Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina.
Gen Comp Endocrinol. 2022 Feb 1;317:113974. doi: 10.1016/j.ygcen.2021.113974. Epub 2021 Dec 30.
Kisspeptin (KISS), a key hormone involved in the regulation of the hypothalamic-pituitary-ovarian (HPO) axis, has been localized in the anteroventral periventricular (AVPV) nucleus and the neighboring rostral periventricular nucleus (PeVN), and in the arcuate (ARC) nucleus of the mammalian hypothalamus. In the ARC, the KISS neurons that co-express neurokinin B (NKB) and dynorphin A (Dyn) are named KNDy cells. The South American plains vizcacha is a rodent with peculiar reproductive traits. Around mid-pregnancy, vizcacha shows the reactivation of its HPO axis with the pulsatile release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH), an essential event for the success of gestation. Considering the role of KISS system in GnRH modulation, the aim of this work was to study their neuroanatomical distribution in adult vizcachas. AVPV showed sexual dimorphism with a significant smaller area in males (t-Test, p < 0.05), and KISS immunoreactivity was detected in somas and varicosities homogenously distributed in the AVPV with a concordant sex-related expression pattern. NKB and Dyn expression was also observed in cytoplasm of neurons scattered in the AVPV. Three subpopulations of neurons were detected in the AVPV: neurons expressing Dyn and NKB (DyNK cells), neurons expressing KISS and NKB (KiNK cells), and single NKB expressing neurons. Strikingly, KISS and Dyn were always expressed in different cells. In addition, in the ARC nucleus, KNDy cells were detected. On the other hand, KISS and GnRH expression was detected in different subpopulations of neurons, GnRH cells showed KISS receptor (KISSR or GPR-54) expression, and KISS immunoreactive afferent contacts were detected making close appositions onto somas and dendrites of GnRH cells. These results show similarities and differences between the KISS system in the hypothalamus of the vizcacha and other mammals, and constitute crucial observations about KISS and GnRH relation. Considering the peculiarity of HPO axis regulation in this species, the present work provides a neuroanatomical framework for the further elucidation of molecular mechanisms underlying GnRH expression and secretion.
Kisspeptin (KISS)，一种参与调节下丘脑-垂体-卵巢 (HPO) 轴的关键激素，已在哺乳动物下丘脑的前腹侧室旁核 (AVPV) 和相邻的前室旁核 (PeVN) 以及弓状核 (ARC) 中被定位。在 ARC 中，共同表达神经激肽 B (NKB) 和强啡肽 A (Dyn) 的 KISS 神经元被称为 KNDy 细胞。南美平原 vizcacha 是一种具有特殊生殖特征的啮齿动物。大约在妊娠中期，vizcacha 显示其 HPO 轴重新激活，伴随着促性腺激素释放激素 (GnRH) 和黄体生成素 (LH) 的脉冲释放，这是妊娠成功的重要事件。考虑到 KISS 系统在 GnRH 调节中的作用，本工作旨在研究其在成年 vizcachas 中的神经解剖分布。AVPV 显示出性别二态性，雄性的面积明显较小 (t 检验，p<0.05)，并且在 AVPV 中均匀分布的 somas 和 varicosities 中检测到 KISS 免疫反应性，表现出一致的性别相关表达模式。NKB 和 Dyn 的表达也在 AVPV 中的神经元细胞质中观察到。在 AVPV 中检测到三种神经元亚群：表达 Dyn 和 NKB 的神经元 (DyNK 细胞)、表达 KISS 和 NKB 的神经元 (KiNK 细胞) 和仅表达 NKB 的神经元。值得注意的是，KISS 和 Dyn 总是在不同的细胞中表达。此外，在 ARC 核中，检测到 KNDy 细胞。另一方面，在不同的神经元亚群中检测到 KISS 和 GnRH 的表达，GnRH 细胞显示出 KISS 受体 (KISSR 或 GPR-54) 的表达，并且 KISS 免疫反应性传入接触被检测到与 GnRH 细胞的 somas 和树突形成紧密的贴合。这些结果显示了 vizcacha 下丘脑内 KISS 系统与其他哺乳动物之间的相似性和差异，并构成了关于 KISS 和 GnRH 关系的关键观察结果。考虑到该物种 HPO 轴调节的特殊性，本工作为进一步阐明 GnRH 表达和分泌的分子机制提供了神经解剖学框架。
