Satiation and re-intake after partial withdrawal of gastric food contents: A dissociation effect in external lateral parabrachial lesioned rats

• Gastrointestinal (GI)vagal signals are processed through the parabrachial complex.
• Satiation and meal re-intake were examined after partial stomach food removal.
• Lesions of the external lateral nucleus (LPBe) do not affect meal satiation.
• However, they impair food re-intake after partial gastric nutrient withdrawal.
• LPBe appears to be critical in nutritional processes requiring rapid GI food signals.

Sensory information from the gastrointestinal system can be transmitted to the brain through the vagus nerve, the intermediate-caudal region of the nucleus of the solitary tract (NST), and various subnuclei of the parabrachial complex, notably the external lateral subnucleus (LPBe). The objective of the present study was to examine the relevance of this subnucleus in satiation and food reintake after gastrointestinal food removal. LPBe-lesioned animals were subjected to a re-intake task following the partial withdrawal of gastric food contents shortly after satiation. Lesioned and control animals ingested a similar amount of the initial liquid meal. However, after withdrawal of one-third of the food consumed, LPBe-lesioned rats were not able to compensate for the deficit created, and their re-intake of food was significantly lower than the amount withdrawn after the satiating meal. In contrast, the food re-intake of control animals was similar to the amount withdrawn. Hence, the LPBe does not appear to be critical in the satiation process under the present experimental conditions. However, the LPBe may be part of a system that is essential in rapid visceral adjustments related to short-term food intake, as also shown in other gastrointestinal regulatory behaviors that require immediate processing of visceral sensory information.