Gonadotropin-releasing hormone neurons coexpress orexin 1 receptor immunoreactivity and receive direct contacts by orexin fibers
Gonadotropin-releasing hormone neurons coexpress orexin 1 receptor immunoreactivity and receive direct contacts by orexin fibers
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DOI：
10.1210/en.2002-220958
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发表时间：
2003-04-01
期刊：
影响因子：
4.8
通讯作者：
Smith, MS
中科院分区：
文献类型：
--
作者：
Campbell, RE;Grove, KL;Smith, MS
食欲素产生于下丘脑外侧区的神经元中，并参与摄食和生殖功能的调节。食欲素刺激激素致敏卵巢切除雌性大鼠LH分泌，抑制非致敏卵巢切除大鼠LH分泌。本研究的目的是描述食欲素可能调节LH分泌的神经解剖学途径。使用双标记和三标记免疫荧光结合共聚焦显微镜，我们发现75-85%的GnRH神经元与食欲素纤维接触，突触素三标记提供了密切接触的额外确认。此外，约85%的GnRH神经元与食欲素受体1（OX-R1）共定位，OX-R1表达的GnRH神经元与食欲素终末接触，为功能性神经解剖学通路提供了基础。然而，正中隆起的GnRH神经末梢不表达OX-R1。另一项研究调查了与GnRH神经元相关的神经肽Y Y 4样受体和食欲素纤维的共表达。有证据表明，Y 4受体刺激导致LH释放，我们实验室的研究表明，在下丘脑外侧区的大多数食欲素细胞体和一些分散在下丘脑的食欲素纤维中存在Y 4样免疫反应性。本研究发现，虽然Y 4阳性的食欲素纤维存在于GnRH神经元的区域，但它们从不与GnRH神经元紧密接触。总之，这些数据表明，LH释放的Y 4受体调节可能是间接通过食欲素细胞体和食欲素调节GnRH神经元直接通过OX-R1。
The orexins are produced in neurons of the lateral hypothalamic area and implicated in the regulation of both feeding and reproductive function. Orexins stimulate LH secretion in steroid-primed ovariectomized female rats and suppress LH secretion in nonprimed ovariectomized rats. The aim of the present study was to characterize the neuroanatomical pathway by which orexin might modulate LH secretion in the rat. Using double- and triple-label immunofluorescence coupled with confocal microscopy, we found that 75-85% of GnRH neurons were contacted by orexin fibers, and triple labeling with synaptophysin provided additional confirmation of close contacts. Furthermore, about 85% of GnRH neurons were co-localized with the orexin receptor 1 (OX-R1), and the OX-R1-expressing GnRH neurons were contacted by orexin terminals, providing the basis for a functional neuroanatomical pathway. GnRH nerve terminals in the median eminence, however, do not express OX-R1. An additional study investigated the coexpression of neuropeptide Y Y4-like receptors and orexin fibers in relation to GnRH neurons. There is evidence that Y4 receptor stimulation results in LH release, and studies from our laboratory show Y4-like immunoreactivity in the majority of orexin cell bodies in the lateral hypothalamic area and some orexin fibers scattered throughout the hypothalamus. The present study found that, although Y4-positive orexin fibers are in present in the area of GnRH neurons, they never come in close contact with GnRH neurons. Together, these data suggest that Y4 receptor modulation of LH release is likely to be indirect through orexin cell bodies and that orexin modulates GnRH neurons directly via OX-R1.