Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
J Comp Neurol. 2010 May 1;518(9):1556-69. doi: 10.1002/cne.22290.
Neuroglobin (Ngb) is a myoglobin-like (Mb) heme-globin, belonging the globin family located only in neuronal tissue of the central nervous system. Ngb has been shown to be upregulated in and to protect neurons from hypoxic and ischemic injury, but the function of Ngb-in particular how Ngb may protect neurons-remains largely elusive. We have previously described the localization of Ngb in the rat brain and found it to be expressed in areas primarily involved in sleep/wake, circadian, and food regulation. The present study was undertaken, using immunohistochemistry, to characterize the localization, colocalization, innervation, and response to light of Ngb-immunoreactive (IR) cells in the rat suprachiasmatic nucleus (SCN). Our results demonstrate that the majority of Ngb-expressing neurons in the SCN belong to a cell group not previously characterized by neurotransmitter content; only a small portion was found to co-store GRP in the ventral SCN. Furthermore, some Ngb-containing neurons were responsive to light stimulation at late night evaluated by the induction of cFOS and only a few cells were found to express the core clock gene PER1 during the 24-hour light/dark cycle. The Ngb-containing cells received input from neuropeptide Y (NPY)-containing nerve fibers of the geniticulo-hypothalamic tract (GHT), whereas no direct input from the eye or the midbrain raphe system was demonstrated. The results indicate that the Ngb could be involved in both photic and nonphotic entrainment via input from the GHT.
神经球蛋白（Ngb）是一种肌红蛋白样（Mb）血红素蛋白，属于球蛋白家族，仅存在于中枢神经系统的神经元组织中。研究表明，Ngb 在缺氧和缺血损伤中上调，并保护神经元，但 Ngb 的功能——尤其是 Ngb 如何保护神经元——仍然很大程度上难以捉摸。我们之前描述了 Ngb 在大鼠脑中的定位，并发现它在主要参与睡眠/觉醒、昼夜节律和食物调节的区域表达。本研究采用免疫组织化学方法，研究 Ngb 免疫反应（IR）细胞在大鼠视交叉上核（SCN）中的定位、共定位、神经支配和对光的反应。我们的结果表明，SCN 中表达 Ngb 的大多数神经元属于一个以前没有根据神经递质含量来描述的细胞群；仅在 SCN 腹侧发现一小部分细胞共储存 GRP。此外，一些含有 Ngb 的神经元对深夜的光刺激有反应，通过诱导 cFOS 来评估，并且在 24 小时光/暗周期中仅发现少数细胞表达核心时钟基因 PER1。含有 Ngb 的细胞接收来自下丘脑生殖核神经纤维（GHT）的神经肽 Y（NPY）含量的神经纤维的输入，而没有证明来自眼睛或中脑中缝系统的直接输入。结果表明，Ngb 可以通过来自 GHT 的输入参与光和非光节律的同步。
