Vagotomy attenuates suppression of sham feeding induced by intestinal nutrients.

The ability of intraintestinal nutrient infusions to suppress sham feeding was examined in intact rats and in rats with total subdiaphragmatic vagal transections. Vagotomy abolished the suppression of sham feeding by intraintestinal infusion of maltose or oleate. Suppression of sham feeding by intraintestinal L-phenylalanine was reduced but not abolished by vagotomy. The results of this examination indicate that the vagus nerve mediates suppression of the sham feeding by intraintestinal maltose and oleate but is only partially responsible for suppression of food intake produced by L-phenylalanine. Taken together with previously published data these results suggest that effects on feeding by specific nutrients may be mediated by anatomically distinct populations of visceral afferent neurons.