Binge Eating and Obesity Differentially Alter the Mesolimbic Endocannabinoid System in Rats

Area of Science:

• Neuroscience
• Neurobiology of Eating Disorders
• Metabolic Research

Background:

• Binge eating disorder (BED) involves rapid overconsumption of palatable foods, often leading to obesity.
• The endocannabinoid system (ECS) plays a crucial role in regulating palatable food intake and is implicated in obesity and BED.
• Understanding ECS alterations in different feeding patterns is vital for developing targeted interventions.

Purpose of the Study:

• To investigate differential endocannabinoid system (ECS) expression in rat models of obesity and binge eating disorder (BED).
• To identify brain regions and ECS pathways associated with palatable food consumption patterns.
• To explore the relationship between ECS dysregulation and the type/quantity of palatable food intake.

Main Methods:

• Male Wistar rats were subjected to six-week regimens modeling non-access, continuous access (obesity model), and intermittent access (BED model) to high-fat, high-sugar diets.
• Food intake was quantified.
• ECS gene and protein expression in the nucleus accumbens (NAc), dorsal striatum (DS), ventral tegmental area (VTA), and rostromedial tegmental nucleus (RMTg) were analyzed using qPCR and mass spectrometry.

Main Results:

• Significant differences in ECS expression were observed across palatable food access groups and varied by brain region (striatal vs. mesencephalic).
• ECS dysregulations correlated with the type (fat/sucrose) and amount of palatable food consumed.
• Network analysis revealed distinct co-regulation patterns of ECS genes, with specific signatures for each eating pattern.

Conclusions:

• Palatable food access significantly alters endocannabinoid system (ECS) expression in a region-specific manner.
• The rostromedial tegmental nucleus (RMTg) emerges as a key brain region for understanding the neurobiology of binge eating disorder (BED) and related eating patterns.
• These findings provide insights into the neurobiological underpinnings of obesity and BED, highlighting the ECS as a potential therapeutic target.