抄録
Purpose of this study was to investigate whether protective effect of exercise on stress-induced impairment of spatial memory may be dependent on insulin-like growth factor 1(IGF-1). Male C57BL/6 mice were divided into four groups; control, immobilized, exercised and JB1-administrated mice. Control mice were fed in normal cage without immobilization and exercise. Immobilized, exercised and JB1-administrated mice were individually fed in small cage and exposed to 8 h of immobilization 6 days per week. Exercised and JB1-administrated mice were performed 1 h of treadmill running 6 days per week. All of mice were implanted osmotic pump that contained JB1, antagonist for IGF-1 receptor, in JB1-administrated mice and saline in control, immobilized and exercised mice. Four weeks later, spatial learning was measured by Morris water maze test. After water maze test, brains of mice were excised under anesthesia and used for immuohistochemical analysis with antibody of Ki67, which is neurogenesis marker. Chronic immobilization impaired spatial memory and suppressed Ki67-positive cells in dentate gyrus of hippocampus. Exercise prevented impairment of spatial memory and suppression of Ki67-positive cells, while JB1 canceled protective effect of exercise on spatial memory and numbers of Ki67-positive cells. These findings suggested that protective effects of exercise on stress-induced impairment of spatial memory were dependent on IGF-1. [J Physiol Sci. 2008;58 Suppl:S142]
