The main purpose of this study was to investigate the effects of treadmill exercise and bright light exposure on serotonin expression in rat brain. Male Sprague-Dawley (SD) rats were randomly assigned into four groups (n=9 in each group), specifically, control group (CG), exercise group (EG), light group (LG), and exercise+light group (ELG). Rats in EG were subjected to treadmill exercise (5 days/week, 30 min/day), LG rats exposed (5 days/week, 30 min/day, 10,000 Lux), ELG rats subjected to treadmill exercise in combination with exposure, and CG rats remained sedentary over a four-week period. We observed a significant increase in serotonin expression in the raphe obscurus nucleu and the midbrain of rats in EG, LG, and ELG, compared to CG. Interestingly, serotonin expression was significantly increased in ELG, compared to EG and LG in the raphe obscurus nucleu via immunohistochemistry. In the western blot, it showed a increased pattern in ELG, compared to EG and LG. The overall results showed that treadmill exercise and/or bright light had positive effects on serotonin expression in the brain. Therefore, we suggest that moderate exercise or exposure to bright light during a growth child may be beneficial in brain action.
It has been reported that continuous exercise and bright light exposure improved resistance to stress and reduced depression and anxiety, which were attributed to enhancing neurotransmitter GABA exocytosis and stimulating neurogenesis. In this study, the effects of treadmill exercise and bright light exposure on the expression of GABAAreceptor activity, calcineurin and calcineurin calcium signaling pathway-depended NFATc4, neurogenesis-related protein Cdk5 and specific regulator factor of Cdk in neurogenesis p35 in the hippocampus of rats were investigated by western blot assay. The expression of GABAAreceptor, Cdk5 and p35 significantly increased in the exercise+light group compared to the control group and the light group. The expression of KCC2 and NFATc4 significantly increased in the exercise+light group compared to all the other groups. And the expression of calcineurin significantly increased in the exercise+light group compared to the control group. The overall results showed that exercise and bright light stimulated neurogenesis of the hippocampus in rats and had positive effects on improving the brain neuronal function.
