FLOW AND pH CHANGE OF SUBMAXILLARY SALIVA ASSOCIATED WITH VARIATIONS IN ACID-BASE EQUILIBRIUM

Abstract

Overventilation in dogs receiving a continuous injn. of pilocarpine produced an increase in the pH of both blood and saliva. These changes were attrib-uted primarily to decreased CO2 tensions. The change in salivary pH was smaller than the pH change in the arterial blood due apparently to the decrease in content of base resulting from. a slower rate of secretion. Adm. of low O2 in a mixture containing CO2 approximating the tension of this gas in the arterial blood produced a greater decrease of pH in saliva than in arterial blood. Disturbances of the cellular metabolism induced by the impairment of oxidations contributed to this decrease in salivary pH. Since the increased salivary flow accompanied the decreased salivary pH but preceded the blood pH decrease, the increased secretion was attributed to the increased intra-cellular acidity. Administering air containing more than 8% CO2 produced initially a greater pH decrease in blood than saliva followed by an increase and a further increase occurred on returning the animal to room air. With lower % of CO2 only increases in salivary pH were produced. Large injns. of lactic acid produced parallel decreases in both blood and saliva but the change in saliva was less. Small or slow injns. might produce an increase in salivary pH. NaHC03 injns. usually produced an increase in saliva pH which was much less than the pH increase in the blood. Sometimes the pH of saliva showed an initial decrease. NH4CI injns. produced much greater decreases in saliva pH than in blood. Saliva flow changes were related to variations of intracellular acidity rather than to the reaction of either blood or saliva. A probable mechanism for the enhancement of flow by an increase in intraglandular acidity is suggested.