Stephan F K
Physiol Behav. 1984 Apr;32(4):663-71. doi: 10.1016/0031-9384(84)90323-8.
Rats anticipate daily 2 hr meals with a sharp increase in activity several hours prior to food availability. The present experiment examined the response to phase shifts of food access in rats with lesions of the suprachiasmatic nuclei (SCN). Following entrainment of activity to 2 hr of food per day, food access was phase delayed or phase advanced by 4, 6, or 8 hr. All rats responded to phase delays of 4 or 6 hr with an increase in the duration of anticipatory activity so that transients appeared mostly in activity onset. Following 8 hr phase delays, clear delaying transients in both activity onset and end were observed. Only a few rats showed advancing transients in activity after phase advances of food access. In response to 6 hr and 8 hr phase advances, 3 different responses occurred: (a) activity re-entrained to food access by the 2nd or 3rd day without clear intervening transients, (b) activity phase shifted by means of distinct delaying transients and (c) delaying transients occurred in one component of activity while a second component of activity appeared at the new phase position by the second or third day. These results provide further evidence that anticipation of food access is mediated by a circadian mechanism which is functionally independent of the SCN and illustrate some similarities as well as considerable differences between circadian rhythms entrained by feeding and those entrained by light-dark cycles.
大鼠每天预期有2小时的进食时间，在食物供应前数小时活动会急剧增加。本实验研究了视交叉上核（SCN）损伤的大鼠对进食时间相位变化的反应。在将活动节律调整为每天2小时进食后，将进食时间相位延迟或提前4、6或8小时。所有大鼠对4或6小时的相位延迟反应是预期活动持续时间增加，因此瞬变主要出现在活动开始时。在8小时相位延迟后，观察到活动开始和结束时都有明显的延迟瞬变。只有少数大鼠在进食时间相位提前后活动出现提前瞬变。对于6小时和8小时的相位提前，出现了3种不同的反应：（a）活动在第2天或第3天重新与进食时间同步，没有明显的中间瞬变；（b）活动通过明显的延迟瞬变进行相位移动；（c）延迟瞬变出现在活动的一个成分中，而活动的第二个成分在第2天或第3天出现在新的相位位置。这些结果进一步证明，对进食时间的预期是由一种昼夜节律机制介导的，该机制在功能上独立于SCN，并说明了由进食诱导的昼夜节律与由明暗周期诱导的昼夜节律之间的一些相似之处以及显著差异。
