Effect of chronic restraint on open field activity of aging C57BL/6N mice.

Eight, 20, and 31 month old male C57BL/6N mice were exposed to three 24-hour restraint sessions per week, or to a nontreatment condition. All mice received five 2-minute open field tests after 5 and after 6 weeks of treatment. The activity of restrained mice tended to be greater than that of nonrestrained animals. In general, 8 month old mice were more active than older subjects. Age related activity decrements were prominent in the first series of open field tests, while restraint effects were most pronounced in the second series.