Behavioral effects of aluminum in mice: Influence of restraint stress

The influence of restraint stress on potential aluminum (Al)-induced behavi oral changes was assessed in CD-1 mice. Three groups of adult mice were giv en 0, 300 and 600 mg Al/kg body weight per day in drinking water for 2 week s. One-half of the animals in each group were concurrently subjected to res traint stress during 1 h per day throughout the study. After cessation of t reatment, open-field activity, active avoidance learning, and motor resista nce and coordination of the animals were evaluated. At the end of the behav ioral testing period, mice were killed and Al concentrations were determine d in a number of tissues. There were no remarkable effects of Al, restraint stress or their combined administration on either open-field activity or o n the number of avoidances in an automatic reflex conditioner. However, a l ower motor resistance and coordination in a rotarod were observed following exposure to Al at 600 mg/kg/day, restraint alone or concurrent administrat ion of Al (300 and 600 mg/kg/day) plus restraint stress. The levels of Al i n whole brain and cerebellum were significantly enhanced in mice exposed to Al plus restraint. Although the present results scarcely show Al-induced n eurobehavioral effects, the influence of restraint stress on Al levels in w hole brain and cerebellum can be the basis for further studies on the poten tial role of this element in certain neurological disorders.