Neurosecretory cells found along the dorsal strand of ascidians

沿海鞘背链发现的神经分泌细胞

• 批准号: 06804052
• 负责人: TERAKADO Kiyoshi
• 金额: $ 1.34万
• 依托单位: Saitama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06804052/
• 关键词: Protochordate; ascidian; neural complex; dorsal strand; GnRH neuron; pituitary hormone; hypophysis; immunocytochemistry; GTH陽性細胞; 下垂体; 神経分泌細胞; 免疫染色; 神経節; 神経分泌細胞群; 脳下垂体ホルモン様物質; 電子顕微鏡; モノクローナル抗体

Hypophysis, which functions to maintain the homeostasis in all vertebrate species, appears suddenly in its complete form in lower vertebrates. That is, the hypophysis is the organ unique for vertebrates and is absent in invertebrates. From a phylogenetic point of view, the possibility that any structure homologous to the vertebrate adenohypophysis may exist in protochordates has long been pointed out. In ascidians, the neural gland was considered to be homologous to the vertebrate adenohypophysis because of its morphological similarity. However, despite of recent extensive studies using various methods, the evidence that indicates its homology is very scarce.In this research project, we obtained some important cytochemical and developmental evidences revealing the homology of asacidian dorsal strand to the vertebrate adenohypophysis. They are : (1) presence of prolactin (PRL) -immunoreactive cells along the doesal strand. The localization of the immunoreactive material in the secretory granules of these cells has been ascertained by immunoelectron microscopy. (2) presence of gonadotropin (GTH) -immunoreactive cells. (3) presence of adrenocorticotropin (ACTH) -and POMC-related beta-endorphin immunoreactive cells. In adition, numerous gonadotropin-releasing hormone (GnRH) -producing neurons are localized in the vicinity of the dorsal strand. These structures in ascidians may correspond to the hypothalamus-pituitary system of vertebrate.

在所有脊椎动物物种中起维持体内平衡作用的垂体，在低等脊椎动物中突然以其完整的形式出现。也就是说，脑垂体是脊椎动物特有的器官，在无脊椎动物中不存在。从系统发生的观点来看，任何与脊椎动物腺垂体同源的结构都可能存在于原索动物中的可能性早已被指出。海鞘类的神经腺与脊椎动物的腺垂体在形态上相似，因此被认为是同源的。然而，尽管最近广泛的研究使用各种方法，证据表明，它的同源性是非常缺乏的，在本研究项目中，我们获得了一些重要的细胞化学和发育证据揭示asacidian背链的同源性脊椎动物腺垂体。它们是：（1）沿雌鼠股沿着存在催乳素（PRL）免疫反应细胞。这些细胞的分泌颗粒中的免疫反应物质的定位已被确定通过免疫电镜。(2)促性腺激素（GTH）免疫反应细胞的存在。(3)存在促肾上腺皮质激素（ACTH）和POMC相关β-内啡肽免疫反应细胞。此外，许多促性腺激素释放激素（GnRH）的神经元定位于附近的背股。海鞘的这些结构可能与脊椎动物的下丘脑-垂体系统相对应。

项目成果

Terakado K., Ogawa M., Inoue K., Yamamoto K., Kikuyama S.: "Prolactin-like immunoreactivity in the granules of neural complex cells in the ascidian Halocynthia roretzi" Cell Tissue Res.(in press). (1997)

Terakado K.、Okawa M.、Inoue K.、Yamamoto K.、Kikuyama S.：“海鞘类 Halocynthia roretzi 神经复合体细胞颗粒中的催乳素样免疫反应性”细胞组织研究（正在出版）。

Terakado K.et al.: "Prolactin-like immunoreactivity in the granules of neural complex cells in the ascidian Halocynthia roretzi" Cell and Tissue Research. (in press). (1997)

Terakado K.等人：“海鞘类 Halocynthia roretzi 神经复合体细胞颗粒中的催乳素样免疫反应性”细胞和组织研究。