Department of Anatomy, School of Medicine, Konkuk University, 143-701 Seoul, Korea.
Brain Res. 2013 Jun 26;1519:40-52. doi: 10.1016/j.brainres.2013.04.039. Epub 2013 Apr 27.
The present study was designed to reveal cocaine- and amphetamine-regulated transcript (CART)- or neuropeptide Y (NPY)-immunoreactive neuronal projections from the hypothalamic arcuate nucleus (Arc) to the dorsal raphe (DR) and/or the locus coeruleus (LC) in the rat. Our results demonstrated that CART or NPY axon terminals formed close appositions to the neuronal profiles in the DR and the LC. Thus, arcuate sections were immunostained for the CART or NPY after the injections of green RetroBeads(™) into the DR and red tracer into the LC (or vice versa). First, retrogradely-labeled CART cells were mainly observed in the lateral Arc without colchicine. Of the total population of arcuate CART neurons, DR- and LC-projecting cells were 5.7% ± 0.9% and 6.6% ± 0.7%, respectively. In addition, a subset (3.3% ± 0.7%) of CART neurons provided divergent axon collaterals to the DR and the LC. Second, retrogradely-labeled NPY cells were observed in lateral or ventral borders of the medial Arc only after colchicine injection. Of the entire NPY cell population, DR- and LC-projecting neurons were 1.5% ± 0.3% and 1.3% ± 0.3%, respectively. Only a scanty proportion (0.1% ± 0.0%) sent axon collaterals to the DR and the LC. These observations suggested that arcuate CART or NPY system might have a potential influence on the brainstem monoaminergic nuclei, modulating their roles in feeding, nociception, emotional behaviors, arousal, and stress responses. Furthermore, a portion of arcuate CART neurons (along with only a few NPY cells) sending divergent axon collaterals to the DR/LC might have a simultaneous (and possibly more efficient) way to exert their specific influences on the monoaminergic nuclei.
本研究旨在揭示下丘脑弓状核（Arc）投射到背侧中缝核（DR）和/或蓝斑核（LC）的可卡因和安非他明调节的转录物（CART）或神经肽 Y（NPY）免疫反应性神经元投射。我们的结果表明，CART 或 NPY 轴突末端与 DR 和 LC 中的神经元形态形成紧密的贴合。因此，在将绿色 RetroBeads（™）注入 DR 和红色示踪剂注入 LC（或反之亦然）后，对 Arc 切片进行 CART 或 NPY 的免疫染色。首先，在没有秋水仙碱的情况下，主要在外侧 Arc 中观察到逆行标记的 CART 细胞。在整个 Arc 区 CART 神经元中，DR 和 LC 投射细胞分别为 5.7%±0.9%和 6.6%±0.7%。此外，CART 神经元的一个亚群（3.3%±0.7%）向 DR 和 LC 提供了发散的轴突侧支。其次，仅在注射秋水仙碱后，才在中脑 Arc 的外侧或腹侧边界观察到逆行标记的 NPY 细胞。在整个 NPY 细胞群体中，DR 和 LC 投射神经元分别为 1.5%±0.3%和 1.3%±0.3%。只有很少一部分（0.1%±0.0%）向 DR 和 LC 发出轴突侧支。这些观察结果表明，Arc 区 CART 或 NPY 系统可能对脑干单胺能核团具有潜在影响，调节其在摄食、痛觉、情绪行为、觉醒和应激反应中的作用。此外，一部分投射到 DR/LC 的 Arc 区 CART 神经元（以及极少数 NPY 细胞）发出发散的轴突侧支，可能有一种同时（可能更有效）的方式对单胺能核团发挥其特定影响。
