Suchecki D, Nelson D Y, Van Oers H, Levine S
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, California 94305, USA.
Psychoneuroendocrinology. 1995;20(2):169-82. doi: 10.1016/0306-4530(94)00051-b.
These studies investigated the activation and inhibition (negative feedback) of the neonatal rat. The ACTH response of maternally deprived pups is persistently elevated for 30 min, suggesting a deficiency in the negative feedback system. In Experiment 1, we examined the time-course of corticosterone (CORT) and ACTH responses to a saline injection over a 120-min period during development. In deprived pups, CORT and ACTH were persistently elevated throughout the testing period, whereas only 15-day-old nondeprived pups showed ACTH and CORT elevations. Further nondeprived and deprived pups were exposed twice to ether (Experiment 2) or saline injections (Experiment 3) separated by a 1-h interval. Nondeprived pups showed an augmented ACTH response to double exposure to ether, but not to saline. No CORT response to either stimulus was observed. In response to one exposure of each stimulus, deprived pups showed increased ACTH and CORT values and no further elevation to repeated exposure. These results suggest the negative feedback system of neonates is immature, but partially functional in deprived pups. Moreover, nondeprived pups show a stressor-specific response to stress, whereas deprived animals show a similar response to different stimuli.
这些研究调查了新生大鼠的激活和抑制（负反馈）情况。母体剥夺幼崽的促肾上腺皮质激素（ACTH）反应在30分钟内持续升高，这表明负反馈系统存在缺陷。在实验1中，我们研究了在发育过程中，120分钟内皮质酮（CORT）和ACTH对生理盐水注射的反应随时间的变化情况。在被剥夺的幼崽中，整个测试期间CORT和ACTH持续升高，而只有15日龄未被剥夺的幼崽出现ACTH和CORT升高。进一步地，将未被剥夺和被剥夺的幼崽间隔1小时两次暴露于乙醚（实验2）或生理盐水注射（实验3）。未被剥夺的幼崽对两次暴露于乙醚表现出增强的ACTH反应，但对生理盐水无此反应。未观察到对任何一种刺激的CORT反应。对于每种刺激的一次暴露，被剥夺的幼崽ACTH和CORT值增加，再次暴露时未进一步升高。这些结果表明，新生儿的负反馈系统不成熟，但在被剥夺的幼崽中部分功能正常。此外，未被剥夺的幼崽对压力表现出应激源特异性反应，而被剥夺的动物对不同刺激表现出类似反应。
