Effects of perivagal administration of capsaicin on food intake in animals after noxious gastric surgery

Previous studies have shown that the perivagal administration of capsaicin induces greater food intake vs. controls at 24 h after the surgery but a similar intake to that of controls at 48 h. The present study aimed to determine whether the nutritive effect observed after perivagal capsaicin administration is due to the interruption of noxious vagal fibers in rats. For this purpose, postsurgical food intake was analyzed in control and capsaicin-treated animals with (Experiment 2) and without (Experiment 1) noxious lesions in the gastric wall. The results of both experiments showed that the food intake of capsaicin-treated animals was greater vs. control animals at 24 h but not at 48 h after the surgery (p<0.025), as previously demonstrated. However, the food intake of the capsaicin-treated lesion animals in Experiment 2, although still greater than that of the control group, was significantly less than the intake of the capsaicin-treated animals in Experiment 1 (p<0.01). Therefore, it appears unlikely that the demonstrated effect is produced by lesion to noxious vagal fibers destroyed by the capsaicin. On the contrary, it is more likely that the vagal afferent pathways are those related to short-term nutrition.