline, the slower rates were associated with a more acidic secretion. The degree of acidity or alkalinity remained relatively constant when the rate remained constant even though gustatory, olfactory, proprioceptive, or summated stimulation was used. By ac- tivating one gland more than the other and collecting the secretions simultaneously it was possible to obtain an alkaline secretion from the more active gland and an acidic secretion from the less active one. During periods of prolonged mental activity, fatigue, sleep, or any state in which the glandular activity is inhibited, the secretion is acidic. Inactivated secretions with a pH as low as 5.43 and activated secretions of a pH as high as 8.18 were obtained. The average pH of the normal inactivated secretions observed was 5.9.