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Detection of G Protein-coupled Receptor Expression in Mouse Vagal Afferent Neurons using Multiplex In Situ Hybridization
Published on: September 20, 2021
Ghrelin and the vagus nerve
1Frontier Science Research Center, University of Miyazaki, Kiyotake, Miyazaki, Japan. dateyuka@med.miyazaki-u.ac.jp
Methods in Enzymology
|September 15, 2012
Summary
Ghrelin, a feeding hormone, signals the brain via the vagal afferent system, not directly crossing the blood-brain barrier. This pathway is crucial for regulating appetite and growth hormone secretion.
Area of Science:
- Neuroendocrinology
- Gastroenterology
- Hormone signaling
Background:
- Ghrelin, a gastrointestinal hormone, stimulates feeding and growth hormone (GH) secretion.
- Its direct action on brain neurons via the ghrelin receptor (GHS-R) is debated due to the blood-brain barrier.
- Gastrointestinal hormones increasingly signal the brain through the vagal afferent system.
Purpose of the Study:
- To investigate the primary pathway through which ghrelin signals the brain for feeding and GH secretion.
- To determine if the vagal afferent system mediates ghrelin's effects.
Main Methods:
- Examined ghrelin's effects on feeding and GH secretion in rats.
- Utilized vagotomy and capsaicin treatment to disrupt the vagal afferent system.
- Investigated the presence and transport of GHS-R in vagal afferent neurons.
- Measured the firing rate of vagal afferent fibers after ghrelin administration.
Main Results:
- Ghrelin's effects on feeding and GH secretion were abolished or reduced after vagotomy or capsaicin treatment.
- GHS-R was found in vagal afferent neurons and transported to their terminals.
- Ghrelin administration decreased the firing rate of vagal afferent fibers.
Conclusions:
- The vagal afferent system is the predominant pathway for ghrelin to transmit signals to the brain.
- Ghrelin influences feeding and GH secretion by acting on the vagal afferent system, not necessarily by crossing the blood-brain barrier directly.
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