bioRxiv : the preprint server for biologyJul 15, 2026

Separate processing of body signals in the brain's area that controls vomiting and blood pressure

GLP-1 Therapies Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jul 16, 2026

Abstract

Neurons expressing GFRAL are activated when mice consume food rich in fat, which is required for fat satiation.

Activation of GFRAL neurons occurs specifically in response to high-fat food consumption.
This activation is essential for the sensation of fullness from fat and does not rely on the hormone GDF15 or traditional gut-brain signaling.
Neurons expressing GIPR inhibit GFRAL neurons and are activated by sugar, allowing for macronutrient-specific responses.
CALCR neurons are involved in linking intestinal conditions to reduced feeding, while PRLHR neurons respond to alterations in blood volume and pressure.
Findings highlight the diverse roles of area postrema neurons in monitoring physiological signals beyond nausea.

Simplified

Nausea arises from activation of specialized neurons in the area postrema (AP) ^1-8 . The AP also mediates much of the satiety produced by GLP1R agonists ^9-12 , suggesting a broader role in non-aversive physiology, yet the functions of AP cell types are not well understood. Here, we have used optical recordings in behaving mice to systematically define the natural regulation of an array of AP neurons, including the cell types that are principal targets of widely-used weight loss drugs. We discover that neurons expressing GFRAL, the receptor for the sickness-related hormone GDF15, are unexpectedly activated when mice consume food rich in fat. This fat-specific GFRAL neuron activation is required for fat satiation but does not involve GDF15 or canonical gut-brain pathways. Instead, "anti-nausea" neurons expressing GIPR, which directly inhibit GFRAL neurons, are selectively activated by sugar, enabling macronutrient-specific gating of GFRAL responses. In addition, we show that CALCR neurons link intestinal hyperosmolality to the suppression of feeding, whereas PRLHR neurons respond to changes in blood volume and pressure. These findings reveal a broad role for AP cell types in sensing and responding to physiologic signals unrelated to nausea. They also reveal that GFRAL and GIPR neurons, which are key targets of the weight-loss drug tirzepatide, have a natural function in sensing ingestion of fat and sugar, respectively.