Effects of Unpredictable and Uncontrollable Aversive Stimulus upon Long-term Adaptive Behavior in Rats

采用KGbox-24两个实验箱，研究了可预测/不可预测的电刺激对大鼠长期适应行为的影响。在每个实验中，大鼠成对运行，并在20天内每天24小时以VT-6分钟的时间对一对大鼠进行短暂的不可避免的电击。对每对中的一只大鼠，电击前总是有1分钟的声音，但对另一只大鼠，电击前没有信号。在这个应激阶段之前是8-10天的基线阶段，在此期间没有电击。KGbox-24在12:12-h明暗循环条件下，以1 min为单位连续测量大鼠的进食、饮水、运动和饲养情况。三个实验性质基本相同，但在实验2和实验3中，制备了一个家庭笼对照组，每天中午测量无电击对照组大鼠的体重。在实验箱中运行的大鼠的体重也被平均下来，每天中午时分，将它们暂时从箱中取出。实验2和实验3中，应激期KGbox-24大鼠的体重较无冲击家笼大鼠明显下降。在所有三个实验中，在实验箱里跑的老鼠中，受到可预测电击的老鼠比受到不可预测电击的老鼠体重减轻的相对更多。可预测的冲击比不可预测的冲击带来更大的压力，这一事实与通常在短期实验中发现的相反效果形成鲜明对比。但事实与Abbott et al（1984）最近提出的建议是一致的，他区分了可预测/不可预测冲击对压力的短期影响和长期影响。对其他行为更详细的分析结果在其他地方给出。可控/不可控电击对大鼠长期适应行为影响的研究本来是有计划的，但由于时间紧张没有进行。少

The effects of predictable/unpredictable grid-shocks upon rats' long-term adaptive behavior were studied in three experiments using two boxes named KGbox-24. In each experiment, rats were run in a pair and brief inescapable shocks were given to both rats of a pair with a VT-6 min schedule over 24 hours a day for 20 days. To one rat of each pair, shocks were always given preceded by a 1-min tone, but to the other rat, shocks were given unsignaled. This stress phase was preceded by a baseline phase of 8-10 days, during which no shocks were given. In the KGbox-24, eating and drinking, as well as locomotion and rearing, of rats were continuously measured in 1-min units under the condition of 12:12-h light:dark cycle. All three experiments were of essentially the same nature, but in Experiments 2 and 3, a home-cage control group was prepared and the body weight of shock-free control rats was measured daily at the noon time. The body weight of rats run in the experimental boxes was also meas … More ured daily at the noon time, taking them out temporarily from the boxes.In Experiments 2 and 3, the hody weight of rats run in the KGbox-24 decreased substantially during the stress phase compared with that of those kept in the shock-free home cages. Of those run in the experimental boxes, rats exposed to the predictable shocks lost relatively more body weight than those exposed to the unpredictable shocks in all three experiments. This fact of greater stressfulness of predictable shocks over unpredictable shocks contrasts sharply with the opposite effect usually found in short-term experiments. But the fact is in line with the suggestion made recently by Abbott et al (1984) who distinguished the short-term effects and long-term effects of predictable/unpredictable shocks upon stress. The results of more detailed analyses of other behaviors are presented elsewhere.A study on the effects of controllable/uncontrollable shocks upon long-term adaptive behavior of rats had been originally planned but was not conducted because of shortage of time. Less