Okamura Hiroaki, Yamamura Takashi, Wakabayashi Yoshihiro
Division of Animal Breeding and Reproduction Research, Institute of Livestock and Grassland Science, NARO, Ibaraki 305-0901, Japan.
J Reprod Dev. 2017 Dec 15;63(6):571-580. doi: 10.1262/jrd.2017-103. Epub 2017 Nov 7.
A population of neurons in the arcuate nucleus (ARC) coexpresses kisspeptin, neurokinin B (NKB), and dynorphin, and therefore they are referred to as KNDy neurons. It has been suggested that KNDy neurons participate in several brain functions, including the control of reproduction. The present study aimed to advance our understanding of the anatomy of the KNDy neural system. We first produced an antiserum against goat kisspeptin. After confirming its specificity, the antiserum was used to histochemically detect kisspeptin-positive signals. Using the colocalization of kisspeptin and NKB immunoreactivity as a marker for KNDy neurons, we mapped distributions of their cell somata and fibers in the whole brain (except the cerebellum) of ovariectomized (OVX) goats. KNDy neuronal somata were distributed throughout the ARC, and were particularly abundant in its caudal aspect. KNDy neuronal fibers projected into several areas within the septo-preoptic-hypothalamic continuum, such as the ARC, median eminence, medial preoptic nucleus, and bed nucleus of the stria terminalis. Kisspeptin immunoreactivity was not found outside of the continuum. We then addressed to the hypothesis that substance P (SP) is also involved in the KNDy neural system. Double-labeling immunohistochemistry for kisspeptin and SP revealed that KNDy neurons did not coexpress SP, but nearly all of the KNDy neuronal somata were surrounded by fibers containing SP in the OVX goats. The present results demonstrate anatomical evidence for a robust association between the KNDy and SP neural systems.
弓状核（ARC）中的一群神经元共同表达 kisspeptin、神经激肽 B（NKB）和强啡肽，因此它们被称为 KNDy 神经元。有人提出，KNDy 神经元参与多种脑功能，包括生殖控制。本研究旨在增进我们对 KNDy 神经系统解剖结构的理解。我们首先制备了一种针对山羊 kisspeptin 的抗血清。在确认其特异性后，该抗血清被用于组织化学检测 kisspeptin 阳性信号。以 kisspeptin 和 NKB 免疫反应性的共定位作为 KNDy 神经元的标志物，我们绘制了去卵巢（OVX）山羊全脑（小脑除外）中它们的细胞体和纤维的分布。KNDy 神经元细胞体分布于整个弓状核，在其尾部尤为丰富。KNDy 神经元纤维投射到隔区 - 视前区 - 下丘脑连续区域内的几个区域，如弓状核、正中隆起、内侧视前核和终纹床核。在该连续区域之外未发现 kisspeptin 免疫反应性。然后我们探讨了 P 物质（SP）也参与 KNDy 神经系统的假说。kisspeptin 和 SP 的双重免疫组织化学标记显示，KNDy 神经元不共表达 SP，但在 OVX 山羊中，几乎所有 KNDy 神经元细胞体都被含有 SP 的纤维所包围。本研究结果为 KNDy 和 SP 神经系统之间的紧密关联提供了解剖学证据。
