Song Y, Duan X, Chen J, Huang W, Zhu Z, Hu W
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
J Neuroendocrinol. 2015 Mar;27(3):198-211. doi: 10.1111/jne.12251.
Kisspeptin is a neuroendocrine hormone with a critical role in the activation of gonadotrophin-releasing hormone (GnRH) neurones, which is vital for the onset of puberty in mammals. However, the functions of kisspeptin neurones in non-mammalian vertebrates are not well understood. We have used transgenics to labell kisspeptin neurones (Kiss1 and Kiss2) with mCherry in zebrafish (Danio rerio). In kiss1:mCherry transgenic zebrafish, Kiss1 cells were located in the dorsomedial and ventromedial habenula, with their nerve fibres contributing to the fasciculus retroflexus and projecting to the ventral parts of the interpeduncular and raphe nuclei. In kiss2:mCherry zebrafish, Kiss2 cells were primarily located in the dorsal zone of the periventricular hypothalamus and, to a lesser extent, in the periventricular nucleus of the posterior tuberculum and the preoptic area. Kiss2 fibres formed a wide network projecting into the telencephalon, the mesencephalon, the hypothalamus and the pituitary. To study the relationship of kisspeptin neurones and GnRH3 neurones, these fish were crossed with gnrh3:EGFP zebrafish to obtain kiss1:mCherry/gnrh3:EGFP and kiss2:mCherry/gnrh3:EGFP double transgenic zebrafish. The GnRH3 fibres ascending to the habenula were closely associated with Kiss1 fibres projecting from the ventral habenula. On the other hand, GnRH3 fibres and Kiss2 fibres were adjacent but scarcely in contact with each other in the telencephalon and the hypothalamus. The Kiss2 and GnRH3 fibres in the ventral hypothalamus projected into the pituitary via the pituitary stalk. In the pituitary, Kiss2 fibres were directly in contact with GnRH3 fibres in the pars distalis. These results reveal the pattern of kisspeptin neurones and their connections with GnRH3 neurones in the brain, suggesting distinct mechanisms for Kiss1 and Kiss2 in regulating reproductive events in zebrafish.
亲吻素是一种神经内分泌激素，在促性腺激素释放激素（GnRH）神经元的激活中起关键作用，这对哺乳动物青春期的开始至关重要。然而，亲吻素神经元在非哺乳动物脊椎动物中的功能尚未得到充分了解。我们利用转基因技术，在斑马鱼（Danio rerio）中用mCherry标记亲吻素神经元（Kiss1和Kiss2）。在kiss1:mCherry转基因斑马鱼中，Kiss1细胞位于背内侧和腹内侧缰核，其神经纤维汇入缰核脚间束，并投射到脚间核和中缝核的腹侧部分。在kiss2:mCherry斑马鱼中，Kiss2细胞主要位于室周下丘脑的背侧区，在较小程度上位于后结节室周核和视前区。Kiss2纤维形成一个广泛的网络，投射到端脑、中脑、下丘脑和垂体。为了研究亲吻素神经元与GnRH3神经元的关系，将这些鱼与gnrh3:EGFP斑马鱼杂交，以获得kiss1:mCherry/gnrh3:EGFP和kiss2:mCherry/gnrh3:EGFP双转基因斑马鱼。上升至缰核的GnRH3纤维与从腹侧缰核投射的Kiss1纤维紧密相连。另一方面，在端脑和下丘脑中，GnRH3纤维和Kiss2纤维相邻，但几乎不相互接触。下丘脑腹侧的Kiss2和GnRH3纤维通过垂体柄投射到垂体。在垂体中，Kiss2纤维与远侧部的GnRH3纤维直接接触。这些结果揭示了亲吻素神经元在脑中的分布模式及其与GnRH3神经元的连接，表明Kiss1和Kiss2在调节斑马鱼生殖活动中具有不同的机制。
