Servatius R J, Ottenweller J E, Natelson B H
Program in Neuroscience, Department of Psychology, Princeton University, NJ, USA.
Biol Psychiatry. 1995 Oct 15;38(8):539-46. doi: 10.1016/0006-3223(94)00369-E.
Posttraumatic stress disorder (PTSD) may occur in humans exposed chronically to stressors or after a single exposure to a traumatic event. A distinguishing feature of patients with PTSD is an exaggerated startle response, evident long after the traumatic event. We have observed similar abnormalities in our animal model of a chronic stress state. Rats exposed to 3 days (3DS) of our stress regimen (2-hr sessions of 40, 2 mA tailshocks) have exhibited a consistent pattern of persistent physiological and behavioral abnormalities including an exaggerated startle response several days after stressor cessation. In contrast, rats exposed to a single stress session (1DS) have exhibited many, but not all, of the persistent abnormalities displayed by 3DS rats. The present experiment compared the startle responding of 3DS and 1DS rats 4, 7, and 10 days after stressor cessation. Consistent with previous work, stressed rats exhibited elevated basal plasma corticosterone (CORT) levels the first day poststressor. These CORT levels were sensitive to the number of stressor exposures with higher CORT levels in 3DS rats than in 1DS rats. As for startle responding, the 1DS rats exhibited an exaggerated startle response 7 days poststressor, whereas startle sensitization was apparent 10 days poststressor in 3DS rats. Thus, the appearance of an exaggerated startle response after stressor cessation appears to be related to the number of stress session exposures. These animal models, the 3DS and 1DS rats, may be useful to gain insight into the neurobehavioral changes associated with PTSD.
创伤后应激障碍（PTSD）可能发生在长期暴露于应激源的人群中，或单次经历创伤性事件之后。PTSD患者的一个显著特征是夸张的惊吓反应，在创伤事件很久之后仍很明显。我们在慢性应激状态的动物模型中观察到了类似的异常情况。暴露于我们的应激方案（每天2小时，40次、每次2毫安的尾部电击，共3天，即3DS）的大鼠表现出持续的生理和行为异常模式，包括在应激源停止几天后出现夸张的惊吓反应。相比之下，暴露于单次应激（1DS）的大鼠表现出了3DS大鼠所显示的许多但并非全部的持续性异常。本实验比较了应激源停止后4天、7天和10天3DS和1DS大鼠的惊吓反应。与之前的研究一致，应激大鼠在应激源停止后的第一天基础血浆皮质酮（CORT）水平升高。这些CORT水平对应激源暴露次数敏感，3DS大鼠的CORT水平高于1DS大鼠。至于惊吓反应，1DS大鼠在应激源停止后7天表现出夸张的惊吓反应，而3DS大鼠在应激源停止后10天惊吓反应敏感化明显。因此，应激源停止后夸张惊吓反应的出现似乎与应激次数有关。这些动物模型，即3DS和1DS大鼠，可能有助于深入了解与PTSD相关的神经行为变化。
