Accumulating evidence indicates that the endocannabinoid system plays an essential role in the development and maturation of the central nervous system. Studies also have demonstrated that neural systems that regulate behavioral responses can be influenced by exercise during development. Exercise and endogenous cannabinoid activity have independently been shown to regulate brain plasticity, hence demonstrating a promising field of the endocannabinoid–exercise interaction. In order to investigate whether physical exercise during development would promote changes the brain endocannabinoid system, we investigated the cannabinoid receptor type 1 (CB1) expression in the brain of rats trained during the adolescent period. The results showed that an aerobic exercise program performed during adolescence significantly reduced the CB1 receptor expression in the striatum and hippocampal formation. These findings suggest an important link between the endocannabinoid system and physical training in adolescence.
