Effect of environmental lighting on aggressive and anxious behavior in male mine

To study the influence of the different conditions of environmental lightning on aggressive behavior and open field activity, male mice where kept under different conditions of environmental lighting, i.e., A) 12-hour each light and dark (LD), B) continuons light (LL) and C) continuous dark (DD) for 27 days. Although no significant differences were observed among three groups, LL and DD conditions tended to show the inhibitory effect on aggression. In the open field test, the Crossing, the time and the path significantly increased with the length of lighting period, but the rearing and defecation were not affected. The amounts of monoamines and their metabolites in the cerebellum, cerebrum and brainstem were hardly affected by lighting conditions. Taken together, DD condition was most preferable for mice to keep cal m rather LL condition.