Sequential appetite suppression by oral and visceral feedback to the brainstem

Area of Science:

• Neuroscience
• Gastroenterology
• Behavioral Science

Background:

• Meal termination relies on neural circuits in the caudal brainstem.
• The caudal nucleus of the solitary tract (cNTS) integrates meal-related sensory signals.
• Understanding cNTS processing of ingestive feedback during feeding is crucial.

Purpose of the Study:

• Investigate how prolactin-releasing hormone (PRLH) and GCG neurons in the cNTS are regulated during ingestion.
• Elucidate the distinct roles of these neuronal populations in controlling feeding behavior.
• Determine the mechanisms by which sensory feedback influences feeding dynamics.

Main Methods:

• Recording neuronal activity (PRLH and GCG neurons) during nutrient infusion and oral consumption.
• Utilizing optogenetics to manipulate neuronal activity.
• Analyzing feeding behavior on short and long timescales.

Main Results:

• PRLH neurons exhibit phasic activity linked to orosensory cues during oral intake, controlling feeding burst duration.
• GCG neurons are activated by gut distension, tracking food amount and promoting longer-lasting satiety.
• Distinct cNTS circuits differentially process oral and visceral feedback.

Conclusions:

• Sequential orosensory and gut feedback engage separate cNTS circuits.
• These circuits control feeding behavior on distinct short (seconds) and long (minutes) timescales.
• This reveals a neural basis for dynamic regulation of meal duration and satiety.