急性低氧下中枢单胺水平变化及中枢 NE 与血浆皮质酮的关系

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	急性低氧下中枢单胺水平变化及中枢 NE 与血浆皮质酮的关系
	李江伟
学位类型	硕士
导师	杜继曾
	1997-06
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	中国科学院西北高原生物研究所
学位专业	动物学专业
关键词	低位脑干单胺皮质酮地塞米松肾上腺素受体鼠兔急性低氧
摘要	我们实验室曾证明急性低氧激活 HPA 轴，刺激下丘脑 CRF 释放，升高循环血中的 ACTH 水平和肾上腺皮质酮；并证明 Ach、5-HT 和 NE 可刺激离体培养的下丘脑神经元释放 CRF。然而，急性低氧下中枢 CA 能系统的变化及其对 HPA 轴作用尚未系统深入研究。本文通过模拟高原低氧和第三脑室注射 NE 及其阻断剂，系统研究了急性低氧下大鼠血浆皮质酮水平和低位脑干单胺类神经递质含量的变化，以及 AR 的参与机制，得出以下的结果：7km 急性低氧下大鼠血浆皮质酮水平显著性增加，下丘脑 NE 含量显著性降低。通过脑室注射α1 阻断剂 PZ 显著性抑制急性低氧下大鼠血浆皮质酮水平的升高，而脑室注射α2 阻断剂 YH 或β阻断剂 PP 均未对急性低氧下大鼠血浆皮质酮水平的升高产生显著性影响，并且联合使用 NE 受体阻断剂作用与单独使用α1 阻断剂 PZ 的作用类似。由此得出以下结论：在急性低氧下大鼠下丘脑 NE 含量与血浆皮质酮水平有相关性变化。包性低氧下脑干起源的 NE 通过α1 NE 受体激活 HPA 轴，导致大鼠血浆皮质酮水平的升高。并且这种作用在急性低氧中起主导性作用。腹腔注射 DM 后大鼠急性低氧中枢单胺递质的变化与大鼠直接低氧显示出极大的不同。DM 可能通过低位脑干丰富的糖皮质激素II型受体直接对单胺类神经元起作用，也可能是通过 PVN 区 CRF 能和／或 AVP 能神经元低位脑干单胺递质起作用。高原鼠兔仅在在 7km 低氧 2h 时血浆皮质酮水平显著性升高，由于高原鼠兔世代栖息在高海拔地区(3km-5km)，对高山低氧环境有特殊的适应能力。因此，高原鼠兔具有不同于大鼠的低氧应激适应机制。高原鼠兔脑内单胺含量对于急性低氧的反应与大鼠脑内单胺含量对于急性低氧的反应截然不同。急性低氧下高原鼠兔脑干单胺递质的显著性升高有何生理意义有待于进一步的研究。
其他摘要	We have studied the effects of hypoxia on the HPA axis and demonstrated that acute hypoxia activated HPA axis. The content of CRF in hypothalamus, ACTH and CORT in plasma would increase during acute hypoxia. We also founded that Ach, 5-HT and NE stimulated CRF secretion of PVN in vitro, however, the changes of catecholamine in brain stem and the effects of CA on the HPA axis in the rats exposed to hypoxia have not systematically investigated. In order to illuminate the relationship between the HPA axis and NE system in central. Using simulated altitude, we studied the changes of circulating CORT level and the contents of monoamines in brain stem and hypothalamus in Wistar rats during acute hypoxia. The results showed that: 1.the NE level in hypothalamus significantly decreased while the circulating CORT level significantly increased after 7km acute hypoxia, but they did not change after 5km acute hypoxia; 2.the level of plasma CORT in the rats received ice PZ/PZ+YH/PZ+YH+PP and followed hypoxia was significantly decreased while it in the rats received icv YH or PP and followed hypoxia did not change; 3. the concentration of monoamine in HT and BS in rats followed DM and is similar to it in Ochotona curzoniae followed acute hypoxia; 4. acute hypoxia did not change the plasma OCRT level of Pikas(O. curzoniae) and the changes of monoamines in the hypothalamus and brain stem also differed from the changes of the rats transferred to plateaus. It is suggested that acute hypoxia may activate catecholaminergic pathways, then facilitate the corticotropin-releasing factor(CRF) and/or AVP secretions from median eminence(ME), and reduce brain damage by the increased level of serum corticosterone in the rats exposed to hypoxia at last. The act of α1 adrenoceptors played a leading role in the regulation of HPA axis by NE originated from brain stem. There may be other pathways that can stimulate the HPA axis in hypoxia. It is concluded that DM may affect monoaminergic neurons through type 2 glucocorticoid receptors in brain stem or through CRF or/and AVP neurons in PVN. The native mammals, Ochotena curzoniae showed the best aptation, this is in accordance with our past work.
页数	38
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3350
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	李江伟. 急性低氧下中枢单胺水平变化及中枢 NE 与血浆皮质酮的关系[D]. 中国科学院西北高原生物研究所. 中国科学院西北高原生物研究所,1997.

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