Exercise enhances learning and memory: the role of endogenous cannabinoid system.

BACKGROUND:

Endogenous cannabinoid system (ECS) is involved in regulating cognitive function, including learning and memory. It may be also involved in the enhancement of learning and memory after exercise.

METHODS:

In this study, a treadmill exercise training model of mice was established. After 4 weeks’ moderate treadmill exercise in C57BL/6J and CB1R specific knockout mice, Morris water maze was used to evaluate the spatial learning and memory ability of mice in each group. The expression of BDNF and CB1R in hippocampus was detected by Western blot. Dendritic spine density of pyramidal cells in the hippocampal CA1 region were analyzed by quantitative Golgi staining.

RESULTS:

Our results showed that AM281 injection and CB1R knockout of glutamatergic neurons eliminated the effect of exercise on learning and memory, and affected the increase of BDNF in hippocampus after exercise; CB1R-specific knockout mice on GABA neurons and glial cells did not affect the enhancement effect of learning and memory by exercise; In addition, the results of Golgi staining showed that exercise increased dendritic spine density in hippocampal neurons, but dendritic spine density did not change significantly in CB1R- specific knockout on glutamatergic neurons mice after exercise.

CONCLUSIONS:

From the above results, we infer that the ECS on glutamatergic neurons is involved in the enhancement of learning and memory by exercise, and BDNF plays an important mediating role during this process.