Stewart K T, Rosenwasser A M, Levine J D, McEachron D L, Volpicelli J R, Adler N T
Department of Psychology, University of Pennsylvania, Philadelphia 19104.
Physiol Behav. 1990 Jul;48(1):157-64. doi: 10.1016/0031-9384(90)90277-b.
Two studies explore the relationship between rhythmicity and behavioral depression. Behavioral depression was induced using inescapable footshock, and assessed by measuring subsequent responses to escapable shock, in rats housed under different light-dark conditions. Experiment 1 compared escape performance in free-running and entrained animals following inescapable shock. Free-running and entrained animals did not exhibit differential vulnerability to the effects of inescapable shock. In addition, there were no systematic effects on phase following shock. However, several free-running animals showed increased circadian period following shock, and lengthening of period was significantly correlated with escape performance. Individual differences in baseline period or phase were not predictive of escape performance. In Experiment 2, "aftereffects" of entrainment to long or short light-dark cycles were utilized to create groups of animals with long or short free-running periods. After the administration of inescapable shock, escape performance was tested. There were no significant differences among experimental groups in escape performance. These results suggest that plasticity of circadian period, but not baseline period per se, may be associated with the ability to adapt to environmental challenges.
两项研究探讨了节律性与行为性抑郁之间的关系。采用不可逃避的足部电击诱导大鼠产生行为性抑郁，并通过测量其随后对可逃避电击的反应，对处于不同明暗条件下饲养的大鼠进行评估。实验1比较了不可逃避电击后自由活动和节律受调节的动物的逃避表现。自由活动和节律受调节的动物对不可逃避电击的影响未表现出不同的易感性。此外，电击后对相位没有系统性影响。然而，几只自由活动的动物在电击后昼夜节律周期延长，且周期延长与逃避表现显著相关。基线周期或相位的个体差异不能预测逃避表现。在实验2中，利用对长或短明暗周期的节律调节“后效应”来创建自由活动周期长或短的动物组。给予不可逃避电击后，测试逃避表现。各实验组在逃避表现上没有显著差异。这些结果表明，昼夜节律周期的可塑性而非基线周期本身，可能与适应环境挑战的能力有关。
