Aliaga-Guerrero María, Paullada-Salmerón José A, Piquer Vanesa, Mañanós Evaristo L, Muñoz-Cueto José A
Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain.
INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain.
J Comp Neurol. 2018 Feb 1;526(2):349-370. doi: 10.1002/cne.24339. Epub 2017 Oct 30.
Recently, gonadotropin-inhibitory hormone (GnIH) has emerged as an important regulator of reproduction in birds and mammals. This RFamide neuropeptide has neuromodulatory functions and controls the synthesis and/or release of gonadotropin-releasing hormone (GnRH) and gonadotropins. Although teleosts represent about half of all living vertebrates, scientific and technological advances on the Gnih system in fish are scarce, contradictory, and inconclusive. Research on the fish Gnih system appears necessary to better clarify its role in the neuroendocrine and environmental control of vertebrate reproduction. In this study, we cloned a full-length sequence for the Gnih precursor of a flatfish, the Senegalese sole, coding for three putative Gnih peptides (ssGnih). We also generated specific antibodies against these ssGnih peptides, and used them to localize Gnih cells and their projections in the brain and pituitary. The expression of gnih was particularly evident in the diencephalon, but also in the olfactory bulbs/cerebral hemispheres, optic tectum/tegmentum, retina, and pituitary. The three antibodies used provided consistent results and showed that ssGnih-immunoreactive perikarya were present in the olfactory bulbs, ventral telencephalon, caudal preoptic area, dorsal tegmentum and rostral rhombencephalon, and their fibers innervated the brain and pituitary profusely. Intramuscular injection of ssGnih-3 provoked a significant reduction in gnrh-3 and lh expression, whereas ssGnih-2 treatment did not affect transcript levels of the main reproductive genes. Our results reveal the existence of a functional Gnih system in the sole brain, profusely innervating different brain areas and the pituitary gland, which could represent an important factor in the neuroendocrine control of flatfish reproduction.
最近，促性腺激素抑制激素（GnIH）已成为鸟类和哺乳动物生殖的重要调节因子。这种RF酰胺神经肽具有神经调节功能，可控制促性腺激素释放激素（GnRH）和促性腺激素的合成和/或释放。尽管硬骨鱼约占所有现存脊椎动物的一半，但关于鱼类GnIH系统的科技进展却很少，且相互矛盾、尚无定论。对鱼类GnIH系统进行研究似乎有必要，以便更好地阐明其在脊椎动物生殖的神经内分泌和环境控制中的作用。在本研究中，我们克隆了一种比目鱼——塞内加尔鳎的GnIH前体的全长序列，该序列编码三种假定的GnIH肽（ssGnIH）。我们还制备了针对这些ssGnIH肽的特异性抗体，并利用它们在大脑和垂体中定位GnIH细胞及其投射。gnih的表达在间脑中尤为明显，但在嗅球/大脑半球、视顶盖/被盖、视网膜和垂体中也有表达。所使用的三种抗体提供了一致的结果，表明ssGnIH免疫反应性核周体存在于嗅球、腹侧端脑、尾侧视前区、背侧被盖和吻侧菱脑，并且它们的纤维大量支配大脑和垂体。肌肉注射ssGnIH-3可显著降低gnrh-3和lh的表达，而ssGnIH-2处理不影响主要生殖基因的转录水平。我们的结果揭示了在鳎鱼大脑中存在一个功能性的GnIH系统，该系统大量支配不同的脑区和垂体，这可能是比目鱼生殖神经内分泌控制中的一个重要因素。
