Effect of physical training and palatable diet consumption on the expression of endocannabinoid system components in...

The endocannabinoid system (ECS) plays a pivotal role in regulating energy balance. While ECS activation stimulates appetite and increases preference for palatable food, it also enhances energy expenditure by motivating physical activity. This study investigated the impact of two key energy balance modulators - consumption of a palatable diet and the practice of aerobic physical activity - on the expression of CB1 receptor and NAPE-PLD enzyme in the rat brain.

Male Wistar rats, weaned at 3 weeks, were divided into 4 groups: standard-diet untrained, standard-diet trained, palatable-diet untrained, and palatable-diet trained. Trained groups underwent treadmill exercise while the palatable diet groups were fed accordingly. After 8 weeks, rats were euthanized for blood and brain collection. Western blotting assessed CB1 and NAPE-PLD proteins expression in the frontal cortex, hypothalamus, and preoptic area. Physical performance, body weight, adiposity index, and plasma levels of leptin, insulin, and glucose were measured.

Aerobic training enhanced physical performance, while a palatable diet increased the adiposity index and plasma leptin levels. In the hypothalamus, both interventions reduced CB1 and NAPE-PLD proteins, while increasing them in the frontal cortex. Physical training and the palatable diet decreased NAPE-PLD in the preoptic area.

These findings indicate that exposure to a palatable diet and aerobic training during early life exerts distinct effects on ECS signaling within the central nervous system. This study provides novel evidence that dietary and physical activity patterns can differentially shape brain ECS components, offering insights into their potential roles in energy homeostasis and obesity development.