Abstract

In this two-part experiment, I examined nervous system correlates of feeding behavior in fifteen-day-old rat pups. In the first part of the experiment, rat pups were duodenally infused with either O.8M glucose or isotonic saline. These pups were allowed to feed, and their behavior was scored. The pups that received glucose infusions ate less and also stopped eating at a lower level of stomach fill than pups that received saline infusions. In the second part of the experiment, possible neural correlates to this behavior were studied using c-Fos immunocytochemistry. Again, pups received infusions, but they were not allowed to feed. The pups' brains were then analyzed in regions shown in previous studies to exhibit neural activity in response to feeding (the area postrema, AP , and the nucleus tractus solitarius, NTS). In the caudal and rostral regions of the NTS, the level of c-Fos expression was similar in the glucose-infused and saline- infused animals. However, in the region of the NTS at AP and in the AP itself, saline-infused and glucose-infused animals appeared to exhibit differences in c-Fos expression, but this difference did not reach statistical significance. These results suggest continued development of nervous system control mechanisms between weaning and adulthood.