King T E, Joynes R L, Meagher M W, Grau J W
Department of Psychology, Texas A&M University, College Station 77843, USA.
J Exp Psychol Anim Behav Process. 1996 Jul;22(3):265-78. doi: 10.1037//0097-7403.22.3.265.
Shocked rats (Rattus norvegicus) often exhibit longer tail withdrawal latencies to radiant heat, which suggests that exposure to shock reduces pain. But at the same time, rats appear hyperreactive to shock, suggesting than pain is enhanced. Experiment 1 replicated these findings and showed that when tail movement was monitored, shocked rats were less responsive to heat and hyperreactive to shock even when the same behavioral criteria were used. When latency to vocalize was measured, shocked rats appeared hyperreactive to both test stimuli (Experiments 2 and 3). Prior exposure to shock also enhanced the acquisition of conditioned fear in a different context (Experiment 4) and the speed with which rats learned a response to avoid a thermal stimulus (Experiment 5). The results suggest that exposure to shock enhances pain.
受到电击的大鼠（褐家鼠）对辐射热的尾巴缩回潜伏期通常更长，这表明遭受电击会减轻疼痛。但与此同时，大鼠对电击似乎反应过度，这表明疼痛增强了。实验1重复了这些发现，并表明在监测尾巴运动时，即使使用相同的行为标准，受到电击的大鼠对热的反应也较弱，而对电击反应过度。在测量发声潜伏期时，受到电击的大鼠对两种测试刺激似乎都反应过度（实验2和3）。先前遭受电击还增强了在不同环境中条件性恐惧的习得（实验4）以及大鼠学习避免热刺激反应的速度（实验5）。结果表明，遭受电击会增强疼痛。
