The nucleus of the solitary tract (NTS) is emerging as a major site of action for the appetite-suppressive effects of leading pharmacotherapies currently investigated to treat obesity. However, our understanding of how NTS neurons regulate appetite remains incomplete.
In this study, we used NTS nutrient sensing as an entry point to characterize stimulus-defined neuronal ensembles engaged by the NTS to produce physiological satiety.
We combined histological analysis, neuroanatomical assessment using inducible viral tracing tools, and functional tests to characterize hindbrain-forebrain circuits engaged by NTS leucine sensing to suppress hunger.
We found that NTS detection of leucine engages NTS prolactin-releasing peptide (PrRP) neurons to inhibit AgRP neurons via a population of leptin receptor-expressing neurons in the dorsomedial hypothalamus. This circuit is necessary for the anorectic response to NTS leucine, the appetite-suppressive effect of high-protein diets, and the long-term control of energy balance.
These results extend the integrative capability of AgRP neurons to include brainstem nutrient sensing inputs.