Stress‐induced Activation of Neurons in the Ventromedial Arcuate Nucleus: A Blood‐Brain‐CSF Interface of the Hypothalamus
Stress‐induced Activation of Neurons in the Ventromedial Arcuate Nucleus: A Blood‐Brain‐CSF Interface of the Hypothalamus
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应激诱导的腹内侧弓状核神经元激活：下丘脑的血脑脑脊液界面
DOI：
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发表时间：
2008
影响因子：
5.2
通讯作者：
M. Palkovits
中科院分区：
文献类型：
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作者：
M. Palkovits
在对疼痛相关的急性应激的反应中，研究了大鼠下丘脑中急性神经元兴奋的标志物c-fos蛋白（Fos）的表达。在下丘脑单次皮下注射4%福尔马林后15分钟，仅在室旁核（PVN）中观察到少数Fos免疫阳性细胞。15分钟后，大量的PVN小细胞神经元显示Fos表达。注射后60 min，弓状核出现强免疫反应，但Fos阳性神经元几乎只分布在核的腹内侧亚部。弓状核的这一部分的神经元主要表达神经肽Y（NPY），其投射到PVN的内侧小细胞亚群。先前的研究已经证明，弓状核的这一部分通过正中隆起的室管膜下丛接受部分来自垂体前叶的血液，并且它与正中隆起一起在内侧基底下丘脑中建立了一个无血脑屏障区。由于弓状神经元中的PVN投射NPY神经元对循环皮质酮水平的改变敏感，因此讨论了应激激活的下丘脑-垂体-肾上腺皮质系统中可能存在的短反馈途径。
In response to a pain‐related acute stress, the expression of c‐fos protein (Fos), a marker of acute neuronal excitation, was investigated in the hypothalamus of rats. Few Fos‐immunopositive cells were seen 15 min after a single subcutaneous injection of 4% formalin in the hypothalamus, but only in the paraventricular nucleus (PVN). Fifteen minutes later, a high number of parvocellular neurons of the PVN showed Fos expression. By 60 min after injection, strong immunoreactivity appeared in the arcuate nucleus, but the Fos‐positive neurons distributed almost exclusively in the ventromedial subdivision of the nucleus. Neurons in this part of the arcuate nucleus express mainly neuropeptide Y (NPY) that projects to the medial parvocellular subdivision of the PVN. It has been demonstrated by previous studies that this part of the arcuate nucleus receives blood partly from the anterior pituitary through the subependymal plexus of the median eminence, and that it establishes, together with the median eminence, a blood–brain barrier‐free area in the medial basal hypothalamus. Since the PVN‐projecting NPY neurons in the arcuate neurons are sensitive to alterations in circulating corticosterone levels, the existence of a possible short feedback route in the stress‐activated hypothalamo‐pituitary‐adrenocortical system is discussed.