Department of Biological Sciences, Center for Neuroscience Research, The RNA Institute, University At Albany, State University of New York, Albany, NY, USA.
Cell Mol Life Sci. 2021 Jun;78(12):5069-5082. doi: 10.1007/s00018-021-03829-3. Epub 2021 Apr 19.
The vomeronasal organ (VNO) is sensory organ located in the ventral region of the nasal cavity in rodents. The VNO develops from the olfactory placode during the secondary invagination of olfactory pit. The embryonic vomeronasal structure appears as a neurogenic area where migratory neuronal populations like endocrine gonadotropin-releasing hormone-1 (GnRH-1) neurons form. Even though embryonic vomeronasal structures are conserved across most vertebrate species, many species including humans do not have a functional VNO after birth. The vomeronasal epithelium (VNE) of rodents is composed of two major types of vomeronasal sensory neurons (VSNs): (1) VSNs distributed in the apical VNE regions that express vomeronasal type-1 receptors (V1Rs) and the G protein subunit Gαi2, and (2) VSNs in the basal territories of the VNE that express vomeronasal type-2 receptors (V2Rs) and the G subunit Gαo. Recent studies identified a third subclass of Gαi2 and Gαo VSNs that express the formyl peptide receptor family. VSNs expressing V1Rs or V2Rs send their axons to distinct regions of the accessory olfactory bulb (AOB). Together, VNO and AOB form the accessory olfactory system (AOS), an olfactory subsystem that coordinates the social and sexual behaviors of many vertebrate species. In this review, we summarize our current understanding of cellular and molecular mechanisms that underlie VNO development. We also discuss open questions for study, which we suggest will further enhance our understanding of VNO morphogenesis at embryonic and postnatal stages.
犁鼻器（VNO）是一种位于啮齿动物鼻腔腹侧区域的感觉器官。VNO 是由嗅基板在二次嗅凹陷入时发育而来的。胚胎犁鼻器结构表现为一个神经生成区，其中迁移神经元群体，如内分泌促性腺激素释放激素-1（GnRH-1）神经元形成。尽管胚胎犁鼻器结构在大多数脊椎动物物种中是保守的，但许多物种，包括人类，在出生后没有功能性的 VNO。啮齿动物的犁鼻上皮（VNE）由两种主要类型的犁鼻感觉神经元（VSN）组成：（1）分布在 VNE 顶端区域的 VSN，表达犁鼻型 1 受体（V1R）和 G 蛋白亚基 Gαi2；（2）VNE 基底区域的 VSN，表达犁鼻型 2 受体（V2R）和 G 亚基 Gαo。最近的研究确定了第三类 Gαi2 和 Gαo VSN，它们表达形式肽受体家族。表达 V1R 或 V2R 的 VSN 将其轴突发送到副嗅球（AOB）的不同区域。VNO 和 AOB 共同构成副嗅觉系统（AOS），这是一个嗅觉子系统，协调许多脊椎动物物种的社交和性行为。在这篇综述中，我们总结了我们对 VNO 发育的细胞和分子机制的现有理解。我们还讨论了有待研究的开放性问题，我们认为这些问题将进一步增强我们对胚胎和出生后阶段 VNO 形态发生的理解。
