# Functional role of Gastrin Releasing Peptide (GRP) and GRP expressing neurons in the gustatory cortex

> **NIH NIH R01** · STATE UNIVERSITY NEW YORK STONY BROOK · 2024 · $553,565

## Abstract

PROJECT SUMMARY
 It is well-established that neural activity in the rodent gustatory cortex (GC) encodes taste, taste-predictive
cues and taste-guided decisions. These neural signals play an important role in guiding behaviors related to
taste and consumption. Recent electrophysiological and imaging studies demonstrated that GC can also process
interoceptive information pertaining to the homeostatic control of feeding and drinking, with hunger/satiety and
thirst/quenching affecting neural activity on both the slow time scale of ongoing activity and the fast time scale
of taste- and cue-evoked activity. The GC circuits and neurochemicals involved in processing interoceptive
signals as well as their role in driving specific behavioral responses are not fully understood yet.
 We propose to address this gap by focusing on a neuropeptide, the gastrin-releasing peptide, (GRP), and a
GC population of neurons producing GRP. As GRP is a feeding-suppressing peptide, neurons expressing GRP
(GRP+) are ideal candidates to sense homeostatic states and mediate the effects of GC on consumption. Our
preliminary data show that GC GRP+ neurons project to the basolateral nucleus of the amygdala (BLA) – a
nucleus known for its role in mediating aversive and appetitive behaviors – corroborating the idea that this
population of cells may indeed control behavior and lead to meal termination.
 The experiments in this proposal we will test the overarching hypothesis that GC GRP+ neurons process
interoceptive homeostatic signals at both the slow and fast temporal scales of ongoing and taste/cue-
evoked activity, and are capable of inhibiting consumption. Anatomical and immunohistological methods,
in vitro patch clamp electrophysiology, 2-photon (2P) calcium imaging in behaving mice, and
optogenetic/pharmacological manipulations will be used to address the following specific aims: Aim #1 will rely
on anatomical methods, patch clamp and optogenetics to establish neurochemical identity, electrophysiological
properties, laminar distribution and connectivity of GC GRP+ neurons. The studies will test the hypothesis that
GC GRP+ neurons are excitatory neurons sending projections to BLA and that GRP released by these neurons
modulates the activity of BLA circuits. Aim #2 will use 2P calcium imaging to study the activity patterns of GRP+
and GRP- neurons in mice engaged in behavioral tasks probing taste and anticipatory-cues processing under
distinct homeostatic conditions. These experiments will test the hypothesis that activity of GC GRP+ neurons,
and specifically those projecting to BLA, integrate sensory signals related to nutrients (taste and cues) with
homeostatic signals related to meal termination. Finally, Aim #3 will rely on optogenetic activation at different
time scales to establish the behavioral contribution of GC GRP+ neurons and investigate the neurochemical
bases of this effect. The experiments will test the hypothesis that GC GRP+ neurons provide a meal terminatio...

## Key facts

- **NIH application ID:** 10863989
- **Project number:** 5R01DC020722-02
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** Alfredo Fontanini
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $553,565
- **Award type:** 5
- **Project period:** 2023-06-09 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10863989

## Citation

> US National Institutes of Health, RePORTER application 10863989, Functional role of Gastrin Releasing Peptide (GRP) and GRP expressing neurons in the gustatory cortex (5R01DC020722-02). Retrieved via AI Analytics 2026-05-29 from https://api.ai-analytics.org/grant/nih/10863989. Licensed CC0.

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