マンガン,亜鉛および銅の長期間投与が加齢マウスの学習・記憶能に与える影響について

抄録

Trace elements such as manganese (Mn), zinc (Zn) and copper (Cu) are essential elements, but excess amounts of these elements are known to cause many neurodegenerative diseases including Alzheimer’s disease (AD) and Parkinson’s disease (PD). The risk of excessive intake of Mn, Zn and Cu is increased by taking food plus supplements. Some of botanical or animal origin supplements have been reported to contain high concentrations of Mn, Zn and Cu. We investigated the effects of long-term exposure to Mn, Zn and Cu on learning and memory in aged mice. 20-week-old ICR-JCL male mice were given 100 ppm Mn, Zn or Cu via drinking water for 58 weeks. The effects of Mn, Zn and Cu on non-spatial long-term memory were investigated using step-through-type passive avoidance task in male aged mice after 56-weeks administration. In the retention trials of the passive avoidance test, latencies to enter a dark compartment were shorter in the Mn- and Cu-exposed mice, compared to control mice. The behavioral test indicated the possibility that long-term exposure to Mn and Cu inhibited long-term memory.