Mistlberger R E, Houpt T A, Moore-Ede M C
Department of Physiology and Biophysics, Harvard Medical School, Boston, MA.
Neurobiol Aging. 1990 Nov-Dec;11(6):619-24. doi: 10.1016/0197-4580(90)90027-w.
Twenty-four hour schedules of restricted food availability entrain a component of the circadian activity rhythm in rats via a food-entrainable pacemaker separate from the light-entrainable pacemaker. The effect of aging on food-entrained circadian rhythms was examined in 6 rats maintained on a restricted diurnal feeding schedule from age 3-21 months and again from 24-25 months. Food-entrainment, measured as behavioral anticipation of a 1-hr daily mealtime during the middle of the light period and persistence of this anticipation rhythm during food deprivation, was apparent in the aged rats when recorded in wheel-running cages from 20-21 months of age. Despite the long duration of restricted diurnal food diurnal food access, the aged rats, like young rats, rapidly to nocturnal activity when transferred to ad lib feeding. When restricted diurnal feeding was reinstated at 24 months age, these rats, now recorded in food-bin monitoring cages, required more time for a food anticipation pattern to emerge and showed a lower amplitude food anticipation rhythm compared to a group of young adult rats. These age-related changes are similar to those that characterize photically entrained circadian rhythms and suggest that both components of the rat's multioscillatory circadian timekeeping system deteriorate in parallel over the life span.
24小时限时进食时间表通过一个与光驱动起搏器分开的食物驱动起搏器，使大鼠的昼夜活动节律产生一个组成部分。在6只大鼠中研究了衰老对食物驱动的昼夜节律的影响，这些大鼠从3至21月龄以及再次从24至25月龄开始维持限时昼夜进食时间表。食物驱动，通过在光照期中间对每日1小时进餐时间的行为预期以及在食物剥夺期间这种预期节律的持续存在来衡量，在20至21月龄的老年大鼠中，当在转轮笼中记录时是明显的。尽管限时昼夜食物获取的持续时间很长，但老年大鼠与年轻大鼠一样，在转为自由进食时迅速转变为夜间活动。当在24月龄恢复限时昼夜进食时，这些现在在食物箱监测笼中记录的大鼠，与一组年轻成年大鼠相比，需要更多时间才能出现食物预期模式，并且表现出较低幅度的食物预期节律。这些与年龄相关的变化类似于那些表征光驱动昼夜节律的变化，并表明大鼠多振荡器昼夜计时系统的两个组成部分在整个生命周期中并行衰退。
