Effect of a chronic stress on CRF neuronal activity and expression of its type 1 receptor in the rat brain
Effect of a chronic stress on CRF neuronal activity and expression of its type 1 receptor in the rat brain
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DOI：
10.1152/ajpregu.1998.275.5.r1438
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发表时间：
1998-11-01
影响因子：
2.8
通讯作者：
Rivest, S
中科院分区：
文献类型：
--
作者：
Bonaz, B;Rivest, S
本研究的目的是比较急性与慢性束缚应激对大鼠下丘脑室旁核（PVN）c-fos和促肾上腺皮质激素释放因子1型受体（CRF 1受体）基因表达的影响。雄性Sprague-Dawley大鼠暴露于单次90分钟的固定应激或连续11天的相同会话。动物被深度麻醉之前（对照）;立即，1.5，3，6，或12小时后，急性应激;或后的最后一届会议的反复暴露固定。切下脑冠状冷冻切片（30 μ m），用S-35标记的核糖核酸探针通过原位杂交组织化学法测定编码大鼠c-ibs和CRF 1受体的mRNA。这些成绩单内PVN CRF免疫反应（IR）神经元的本地化也被确定。编码c-fos或CRF 1受体的mRNA的表达在对照动物的PVN中几乎检测不到，但急性应激会话在该内分泌核中诱导了两种转录物的强信号。许多CRF-IR神经元在急性应激动物的PVN中编码c-fos或CRF 1受体的基因呈阳性。相比之下，慢性应激动物的PVN在最后一次应激后显示出显著较低的CRF 1受体mRNA信号。在这些动物中，应力诱导的转录c-fos mRNA发生在大细胞PVN 90分钟后结束的最后一个应力会议，但只有一个低信号被检测到在小细胞分裂。此外，很少有CRF-IR神经元的PVN表达CRF 1受体或c-fos转录在慢性应激大鼠。这些数据提供了证据的适应性细胞机制，涉及一个衰减的行动，CRF的PVN在重复的同型应激暴露。
The purpose of this study was to compare the effect of an acute versus a chronic immobilization stress on the genetic expression of c-fos and corticotropin-releasing factor type 1 receptor (CRF1 receptor) in the paraventricular nucleus (PVN) of the rat hypothalamus. Male Sprague-Dawley rats were exposed to either a single 90-min immobilization stress or the same session for 11 consecutive days. Animals were deeply anesthetized before (control); immediately, 1.5, 3, 6, or 12 h after the acute stress; or after the last session of the repeated exposures to immobilization. Coronal frozen sections (30 mu m) of the brains were cut and mRNAs encoding the rat c-ibs and CRF1 receptor were assayed by in situ hybridization histochemistry using S-35-labeled riboprobes. Localization of these transcripts within PVN CRF-immunoreactive (ir) neurons was also determined. The expression of the mRNA encoding either c-fos or CRF1 receptor was barely detectable to low in the PVN of control animals, but the acute stress session induced a robust signal for both transcripts in this endocrine nucleus. Numerous CRF-ir neurons were positive for the gene encoding either c-fos or CRF1 receptor in the PVN of acutely stressed animals. In contrast, the PVN of chronically stressed animals displayed a significantly lower CRF1 receptor mRNA signal after the last stress session. In these animals, stress-induced transcription of c-fos mRNA occurred in the magnocellular PVN 90 min after the end of the last stress session but only a low signal was detected in the parvocellular division. Moreover, very few CRF-ir neurons of the PVN expressed either the CRF1 receptor or c-fos transcript in chronically stressed rats. These data provide evidence for an adaptive cellular mechanism involving an attenuated action of CRF within the PVN in response to repeated homotypic stress exposures.