Dose physical exercise prevent neuronal cell death induced by chronically psychological stress?

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17500442
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Sports science
• Research Institution: Nippon Medical School
• Principal Investigator: MIKAMI Toshio Nippon Medical School, Faculty of Medicine, Associate Professor, 医学部, 助教授 (60199966)
• Co-Investigator(Kenkyū-buntansha): OHTA Shigeo Nippon Medical School, Graduate School of Medicine, Professor, 大学院・医学研究科, 教授 (00125832)
• Project Period (FY): 2005 – 2006
• Keywords: stress / exercise / spatial memory / IGF-1 / IGF-1 receptor / JB-1 / water maze test / hippocampus

Research Abstract

[2006] [Purpose] We investigated whether physical exercise would maintain cognitive performance impaired by psychological stress. [Method] LID mice, which had the decreased level of plasma insulin like-growth factor-1 (IGF-1), were divided into following three groups. Group 1: The mice were fed in the small cage. Group 2: The mice were fed in the small cage with an hour of treadmill running 5 days per a week. Group 3: The mice were fed in normal cage. The mice were fed as above condition for 4 weeks. After then, the spatial memory of the mice was measured by Morris water maze test (MWT). [Results] Feeding in the small cage resulted in the decrease of spatial memory compared with the normal feeding. However, treadmill running prevented the decrease of spatial memory.
[2007] [Purpose] We investigated whether stress-induced suppression of spatial memory was related to the uptake of IGF-1 into brain. [Method] C57BL/6 mice were divided into 4 groups and fed for 4 weeks as follows. (1) Stressed group: The mice were fed in small cage with 6 h of immobilization per a day. (2) Exercise group: The mice were fed in small cage with 6 hours of immobilization and an hour of treadmill running per a day. (3) JB-1 group: The mice infused JB-1, inhibitor of IGF-1 receptor, using an osmotic pump implanted into back, were fed in small cage with 6 h of immobilization and an hour of treadmill running per day. (4) Control group: The mice were fed in normal cage. [Results] Four weeks of chronic stress caused by small cage feeding and immobilization resulted in the decrease of spatial memory while treadmill running prevent it. On the other hand, administration of JB-1 made the advantage of exercise ineffective.
[Conclusion] These findings suggested that the preventive effect of exercise on spatial memory is closely related the uptake of IGF-1 into brain