White W, Timberlake W
Department of Psychology, Indiana University, Bloomington 47405, USA.
Physiol Behav. 1999;65(4-5):625-42. doi: 10.1016/s0031-9384(98)00211-x.
Large meals scheduled at greater-than-circadian periods (such as T = 31 h) tend to elicit enhanced activity approximately 24 h subsequent to receipt. These studies characterized the process responsible for this meal-engendered "circadian ensuing activity" (meal CEA). Female Sprague-Dawley rats were housed in stations containing a running wheel, pellet dispenser, and lights. Young, middle-aged, or suprachiasmatic-nucleus (SCN)-lesioned rats were given two 1-h meals every 31 or 34 h. Meals were separated by alternating short and long fasts. Most young intact rats engaged in enhanced activity approximately 24 h subsequent to the start of the two-meal series. This circadian ensuing activity underwent large, abrupt daily displacements in response to daily meal delays, was manifested to some degree at all times of day, had an amplitude that was modulated by circadian time of day, was attenuated in middle-aged rats, was evident in SCN-lesioned rats, and oscillated following termination of the feeding schedule. A single experience with food at a novel time of day can "reset" an SCN-independent oscillating process responsible for a circadian activity pattern. CEA has features not readily accommodated by present models of "food-anticipatory activity." The readiness with which the process can be reset implies a keen sensitivity to shifts in the time of food availability but could also produce aberrant behavioral patterns. A T >> 24-h feeding schedule appears to be an ideal procedure with which to study the specific food-related factors responsible for resetting circadian processes and producing a subsequent reallocation of daily activity.
安排在大于昼夜节律周期（如T = 31小时）时的大餐往往会在进食后约24小时引发活动增强。这些研究描述了导致这种由进食引起的“昼夜节律后续活动”（进食CEA）的过程。将雌性Sprague-Dawley大鼠饲养在装有跑步轮、颗粒饲料分配器和灯光的笼子里。给年轻、中年或视交叉上核（SCN）损伤的大鼠每31或34小时喂食两顿，每顿1小时。两餐之间通过交替短时间和长时间禁食隔开。大多数年轻未损伤的大鼠在两餐系列开始后约24小时会出现活动增强。这种昼夜节律后续活动会因每日进食延迟而发生大幅度、突然的每日位移，在一天中的所有时间都有一定程度的表现，其振幅受昼夜节律时间调节，在中年大鼠中减弱，在SCN损伤的大鼠中也很明显，并且在喂食计划终止后会振荡。在一天中一个新的时间点单次进食经历可以“重置”一个与SCN无关的振荡过程，该过程负责昼夜节律活动模式。进食CEA具有当前“食物预期活动”模型难以解释的特征。该过程易于重置意味着对食物供应时间的变化非常敏感，但也可能产生异常的行为模式。T >> 24小时的喂食计划似乎是研究负责重置昼夜节律过程并导致后续每日活动重新分配的特定食物相关因素的理想程序。
