Effects of damage of the l‐XII nerve that innervates tongue retractive muscles in rats

Abstract

The aim of this study was to examine whether sectioning of the lateral branches of the hypoglossal nerves (l-XII) in young male rats affects regulation of body weight, food intake and water intake in their period of growth by using a linear fixed effects model or not. Three groups of the rats were prepared according to treatments applied at about 4 weeks after birth to the l-XII innervating the hyoglossus, styloglossus and inferior longitudinal muscles: bilaterally sectioned (n = 9), unilaterally sectioned (n = 3) and sham-operated (n = 6) groups. Changes in body weight, food intake and water intake of the rats in the three groups were measured for 32 days before and after the treatments. To test the abilities of eating and drinking, the amounts of food and water intake were also measured for 1 and 2 min, respectively, after 20 h food and water deprivation at the final stage of the experiment. The major findings obtained were that (i) bilateral sectioning of the l-XII in the young rats significantly reduced body weight and the amount of water, not food, intake consumed and (ii) the bilateral sectioning affected the ability of eating and bilateral and unilateral sectioning affected that of drinking. The results suggest that bilateral sectioning of the lateral branches of XII nerve in young male rats affects regulation of body weight and water intake in their period of growth.