Department of Epidemiology & Preventive Medicine and Anatomy & Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, USA.
Neuroscience. 2010 Oct 27;170(3):839-45. doi: 10.1016/j.neuroscience.2010.07.003. Epub 2010 Aug 3.
Galanin and neuropeptide Y (NPY) are among the most abundant neuropeptides in the hypothalamus. The role of NPY and galanin in the regulation of the secretory activity of the anterior pituitary has been well established. In addition, the two peptides interact with a number of neurons synthesizing the releasing and inhibiting hormones and a large number of other neuropeptides. The aim of the present studies was to explore if, as in rodents, NPY innervates galanin-immunoreactive (IR) neurons in the human diencephalon. Due to the long post mortem period and subsequent lack of optimal preservation of the cell membranes in the brain, electron microscopy could not be employed to show the presence of NPY-IR synapses on galanin-IR neurons. Therefore, we used light microscopic double label immunocytochemistry and high magnification microscopy with oil immersion to identify putative juxtapositions between NPY and galanin. Our studies show that similarly to rats, numerous NPY-IR nerve terminals surrounded galanin-IR neurons in the human hypothalamus. Among the hypothalamic regions, the infundibulum (infundibular or arcuate nucleus) contained the largest number of galanin-IR neurons heavily surrounded with NPY-IR nerve terminals. These en passant-type intimate associations between NPY-IR and galanin-IR neuronal elements may be functional synapses and may provide the morphological basis for the NPY-mediated galanin release. Consequently, NPY-galanin communication may mediate effects of NPY on neuronal systems innervated by galanin, and therefore may play a pivotal role in the regulation of reproduction, growth, energy and metabolism.
神经肽 Y（NPY）和神经肽 Y（Galanin）是下丘脑内含量最丰富的神经肽之一。NPY 和 Galanin 在调节垂体前叶的分泌活动中的作用已经得到很好的证实。此外，这两种肽与许多合成释放和抑制激素的神经元以及大量其他神经肽相互作用。本研究的目的是探索 NPY 是否像在啮齿动物中那样支配人类大脑下丘脑的 Galanin-IR 神经元。由于死后时间长，随后大脑细胞膜缺乏最佳保存，因此无法进行电子显微镜检查以显示 Galanin-IR 神经元上存在 NPY-IR 突触。因此，我们使用光学显微镜双重标记免疫细胞化学和高倍显微镜油浸来识别 NPY 和 Galanin 之间可能的并列。我们的研究表明，与大鼠类似，大量 NPY-IR 神经末梢围绕着人类下丘脑的 Galanin-IR 神经元。在下丘脑区域中，漏斗（漏斗或弓状核）包含数量最多的 Galanin-IR 神经元，这些神经元被 NPY-IR 神经末梢紧密包围。这些 NPY-IR 和 Galanin-IR 神经元之间的亲电子型紧密关联可能是功能性突触，并为 NPY 介导的 Galanin 释放提供形态学基础。因此，NPY-Galanin 通讯可能介导 NPY 对 Galanin 支配的神经元系统的影响，因此可能在调节生殖、生长、能量和代谢中发挥关键作用。
