Neuroanatomical basis for facilitation of hypothalamic-pituitary-adrenal responses to a novel stressor after chronic stress
Neuroanatomical basis for facilitation of hypothalamic-pituitary-adrenal responses to a novel stressor after chronic stress
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DOI：
10.1016/s0306-4522(97)00577-0
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发表时间：
1998-06-01
期刊：
影响因子：
3.3
通讯作者：
Dallman, M
中科院分区：
文献类型：
--
作者：
Bhatnagar, S;Dallman, M
暴露于慢性应激的动物对新的急性刺激表现出正常或增强的下丘脑-垂体-肾上腺反应，尽管内源性皮质类固醇对慢性应激源的反应是抑制性的。先前的压力被认为是诱导中枢促进痕迹，在暴露于新的刺激时，平衡或克服皮质酮的抑制作用。这种促进下丘脑-垂体-肾上腺反应的神经解剖学基础尚不清楚。在这项研究中，我们首先发现，暴露于间歇性寒冷环境7天的大鼠，肾上腺皮质激素和皮质酮对新的约束应激源的反应增加。然后，我们比较了对照组和慢性应激大鼠在限制30分钟后不同时间26个部位的fos免疫反应细胞数量。60 min时，慢性应激大鼠臂旁/Kolliker-Fuse区、后室旁丘脑、杏仁核中央核、基底外侧核和基底内侧核以及室旁下丘脑旁细胞核的fos染色细胞密度显著高于对照组。丘脑的后室旁核接受臂旁核的投射，并大量投射到杏仁核的差异染色亚核，杏仁核又投射到下丘脑的室旁旁细胞核。我们提出，在慢性应激大鼠中，臂旁-后室旁丘脑-扁桃体-旁细胞室旁下丘脑的活动增加是下丘脑-垂体-肾上腺轴对新应激的促进的基础。我们通过证明丘脑室旁后核的损伤只在先前长期应激的动物中增加促肾上腺皮质激素对约束的反应，证实了这一建议的部分内容。这种电位回路为进一步研究这些区域在应激诱导的下丘脑-垂体-肾上腺活性促进中的功能作用提供了基础。(c) 1998 ibro。Elsevier Science Ltd.出版。
Animals exposed to chronic stress exhibit normal or enhanced hypothalamic-pituitary-adrenal responses to novel, acute stimuli despite the inhibitory endogenous corticosteroid response to the chronic stressor. Prior stress is thought to induce a central facilitatory trace that, upon exposure to a novel stimulus, balances or overcomes the inhibitory effects of corticosterone. The neuroanatomical basis for this facilitation of hypothalamic-pituitary-adrenal responses is unknown. In this study, we first show increased adrenocorticotropin and corticosterone responses to the novel stressor of restraint in rats exposed to intermittent cold for seven days. We then compared numbers of Fos-immunoreactive cells in 26 sites in control and chronically stressed rats at various times after onset of a 30 min restraint. At 60 min, density of Fos-stained cells was significantly higher in chronically stressed than in control rats in the parabrachial/Kolliker-Fuse area, posterior paraventricular thalamus, central, basolateral and basomedial nuclei of the amygdala and parvocellular paraventricular hypothalamus. The posterior paraventricular nucleus of the thalamus receives projections from the parabrachial nucleus and projects heavily to the differentially stained subnuclei of the amygdala, which in turn project to the parvocellular paraventricular nucleus of the hypothalamus.We propose that increased activity in the parabrachial-posterior paraventricular thalamus-amypdala-parvocellular paraventricular hypo thalamus underlies facilitation of the hypothalamic-pituitary-adrenal axis to novel stress in chronically stressed rats. We confirmed part of this proposal by showing that lesions of the posterior paraventricular nucleus of the thalamus increase adrenocorticotropin responses to restraint only in previously chronically stressed animals. This potential circuit provides a basis for further examination of the functional roles of these regions in stress-induced facilitation of hypothalamic-pituitary-adrenal activity. (C) 1998 IBRO. Published by Elsevier Science Ltd.