Malarkey W B, Lipkus I M, Cacioppo J T
Department of Internal Medicine, Ohio State University, Columbus 43210, USA.
J Clin Endocrinol Metab. 1995 Aug;80(8):2458-63. doi: 10.1210/jcem.80.8.7629242.
The hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) systems are implicated in the human stress response. One characterization of these systems is that they are nonspecific in their response, but differ in activation threshold and time course. Additionally, they have been found to be affected commonly by strong metabolic stressors and infusions of CRH, and a hypothesis has been developed primarily from animal research that CRH stimulates both the HPA and SAM systems. To determine whether CRH was significantly involved in tonic as well as psychological stress-induced catecholamine levels in man, we infused 24 normal male undergraduate students with either saline (n = 12) or dexamethasone (DEX; n = 12) and evaluated their subsequent plasma levels of ACTH, cortisol, epinephrine (EPI), and not epinephrine (NEPI). DEX produced a dramatic decrease in ACTH and cortisol levels, but no significant changes in EPI or NEPI occurred over a 4-h sampling interval. After the administration of math and speech stressors in a controlled laboratory setting, DEX inhibited the ACTH and cortisol release that was noted in the saline group, but stress-induced increases in EPI and NEPI were comparable in both groups. Thus, our study suggests that there is a difference in the neural pathways for tonic and stress-induced stimulation of the SAM and HPA systems.
下丘脑-垂体-肾上腺（HPA）系统和交感-肾上腺髓质（SAM）系统参与人类应激反应。这些系统的一个特点是它们的反应是非特异性的，但激活阈值和时间进程有所不同。此外，已发现它们通常受强烈代谢应激源和促肾上腺皮质激素释放激素（CRH）输注的影响，并且主要基于动物研究提出了一个假说，即CRH刺激HPA和SAM系统。为了确定CRH是否显著参与人类静息及心理应激诱导的儿茶酚胺水平，我们给24名正常男性本科学生输注生理盐水（n = 12）或地塞米松（DEX；n = 12），并评估他们随后血浆中促肾上腺皮质激素（ACTH）、皮质醇、肾上腺素（EPI）和去甲肾上腺素（NEPI）的水平。DEX使ACTH和皮质醇水平显著降低，但在4小时的采样间隔内，EPI或NEPI没有显著变化。在受控实验室环境中施加数学和言语应激源后，DEX抑制了生理盐水组中观察到的ACTH和皮质醇释放，但两组中应激诱导的EPI和NEPI增加相当。因此，我们的研究表明，SAM和HPA系统的静息及应激诱导刺激的神经通路存在差异。
