de Castro J M
Department of Psychology, Georgia State University, University Plaza, Atlanta 30303.
Physiol Behav. 1988;43(6):739-46. doi: 10.1016/0031-9384(88)90371-x.
In order to investigate whether an observed difference in the meal patterns of rats and human may be due to constraints that humans have on the timing of meals and their large but infrequent meal pattern, rats had similar constraints imposed on their meal intake. Fifteen male Long-Evans rats were monitored in five individual enclosed chambers equipped with pellet sensing eatometers for three fourteen-day data collection periods. Both groups were monitored in a baseline ad lib condition, then one group (n = 7) was allowed access to food only once every two hours, while the second group (n = 8) was allowed to access only five times per day. Both groups were then monitored for a second ad lib baseline period. The imposition of both schedules reduced meal frequencies and estimated premeal stomach contents, and increased meal sizes and estimated postmeal stomach contents. The imposition of the five meal per day, but not the twelve meal per day schedule of meal access, eliminated the significant relationships between meal size and the postmeal interval evident during baseline conditions and produced significant relationships between meal size and the premeal interval and estimated premeal stomach content, not seen during baseline conditions. The rats under the five meal per day access schedule showed a preprandial pattern of intake very similar to that previously observed in humans eating ad lib. It was concluded that the preprandial pattern, typical of humans, is characteristic of intake involving large infrequent meals which produce stomach filling to an upper limiting threshold. The postprandial pattern, typical of rats, is characteristic of intake involving small frequent meals that are initiated when the stomach empties to a lower threshold. A peripheral, stomach capacity, model then, can be used to explain both the preprandial and the postprandial patterns. Which pattern is used depends upon environmental conditions.
为了研究观察到的大鼠和人类进食模式差异是否可能归因于人类对进食时间的限制以及他们大量但不频繁的进食模式，对大鼠的进食摄入施加了类似的限制。15只雄性Long-Evans大鼠在五个单独的封闭实验舱中进行监测，这些实验舱配备了颗粒感应进食计量仪，进行三个为期14天的数据收集期。两组均在自由进食的基线条件下进行监测，然后一组（n = 7）每两小时仅被允许进食一次，而第二组（n = 8）每天仅被允许进食五次。然后两组再次在自由进食的基线期进行监测。两种进食时间表的实施均降低了进食频率并估计了餐前胃内容物，同时增加了进食量并估计了餐后胃内容物。每天五次进食时间表的实施，但不是每天十二次进食时间表的实施，消除了基线条件下明显的进食量与餐后间隔之间的显著关系，并产生了进食量与餐前间隔以及估计的餐前胃内容物之间的显著关系，这在基线条件下未观察到。每天五次进食时间表下的大鼠表现出一种餐前进食模式，与之前观察到的自由进食的人类非常相似。得出的结论是，人类典型的餐前模式是涉及大量不频繁进食并使胃充满至上限阈值的进食特征。大鼠典型的餐后模式是涉及小而频繁进食的特征，这种进食在胃排空至较低阈值时开始。因此，一种外周的胃容量模型可用于解释餐前和餐后模式。使用哪种模式取决于环境条件。
