Reflection of Salt Concentrations of Blood Upon Those of Saliva

It is not yet fully clarified how the blood salt concentration can reflect upon the salivary concentration.BEER and WILSON1) reported that the salt cencentration in saliva increased after intravenous injections of CaCl2 and Na2CO3.NISHIKAWA2) verified experimentally with dog's submaxillary gland that salivary-Na and Cl concentrations may vary according to changes in blood salt concentrations.On the other hand, DENTON3) verified that the salivary Na+/K+ ratio falls about 90 minutes after intravenous infusion of aldosterone into sodiumdepleted adrenal insufficient sheep.He further confirmed3) with Na depleted sheep that the secretion of aldosterone increased and that the salivary Na+/K+ ratio fell, while it rose after a certain delay period, when a hypertonic NaCl solution was injected into the systemic blood.He suggested that the infused Na did not act directly on the salivary gland, but indirectly through changing the secretion of aldosterone.From these results, he used Na+/K+ ratio in parotid saliva of sheep as a criterion of the secretion of aldosterone from the adrenal gland3).From the theoretical point of view, however, it seems reasonable to presume that the change in salt concentration in serum can directly influence upon that in saliva, since the salt in saliva mostly originates from that in tissue fluid and consequently from serum salt.Thus, many problems remain to be settled concerning the mechanism of reflection of blood salt concentration upon saliva.The aim of the present study is to clarify this mechanism by perfusing the salivary gland with blood of various salt concentrations.The experiments were divided into two series.The first series of experiments were performed to study the effects of varying blood osmotic pressures upon the salivary composition, while the second series were to investigate the effects of mineral corticoid upon salivary salt composition.