Yi I, Stephan F K, Bays M E
Department of Psychology, Florida State University, Tallahassee 32306-1051, USA.
Physiol Behav. 1995 Jul;58(1):67-73. doi: 10.1016/0031-9384(95)90578-u.
Rats housed in activity wheels (A-W) or hanging cages (H-C) received food restriction to 4 h/day for 15 days. Food was given at fixed times to entrain the feeding entrainable oscillator or at irregular times to prevent entrainment. One half of the rats received food in the light phase, the other half in the dark phase of the light-dark cycle. Food was then reduced to 6 g/day for 4 days for A-W rats or 7 days for H-C rats. Stomachs were removed 24 h after the last meal and the ulcerated area was quantified. Twenty one of 32 A-W rats and 19 of 32 H-C rats had ulcers in the glandular stomach. Ulcers were significantly larger in A-W rats (p < 0.01). Activity levels (in A-W rats), % body weight loss and terminal body weight (in both groups) were significantly correlated with the area of ulcers. There was no significant time of day effect on the ulcer severity. However, an unexpected finding was that for A-W rats, those fed at fixed times had larger ulcers than those fed at irregular times (p < 0.01) while H-C rats showed an expected trend in the opposite direction. One possible explanation for this result is that for A-W rats, the reduced food supply at an expected time of day generated a greater stress response than in rats whose feeding time was unpredictable.
饲养在活动轮（A-W）或悬挂笼（H-C）中的大鼠接受为期15天的每日4小时食物限制。食物在固定时间给予以同步进食可同步振荡器，或在不规律时间给予以防止同步。一半大鼠在明暗周期的光照阶段进食，另一半在黑暗阶段进食。然后，A-W组大鼠在4天内将食物量减少至每天6克，H-C组大鼠在7天内将食物量减少至每天6克。在最后一餐24小时后取出胃，对溃疡面积进行量化。32只A-W大鼠中有21只、32只H-C大鼠中有19只腺胃出现溃疡。A-W组大鼠的溃疡明显更大（p<0.01）。活动水平（A-W组大鼠）、体重减轻百分比和终末体重（两组）与溃疡面积显著相关。溃疡严重程度没有明显的昼夜效应。然而，一个意外发现是，对于A-W组大鼠，定时喂食的大鼠溃疡比不定时喂食的大鼠更大（p<0.01），而H-C组大鼠则呈现相反的预期趋势。这一结果的一个可能解释是，对于A-W组大鼠，在一天中预期时间减少食物供应比喂食时间不可预测的大鼠产生了更大的应激反应。
