Animal model of brain aging: Senescence-accelerated mouse (SAM)

Abstract

SAMP8 mice show age-related deficits in avoidance and spatial learning tasks, and also exhibit reduced anxiety-like behavior in the food neophobia, elevated plus-maze, and punished water-licking tests. The emotional change in SAMP8 is considered to be closely related to the deficits in learning tasks. Aged SAMR1 show similar behavioral changes to those in SAMP8 mice, indicating that some of behavioral changes in SAMP8 may be derived from accelerated aging. SAMP10 mice exhibit marked behavioral depression when they are subjected to the tail suspension test or the forced swimming test. The SAMP10 strain may be useful for studying age-related behavioral depression and reduced spontaneity, and can be used as an animal model for the development of therapeutic drugs for age-related depression and reduced spontaneity. SAMP8 and SAMP10 have also a marked disorder of circadian rhythms of SMA and drinking behavior. Bright light stimulation ameliorates the abnormal circadian rhythm of SMA. SAMP8 reentrained more rapidly than SAMR1, when they were shifted from the DD cycle to the LD cycle. These findings suggest that SAMP8 and SAMP10 are also valid animal models for age-related disorders of circadian rhythms that occur in elderly people and patients with senile dementia.