Posterodorsal Medial Amygdala Mediates Tail-Pinch Induced Food Intake in Female Rats

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Neurobiology of Eating

Background:

• Comfort eating during stress is a widespread behavior in humans and animals.
• The precise neural mechanisms driving stress-induced food intake remain largely unknown.
• The amygdala, particularly the posterodorsal medial amygdala (MePD), is implicated in emotional processing and appetite regulation.

Purpose of the Study:

• To investigate the role of the amygdala's corticotropin-releasing factor (CRF) system in mediating stress-induced food intake.
• To determine if lesions to the MePD affect stress-induced feeding behaviors.
• To examine the effects of direct CRF and CRF antagonist administration into the MePD on food intake.

Main Methods:

• Utilized neurotoxic lesions (ibotenic acid) to target the MePD in rats.
• Administered CRF and a CRF receptor antagonist (astressin) directly into the MePD via cannulae.
• Assessed food intake in response to a tail-pinch stressor before and after interventions.

Main Results:

• MePD lesions significantly reduced food intake induced by tail-pinch stress.
• Direct administration of CRF into the MePD dose-dependently increased food intake, exhibiting a bell-shaped dose-response curve.
• Administration of the CRF antagonist astressin into the MePD blocked stress-induced feeding.

Conclusions:

• The posterodorsal medial amygdala (MePD) is a critical neural substrate for stress-induced food intake.
• The amygdala's CRF system acts as a mediator for stress-related feeding behaviors, potentially underlying 'comfort eating'.