Increased short-term food intake after external lateral parabrachial subnucleus lesions in rats

The vagus nerve and several brainstem nuclei to which it projects have been closely associated with food intake. The aim of this study was to determine the degree to which the same or different information on food intake is processed by this nerve and by one of these nuclei, the external lateral parabrachial subnucleus (LPbNe). For this purpose, we analyzed the solid and liquid food intake of Wistar rats subjected to vagal deafferentation with capsaicin or lesions of the LPbNe. Vagotomized animals consumed significantly larger amounts of solid food during the first 24 h post-surgery but not at 48, 72, or 96 h. Animals with LPbNe lesions also consumed larger amounts of liquid and solid foods but only during periods of 60 min on day 5 and 90 min on day 6 post-surgery, respectively. According to these findings, both the vagus nerve and the LPbNe appear to be involved in short-term regulation of food intake, although they participate over different time scales. These data are discussed in terms of the potential importance of the vagal-parabrachial axis in the rapid processing of nutritional information from the upper gastrointestinal tract.