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

TL;DR

This study shows how binge eating and obesity differently affect the brain's endocannabinoid system in rats, with distinct patterns in reward-related brain regions.

Contribution

The study reveals distinct endocannabinoid system dysregulation patterns in binge eating versus obesity in rats, with region-specific and diet-type-dependent effects.

Findings

ECS expression varied across brain regions depending on palatable food access patterns.

ECS dysregulation was influenced by the type and quantity of food consumed.

The RMTg showed unique co-regulation patterns linked to eating behaviors.

Abstract

Binge eating disorder (BED) is characterized by the rapid overconsumption of palatable food in a short amount of time, often leading to obesity. The endocannabinoid system (ECS), a system involved in palatable food intake, is highly expressed in reward-related brain regions and is involved in both obesity and BED. This study investigated differences in ECS expression between these conditions using male Wistar rats exposed to specific regimen over six weeks: a non-access group (NA) with a standard diet, a continuous access group (CA) with free-choice high-fat high-sugar (fcHFHS) diet modeling obesity, and an intermittent access group (IA) with intermittent fcHFHS access modeling BED. Food intake was measured, and brain tissues from the nucleus accumbens (NAc), dorsal striatum (DS), ventral tegmental area (VTA), and rostromedial tegmental nucleus (RMTg) were analyzed for ECS expression using qPCR and mass spectrometry. We identified differential ECS expression across palatable food access groups, with variations depending on the brain region (striatal or mesencephalic). Correlation analyses revealed ECS dysregulations dependent on the type (fat or sucrose) and quantity of palatable food consumed. Comparative network analysis revealed co-regulation patterns of ECS-related genes with specific signatures associated with each eating pattern, highlighting RMTg as a key region for future research in eating behavior.

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