Bauman R A, Widholm J J, Ghosh S, Kant G J
Division of Neurosciences, Walter Reed Army Institute of Research, Washington DC 20307-5100, USA.
Physiol Behav. 1998 Jun 15;64(4):507-12. doi: 10.1016/s0031-9384(98)00102-4.
The effects of sustained stress on acquisition and performance of a delayed alternation task were studied in male rats. Rats lived 24 h per day in operant cages where they earned all of their food via lever pressing. During the stress portion of each experiment, one group of rats was able to avoid or escape signaled intermittent footshock (Avoidance/Escape group), a second group (Yoked) did not have control over shock termination, a third group never received shock (Control). Shock trials were presented around-the-clock at approximately 5-min intervals and the stress portion of each study lasted 1 week. We have previously reported that rats tolerate this paradigm well and avoid/escape 99% of the shock trials. Three experiments were conducted. In Experiment 1, rats learned the delayed alternation task prior to stress onset; in Experiment 2, rats were exposed to stress and the alternation task concurrently; in Experiment 3, rats were stressed for 14 days prior to being required to perform the delayed alternation task. In the first experiment, stress decreased both food intake and the accuracy of responding during the first days of stress. In the second experiment (acquisition), stressed rats required more days to reach asymptotic performance on the alternation task. In Experiment 3, rats stressed for 14 days prior to acquisition of the delayed alternation task performed similarly to controls.
研究了持续应激对雄性大鼠延迟交替任务的习得和表现的影响。大鼠每天24小时生活在操作箱中，通过按压杠杆获取所有食物。在每个实验的应激阶段，一组大鼠能够避免或逃脱有信号提示的间歇性足部电击（回避/逃脱组），第二组（配对组）无法控制电击终止，第三组从未接受过电击（对照组）。电击试验全天每隔约5分钟进行一次，每项研究的应激阶段持续1周。我们之前曾报道，大鼠能很好地耐受这种模式，并能在99%的电击试验中避免/逃脱。进行了三项实验。在实验1中，大鼠在应激开始前学习延迟交替任务；在实验2中，大鼠同时接受应激和交替任务；在实验3中，大鼠在被要求执行延迟交替任务前应激14天。在第一个实验中，应激在应激开始的头几天降低了食物摄入量和反应准确性。在第二个实验（习得实验）中，应激大鼠在交替任务上达到渐近表现需要更多天数。在实验3中，在习得延迟交替任务前应激14天的大鼠表现与对照组相似。
