Bhatnagar S, Vining C, Iyer V, Kinni V
Department of Anaesthesiology, Abranson Building Ste. 402, Children's Hospital of Philadelphia, 34th & Civic Center Boulevard, Philadelphia, PA 19104, USA.
J Neuroendocrinol. 2006 Jan;18(1):13-24. doi: 10.1111/j.1365-2826.2005.01375.x.
These present studies aimed to compare changes in hypothalamic-pituitary-adrenal (HPA) activity and body temperature in response to acute social defeat, to repeated social stress and to novel restraint after repeated stress, as well as to assess effects on metabolic parameters by measuring body weight gain and food and water intake. We found that social defeat produced a marked increase in both adrenocorticotrophic hormone and corticosterone compared to placement in a novel cage. Similarly, body temperature was also increased during social defeat and during 30 min of recovery from defeat. We then examined the effects of 6 days of repeated social stress and observed minimal HPA responses to repeated social stress compared to control rats. These neuroendocrine responses were contrasted by robust increases in body temperature during stress and during recovery from stress during 6 days of repeated stress. However, in response to novel restraint, repeatedly stressed rats displayed facilitated body temperature responses compared to controls, similar to our previous findings with HPA activity. Food intake was increased during the light period during which defeat took place, but later intake during the dark period was not affected. Repeated stress decreased body weight gain in the dark period but food intake was increased overall during the 6 days of repeated stress in the light period. As a result, repeated stress increased cumulative food intake during the light period in the stressed rats but these relatively small increases in food intake were unable to prevent the diminished total weight gain in repeatedly stressed rats. Overall, the results demonstrate that, although acute social defeat has similar effects on temperature and HPA activity, repeated exposure to social stress has divergent effects on HPA activity compared to body temperature and that dampened weight gain produced by repeated social stress cannot be fully explained by changes in food intake.
这些当前的研究旨在比较下丘脑-垂体-肾上腺（HPA）活性和体温在急性社会挫败、重复社会应激以及重复应激后的新奇束缚刺激下的变化，同时通过测量体重增加、食物和水摄入量来评估对代谢参数的影响。我们发现，与置于新笼中相比，社会挫败导致促肾上腺皮质激素和皮质酮均显著增加。同样，在社会挫败期间以及挫败后30分钟的恢复过程中，体温也会升高。然后，我们研究了6天重复社会应激的影响，发现与对照大鼠相比，重复社会应激对HPA的反应最小。这些神经内分泌反应与重复应激6天期间应激及应激恢复过程中体温的强劲升高形成对比。然而，对于新奇束缚刺激，与对照组相比，反复应激的大鼠表现出更明显的体温反应，这与我们之前关于HPA活性的研究结果相似。在发生挫败的光照期食物摄入量增加，但随后黑暗期的摄入量未受影响。重复应激在黑暗期降低了体重增加，但在光照期重复应激的6天中总体食物摄入量增加。结果，重复应激增加了应激大鼠在光照期的累积食物摄入量，但这些相对较小的食物摄入量增加无法阻止反复应激大鼠总体体重增加的减少。总体而言，结果表明，尽管急性社会挫败对体温和HPA活性有相似影响，但与体温相比，反复暴露于社会应激对HPA活性有不同影响，并且反复社会应激导致的体重增加减少不能完全由食物摄入量的变化来解释。
