Lingual Taste Nerve Transection Alters Food Selection, Relative Macronutrient Intake, and Meal Patterns in Rats...

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Physiology

Background:

• Ingestive behavior is regulated by complex sensory inputs, including gustatory signals from taste nerves.
• Lingual taste nerves, innervating a majority of taste buds, play an underappreciated role in controlling food selection and intake.

Purpose of the Study:

• To investigate the role of lingual taste nerves in regulating food selection, macronutrient intake, and meal patterns.
• To compare the effects of chorda tympani and glossopharyngeal nerve transection (2NX) versus sham surgery (SHAM) on ingestive behavior in rats.

Main Methods:

• Utilized a custom five-item Food Choice Monitor to assess behavioral responses to chow and a cafeteria diet (CAF).
• Compared postsurgical intake, meal patterns, and eating rates between male rats undergoing SHAM or 2NX surgery.
• Histological verification confirmed nerve transection in 2NX rats.

Main Results:

• 2NX rats consumed significantly more high-fat CAF foods, leading to increased fat and reduced carbohydrate intake compared to SHAM rats.
• 2NX rats exhibited altered meal patterns, eating fewer, larger meals daily for both chow and CAF.
• Eating rates suggested reduced motivation for chow but not CAF in 2NX rats, despite similar overall energy intake and weight gain.

Conclusions:

• Lingual taste nerve information is critical for nuanced food selection and macronutrient regulation.
• Taste pathways influence meal termination and eating patterns, but not long-term energy homeostasis.
• The study highlights the specific roles of taste in diet selection beyond simple energy balance.