Role of Thalamic Gustatory Nucleus in Diet Selection by Normal and Parathyroidectomized Rats. ∗

Abstract

Summary

Young male Sherman rats were allowed to select individual components of their diet from 9 sources. After the selection of dietary items became relatively stable, a group of the animals was parathyroidectomized to intensify their need for one dietary component, calcium, while the rest of the animals served as unoperated controls. The role of thalamic gustatory neurons in mediating the response to dietary needs was then determined by destroying the thalamic gustatory nucleus in a certain number of the Ptx and the unoperated animals. Thalamie lesions which spared the gustatory neurons were also made to provide for adequate controls. If the thalamic lesions destroyed gustatory neurons in Ptx rats, the animals significantly reduced calcium intake. This reduction was sufficiently large to cause tetany and death in some of the animals. Changes in the consumption of sodium dibasic phosphate, sodium chloride, and distilled water also occurred. Destruction of the thalamic gustatory nucleus in previously normal rats did not diminish calcium intake significantly but the consumption of this item as well as other components of the diet became highly variable. These findings indicate that the gustatory system usually exerts a profound influence on the selection of diet not only under special circumstances but also in normal rats.