The Uptake of Sodium Ions by the Tongue

We have seen a wealth of data demonstrating that salt prefer­ ence thresholds decrease as salt deprivation continues. Careful studies indicate that these fluctuations cannot be accounted for in terms of changes in neural excitatory thresholds. It is reasonable to assume that something on or about the tongue may change with sodium deprivation. The problem approached in this study was the search for evidence of such a change.

The experimental hypothesis was, "that sodium ions actually penetrate the surface of the tongue according to the sodium depriva­ tion experienced by the animal."

This was basically a search for processes associated with changes in behavior. It was attempted to demonstrate concomitant changes in the drinking of solutions of sodium chloride with the same periods of sodium deprivation.

There was also an attempt to determine the effects of sodium deprivation on the level of serum sodium in rabbits. It is known that the sodium concentration in human serum does not change significantly during sodium deprivation (Walker, Boyd & Asimov, 1952). Everett (1944) discusses the mechanisms believed to be involved in resisting changes in serum sodium concentration. Large quantities of water are excreted while sodium is reabsorbed by the renal tubules. Desoxycorticosterone plays a role in this reabsorption. Mraz* found that the sodium concentration in the serum of rats does not change significantly during sodium deprivation.