Experimental evidence for an early commitment of gonadotropin-releasing hormone neurons, with special regard to their origin from the ectoderm of nasal cavity presumptive territory.
Experimental evidence for an early commitment of gonadotropin-releasing hormone neurons, with special regard to their origin from the ectoderm of nasal cavity presumptive territory.
复制标题
促性腺激素释放激素神经元早期定型的实验证据，特别是它们起源于鼻腔假定区域的外胚层。
DOI：
10.1159/000126490
复制
发表时间：
1993
影响因子：
4.1
通讯作者：
P. Dubois
中科院分区：
文献类型：
--
作者：
Aziz El Amraoui;P. Dubois
用间接免疫过氧化物酶法研究了正常和手术鸡胚促性腺激素释放激素（GnRH）神经元的起源和迁移。在正常胚胎中，在胚胎发育早期，GnRH神经元仅位于呼吸和嗅觉上皮。然后，这些神经元遵循最近的神经束，然后根据它们出现的时间和面积占据嗅神经的背侧、内侧或腹侧部分。在与前脑的交界处，大多数GnRH神经元通过腹内侧周围的嗅球。因此，它们穿过半球间空间，并斜向端脑尾部和背侧，随后将从那里分布到它们的成人样位置。鉴于这些神经元在鼻区的大量分布，从2至4体节阶段对整个或每个假定的鼻结构区域进行单侧手术消融。如预期的那样，当单侧切除嗅基板和鼻腔外胚层假定区域时，嗅神经、鼻结构和GnRH神经元在手术侧不能发育。单侧切除嗅板原基后，GnRH神经元的分布格局并没有受到干扰，以及在控制侧，虽然同侧的嗅觉结构大大减少。相反，当假定鼻腔外胚层单侧删除，GnRH神经元仅在对照侧，这一领域是完整的检测。因此，从神经发生的早期，GnRH神经元似乎已经定型，它们起源于鼻腔外胚层的假定领土。
The origin and the migration of gonadotropin-releasing hormone (GnRH)-producing neurons were studied using the indirect immunoperoxidase method in normal and surgically operated chick embryos. In normal embryos, during early embryonic development, GnRH neurons were located only in the respiratory and the olfactory epithelia. Then, these neurons followed the nearest nerve bundle and occupied, thereafter, the dorsal, medial or ventral part of the olfactory nerve according to the time and area of the olfactory epithelium they emerged from. At the junction with the forebrain, the majority of GnRH neurons passed ventromedially round the olfactory bulb. Therefore, they penetrated through the interhemispheric space and coursed obliquely toward caudal and dorsal telencephalon from where they will be later distributed to reach their adult-like position. In view of the large distribution of these neurons in the nasal region, unilateral surgical ablation either of the whole or of each presumptive territory of nasal structures was performed from 2 to 4 somite stages. As expected, when both olfactory placode and ectoderm of nasal cavity presumptive territories were unilaterally removed, olfactory nerve, nasal structures and GnRH neurons failed to develop in the operated side. After the unilateral removal of the olfactory placode anlage, the distribution pattern of GnRH neurons was not disturbed in the operated as well as in the control side although ipsilateral olfactory structures were greatly reduced. In contrast, when the presumptive ectoderm of nasal cavity was unilaterally removed, GnRH neurons were detected only in the control side where this territory was left intact. Therefore, from early neurogenesis, GnRH neurons seem to be already committed, and they originate from the ectoderm of nasal cavity presumptive territory.