NEUROPEPTIDE-Y INNERVATION OF BETA-ENDORPHIN-CONTAINING CELLS IN THE RAT MEDIOBASAL HYPOTHALAMUS - A LIGHT AND ELECTRON-MICROSCOPIC DOUBLE IMMUNOSTAINING ANALYSIS
NEUROPEPTIDE-Y INNERVATION OF BETA-ENDORPHIN-CONTAINING CELLS IN THE RAT MEDIOBASAL HYPOTHALAMUS - A LIGHT AND ELECTRON-MICROSCOPIC DOUBLE IMMUNOSTAINING ANALYSIS
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DOI：
10.1210/en.131.5.2461
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发表时间：
1992-11-01
期刊：
影响因子：
4.8
通讯作者：
LERANTH, C
中科院分区：
文献类型：
--
作者：
HORVATH, TL;NAFTOLIN, F;LERANTH, C
神经肽Y（NPY）的中枢给药抑制去卵巢大鼠垂体LH的释放，并刺激LH的释放在完整和去卵巢大鼠卵巢类固醇预处理。虽然确切的神经机制，这种双重作用的神经肽Y是未知的，实验证据表明，潜在的相互作用下丘脑神经肽Y和抑制β-内啡肽（β END）系统的神经内分泌调节垂体LH释放在大鼠。本研究旨在探讨下丘脑这两个肽能系统之间相互作用的形态学基础。秋水仙碱预处理的雌性大鼠的下丘脑内侧基底部的部分进行双重免疫染色的NPY和β END，并通过光学和电子显微镜检查。浅棕色的二氨基联苯胺反应被用来观察β END细胞，而NPY神经元则被深蓝色的硫酸镍铵-增强的二氨基联苯胺反应标记。在光镜下，观察到一个密集的网络，神经肽Y免疫反应阳性轴突和轴突终末在密切的并列与β END免疫反应阳性神经元在整个内侧基底下丘脑。电子显微镜检查显示，NPY免疫反应终扣形成轴体和轴树突触连接betaEND细胞。这些突触膜特化的大多数出现对称。根据以前的证据，兴奋和抑制作用LH释放和下丘脑中的NPY和LHRH神经元之间的直接突触连接的存在，目前的结果表明，NPY对LH分泌的双重作用可能涉及调制LHRH分泌，无论是通过直接途径和间接通过下丘脑β END系统。
Central administration of neuropeptide-Y (NPY) inhibits pituitary LH release in ovariectomized rats and stimulates LH release in intact and ovariectomized rats pretreated with ovarian steroids. Although the precise neural mechanism of this dual effect of NPY is not known, experimental evidence suggests an underlying interaction between hypothalamic NPY and the inhibitory beta-endorphin (betaEND) systems in the neuroendocrine regulation of pituitary LH release in the rat. The present study was undertaken to examine the morphological basis of the interaction between these two peptidergic systems in the hypothalamus. Sections of the mediobasal hypothalamus of colchicine-pretreated female rats were double immunostained for NPY and betaEND and examined by light and electron microscopy. The light brown diaminobenzidine reaction was used to visualize betaEND cells, while NPY neurons were labeled with a dark blue nickel ammonium sulfate-intensified diaminobenzidine reaction. Under the light microscope, a dense network of NPY-immunoreactive axons and axon terminals was observed in close apposition with betaEND-immunoreactive neurons throughout the medial basal hypothalamus. Electron microscopic examination revealed that NPY-immunoreactive boutons formed axosomatic and axo-dendritic synaptic connections with betaEND cells. A majority of these synaptic membrane specializations appeared symmetrical. In light of the previous evidence of excitatory and inhibitory effects on LH release and the existence of direct synaptic connections between NPY and LHRH neurons in the hypothalamus, the current results imply that the dual effects of NPY on LH secretion may involve modulation of LHRH secretion, both by the direct route and indirectly through the hypothalamic betaEND system.