Hu Pu, Liu Ji, Yasrebi Ali, Gotthardt Juliet D, Bello Nicholas T, Pang Zhiping P, Roepke Troy A
Department of Animal Sciences (P.H., A.Y., J.D.G., N.T.B., T.A.R.), School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, and Child Health Institute of New Jersey (J.L., Z.P.P.) and Department of Neuroscience and Cell Biology (J.L., Z.P.P.), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901.
Endocrinology. 2016 Sep;157(9):3604-20. doi: 10.1210/en.2016-1191. Epub 2016 Jul 7.
CRH neurons in the hypothalamic paraventricular nucleus (PVN) play a central role in regulating the hypothalamus-pituitary-adrenal (HPA) axis and are directly influenced by 17β-estradiol (E2). Although compelling evidence has suggested the existence of membrane-associated estrogen receptors (mERs) in hypothalamic and other central nervous system neurons, it remains unknown whether E2 impacts CRH neuronal excitability through this mechanism. The purpose of the current study is to examine the existence and function of mER signaling in PVN CRH neurons. Whole-cell recordings were made from CRH neurons identified by Alexa Fluor 594 labeling and post hoc immunostaining in ovariectomized female mice. E2 (100nM) rapidly suppressed the M-current (a voltage-dependent K(+) current) and potentiated glutamatergic excitatory postsynaptic currents. The putative Gq-coupled mER (Gq-mER) characterized in hypothalamic proopiomelanocortin neurons initiates a phospholipase C-protein kinase C-protein kinase A pathway; therefore, we examined the involvement of this pathway using selective inhibitors. Indeed, the ER antagonist ICI 182780 and inhibitors of Gq-phospholipase C-protein kinase C-protein kinase A blocked E2's actions, suggesting dependence on the Gq-mER. Furthermore, STX, a selective ligand for the Gq-mER, mimicked E2's actions. Finally, to examine the in vivo effect of Gq-mER activation, E2 or STX injection increased c-fos expression in CRH neurons in the PVN, suggesting CRH neuronal activation. This corresponded to an increase in plasma corticosterone. We conclude that the Gq-mER plays a critical role in the rapid regulation of CRH neuronal activity and the HPA axis. Our findings provide a potential underlying mechanism for E2's involvement in the pathophysiology of HPA-associated mood disorders.
下丘脑室旁核（PVN）中的促肾上腺皮质激素释放激素（CRH）神经元在调节下丘脑 - 垂体 - 肾上腺（HPA）轴中起核心作用，并直接受17β - 雌二醇（E2）影响。尽管有确凿证据表明下丘脑和其他中枢神经系统神经元中存在膜相关雌激素受体（mERs），但E2是否通过该机制影响CRH神经元兴奋性仍不清楚。本研究的目的是检测PVN中CRH神经元mER信号的存在及功能。在去卵巢雌性小鼠中，通过Alexa Fluor 594标记和事后免疫染色鉴定CRH神经元，进行全细胞记录。E2（100nM）迅速抑制M电流（一种电压依赖性钾电流）并增强谷氨酸能兴奋性突触后电流。在下丘脑促阿片黑素皮质素神经元中表征的假定Gq偶联mER（Gq - mER）启动磷脂酶C - 蛋白激酶C - 蛋白激酶A途径；因此，我们使用选择性抑制剂检测该途径的参与情况。事实上，雌激素拮抗剂ICI 182780和Gq - 磷脂酶C - 蛋白激酶C - 蛋白激酶A抑制剂阻断了E2的作用，表明依赖于Gq - mER。此外，Gq - mER的选择性配体STX模拟了E2的作用。最后，为检测Gq - mER激活的体内效应，注射E2或STX增加了PVN中CRH神经元的c - fos表达，表明CRH神经元被激活。这与血浆皮质酮增加相对应。我们得出结论，Gq - mER在CRH神经元活动和HPA轴的快速调节中起关键作用。我们的研究结果为E2参与HPA相关情绪障碍的病理生理学提供了潜在的基础机制。
