IBRO neuroscience reportsJun 24, 2022

The debated role of the vagus nerve in how ghrelin affects the body and brain

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 6, 2026

Abstract

Studies in rats provide the most consistent evidence that the vagus nerve mediates some actions of ghrelin on the digestive and cardiovascular systems.

Ghrelin is a hormone from the stomach that influences various bodily functions through its receptor.
The vagus nerve may play a role in transmitting signals related to ghrelin's effects.
Anatomical studies have identified the presence of ghrelin receptors in vagal neurons.
Research in rats supports the idea that the vagus nerve is involved in ghrelin's influence on digestion and heart function.
Contradictory findings in mice suggest that the vagus nerve's role in ghrelin action is not fully understood.
Insufficient studies in humans prevent definitive conclusions about the vagus nerve's involvement in ghrelin's effects.

Simplified

Ghrelin is a stomach-derived peptide hormone that acts via the growth hormone secretagogue receptor (GHSR) and displays a plethora of neuroendocrine, metabolic, autonomic and behavioral actions. It has been proposed that some actions of ghrelin are exerted via the vagus nerve, which provides a bidirectional communication between the central nervous system and peripheral systems. The vagus nerve comprises sensory fibers, which originate from neurons of the nodose and jugular ganglia, and motor fibers, which originate from neurons of the medulla. Many anatomical studies have mapped GHSR expression in vagal sensory or motor neurons. Also, numerous functional studies investigated the role of the vagus nerve mediating specific actions of ghrelin. Here, we critically review the topic and discuss the available evidence supporting, or not, a role for the vagus nerve mediating some specific actions of ghrelin. We conclude that studies using rats have provided the most congruent evidence indicating that the vagus nerve mediates some actions of ghrelin on the digestive and cardiovascular systems, whereas studies in mice resulted in conflicting observations. Even considering exclusively studies performed in rats, the putative role of the vagus nerve in mediating the orexigenic and growth hormone (GH) secretagogue properties of ghrelin remains debated. In humans, studies are still insufficient to draw definitive conclusions regarding the role of the vagus nerve mediating most of the actions of ghrelin. Thus, the extent to which the vagus nerve mediates ghrelin actions, particularly in humans, is still uncertain and likely one of the most intriguing unsolved aspects of the field.

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The debated role of the vagus nerve in how ghrelin affects the body and brain

Abstract

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