Mistlberger R E, Rechtschaffen A
Physiol Behav. 1985 Jan;34(1):17-22. doi: 10.1016/0031-9384(85)90070-8.
Entrainment of tilt-cage measured circadian activity rhythms to a 2 hr daily period of water availability was assessed in rats fed either an oil-chow mash, which rats readily consume in the absence of water, or dry pellet chow, which rats less readily consume in the absence of water. Four of 6 pellet fed rats but only 2 of 14 mash fed rats exhibited entrainment to water access. Periodic water availability, unlike periodic food availability, thus does not appear to be a potent zeitgeber for circadian activity rhythms in the rat. The entrainment that does occur in some rats may result from shifting of food intake to coincide with the availability of water.
在喂食油拌饲料（大鼠在无水情况下很容易食用）或干颗粒饲料（大鼠在无水情况下不太容易食用）的大鼠中，评估了倾斜笼测量的昼夜活动节律与每天2小时供水期的同步情况。6只喂食颗粒饲料的大鼠中有4只，但14只喂食油拌饲料的大鼠中只有2只表现出对供水的同步。因此，与周期性食物供应不同，周期性供水似乎不是大鼠昼夜活动节律的有效授时因子。在一些大鼠中确实发生的同步可能是由于食物摄入时间的改变以与供水时间一致。
