Servatius R J, Ottenweller J E, Bergen M T, Soldan S, Natelson B H
Department of Neuroscience, New Jersey Medical School, East Orange.
Physiol Behav. 1994 Nov;56(5):945-54. doi: 10.1016/0031-9384(94)90328-x.
We assessed the functional adrenocortical and behavioral state of rats previously exposed to repeated stressor presentations. In Experiment 1, the whole-body startle response to threshold (91 dB) and suprathreshold (96 dB) stimuli was assessed in rats given 3 daily sessions (3DS) of 40, 2-mA tailshocks. The 3DS rats showed an exaggerated startle response to the threshold auditory stimulus 4 days poststressor compared to nonshocked controls (CON). An exaggerated startle response in stressed rats was not evident either 1 day or 10 days poststressor. In Experiment 2, adrenocortical sensitization and behavioral reactivity were assessed in rats exposed to 1 day (1DS) or 3 days of our stress regimen. Stressed rats exhibited elevated basal plasma corticosterone (CORT) levels 1 day poststressor which recovered by 9 days poststressor. Stressed rats also exhibited suppressed open-field activity 4 days poststressor. On the 10th day poststressor, rats were exposed to a single tailshock. The 1DS and 3DS rats showed both a sensitized and prolonged CORT response to stressor reexposure compared to control rats which received only the single tailshock. In addition, on the 11th day poststressor 3DS rats exhibited a moderate recapitulation of the elevated basal CORT levels seen after the initial stressor exposures. Thus, exposure to our stress regimen produces a chronic stress state in rats characterized by persistent behavioral and adrenocortical sensitization, as well as suppressed open-field activity and elevated basal CORT levels. Rats exhibiting a chronic stress state may be appropriate as a model for the study of stress-related psychophysiological illnesses, such as posttraumatic stress disorder.
我们评估了先前反复暴露于应激源的大鼠的肾上腺皮质功能和行为状态。在实验1中，对每天接受3次（3DS）、每次40次、2毫安尾部电击的大鼠，评估其对阈值（91分贝）和超阈值（96分贝）刺激的全身惊吓反应。与未受电击的对照组（CON）相比，3DS组大鼠在应激源刺激后4天对阈值听觉刺激表现出夸张的惊吓反应。应激大鼠在应激源刺激后1天或10天，夸张的惊吓反应并不明显。在实验2中，对暴露于1天（1DS）或3天应激方案的大鼠进行肾上腺皮质致敏和行为反应性评估。应激大鼠在应激源刺激后1天表现出基础血浆皮质酮（CORT）水平升高，在应激源刺激后9天恢复。应激大鼠在应激源刺激后4天也表现出旷场活动受到抑制。在应激源刺激后第10天，大鼠接受单次尾部电击。与仅接受单次尾部电击的对照大鼠相比，1DS和3DS组大鼠对应激源再次暴露均表现出致敏和延长的CORT反应。此外，在应激源刺激后第11天，3DS组大鼠中度重现了初始应激源暴露后出现的基础CORT水平升高。因此，暴露于我们的应激方案会使大鼠产生慢性应激状态，其特征为持续的行为和肾上腺皮质致敏，以及旷场活动受到抑制和基础CORT水平升高。表现出慢性应激状态的大鼠可能适合作为研究与应激相关的心理生理疾病（如创伤后应激障碍）的模型。
