# How NTS NPY neurons alter NTS circuitry to promote food intake

> **NIH DK R01** · WASHINGTON STATE UNIVERSITY · 2026 · $514,223

## Abstract

Obesity is a major health problem in the United States and a leading contributor to cardiovascular disease,
diabetes mellitus and stroke. One region essential for the control of meal size is the nucleus of the solitary
tract (NTS) in the brainstem. Vagal afferent fibers carrying different types of satiety information from the GI
terminate in the NTS, and NTS neurons process this information before relaying it on to other brain regions
to terminate a meal. Activation of NTS neurons therefore critically impacts meal length. However, NTS
neurons are extremely heterogeneous in their expression of peptides and receptors. Activation of most NTS
neuronal populations inhibits FI, including general activation of NTS neurons expressing catecholamines
(NTS-CA). However, recently a subpopulation of NTS-CA neurons that express NPY and project to the
arcuate nucleus were found to stimulate FI. Interestingly, intra NTS injections of NPY stimulates FI.
Furthermore, our preliminary data suggest that both NPY and NE inhibit vagal activation of NTS neurons
and that stimulating NTS NPY neurons inhibits neighboring NTS neurons. Taken together, these are
intriguing results, but there are critical gaps in our knowledge about how these neurons impact the
activity of other NTS neurons, how NTS NPY neurons are activated and if their function changes with
metabolic state. Our central hypothesis for this proposal is that NTS NPY neurons release NPY and NE
locally to inhibit anorexigenic NTS neurons and the level of release is determined by a balance of excitatory
vagal drive and GABA inhibition, which is impacted by fasting and diet. We will test this hypothesis
rigorously and comprehensively by pursuing the following specific aims: Aim 1. Determine the effects of
locally released NPY and NE on NTS neuronal function. Aim 2. Elucidate what determines the activity of
NTS NPY expressing neurons. Aim 3. Determine whether the activity of NTS NPY neurons and the effects
of NPY and NE are altered dur

## Key facts

- **NIH application ID:** 11286841
- **Project number:** 5R01DK138673-03
- **Recipient organization:** WASHINGTON STATE UNIVERSITY
- **Principal Investigator:** Suzanne M Appleyard
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** DK
- **Fiscal year:** 2026
- **Award amount:** $514,223
- **Award type:** 5
- **Project period:** 2024-04-01T00:00:00 → 2028-01-31T00:00:00

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11286841

## Citation

> US National Institutes of Health, RePORTER application 11286841, How NTS NPY neurons alter NTS circuitry to promote food intake (5R01DK138673-03). Retrieved via AI Analytics 2026-05-20 from https://api.ai-analytics.org/grant/nih/11286841. Licensed CC0.

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