FURTHER STUDIES ON THE COMPOSITION OF SALIVA IN DIFFERENT PHASES OF THE SECRETION

Abstract

It had previously been shown that the composition of saliva from a dog with a permanent parotid fistula changes in different phases of the secretory period, the 3 phases then recognized being: (1) the 1st min. while the dog was being stimulated by food, etc.; (2) 1st min. of after-flow; (3) succeeding period of after-flow. For the present study, a 4-phase experiment was devised, phase 1 being separated into 2 30-sec. periods, phases 1A and 1B. Experiments were performed on 5 dogs with permanent salivary fistulae. Two dogs had each a single parotid fistula; 1 had a single submaxillary fistula and 1 parotid fistula; and 1 had 2 parotid fistulae. The saliva was collected according to the Pavlov method. The 4-phase type of experiment showed that the salivary secretion of the parotid and mixed glands is qualitatively and quantitatively different in the various periods. The Cl concentration in saliva from the parotid and mixed glands diminishes steadily from phase 1A to phase 3. The concentration of Cl has no relation to the amt. of organic matter secreted. In pilocarpine saliva, notwithstanding the increased secretion, there is invariably a fall in the organic and inorganic moieties, which cannot be attributed to exhaustion of the available supply. Therefore, the secretion of salts in the saliva under the influence of pilocarpine is not dependent only on the rate of secretion. Atropine injected in progressively greater amts. diminishes the total output of fluid parts and of ash in all 3 phases of salivary secretion. In the 3rd phase, however, it increased the total output of organic substances (diminished during the 1st and 2nd phase), when the dose of atropine injected did not exceed 2 mgm.