Effects of orexins on the hypothalamic-pituitary-adrenal system
Effects of orexins on the hypothalamic-pituitary-adrenal system
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DOI：
10.1046/j.1365-2826.2000.00572.x
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发表时间：
2000-12-01
影响因子：
3.2
通讯作者：
Telegdy, G
中科院分区：
文献类型：
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作者：
Jászberényi, M;Bujdosó, E;Telegdy, G
本文研究了新发现的神经肽orexin-A和orexin-B对下丘脑-垂体-肾上腺（HPA）系统的影响。一个体内系统被用来评估食欲素- a和食欲素- b的中心作用。将不同剂量（2.8 ~ 560pmol）的增重素注入成年雄性大鼠脑室，并以血浆皮质酮作为HPA系统激活程度的指标。两种多肽均表现出明显的剂量反应作用，尽管增食欲素- b被证明不如增食欲素- a有效。促肾上腺皮质激素释放激素（CRH）拮抗剂α -螺旋CRH9-41预处理完全阻止食欲素的作用。进一步腹腔注射促肾上腺皮质激素（ACTH）、促肾上腺皮质激素a、促肾上腺皮质激素b。虽然ACTH引起显著的肾上腺反应，但增食欲素不影响基础分泌。肾上腺切片经克雷布斯溶液充氧和灌注后，也用促食欲素a、促食欲素b或促肾上腺皮质激素处理。两种增食欲素都不能改变皮质酮的释放，但ACTH诱导了明显的肾上腺反应。这项研究表明，这些食欲调节肽可能在中枢水平激活HPA系统，但食欲素- a和食欲素- b似乎都没有直接调节肾上腺皮质酮的释放。
The effects of the recently identified neuropeptides orexin-A and orexin-B on the hypothalamic-pituitary-adrenal (HPA) system were investigated. An in vivo system was used to assess the central effects of both orexin-A and orexin-B. Different doses of the orexins (2.8-560 pmol) were administered intracerebroventricularly (i.c.v.) to adult male rats, and plasma corticosterone was used as an index of the degree of the activation of the HPA system. Both peptides exhibited a clear dose-response action, although orexin-B proved to be less effective than orexin-A. Pretreatment with the corticotropin-releasing hormone (CRH) antagonist alpha -helical CRH9-41 completely prevented the action of the orexins. Orexin-A, orexin-B or adrenocorticotropic hormone (ACTH) was further administered intraperitoneally (i.p.). While ACTH evoked a significant adrenal response, the orexins did not influence the basal secretion. Adrenal slices, oxygenized and perifused with Krebs' solution, were also treated with orexin-A, orexin-B or ACTH. Both orexins failed to modify the release of corticosterone, but ACTH induced a marked adrenal response. This study suggests that these appetite-regulating peptides might activate the HPA system at a central level but neither orexin-A nor orexin-B appears to modulate directly the adrenal corticosterone release.