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MIGRATION OF THE LHRH NEURONS FROM THE NASAL REGION TO THE FOREBRAIN.

LHRH 神经元从鼻区迁移到前脑。

基本信息

批准号：
16500227
负责人：
MURAKAMI Shizuko
金额：
$ 0.77万
依托单位：
JUNTENDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

In the chick embryo, LHRH neurons originate in the olfactory placode and migrate to the forebrain during embryonic days(E) 3.5-11. Examination of the normal development of LHRH neurons indicates that two major pathways of LHRH neuron migration exist in the brain. The main pathway of LHRH neuron migration largely corresponds to the course of the olfactory related fibers. At the most caudal level of this pathway, where the septal area develops, many LHRH neurons turn ventrally in direction of the ventral preoptic area. These LHRH neurons deviate from the olfactory related fibers. The dispersion of LHRH neurons from the nerve fibers implicates that another guidance cues contribute to the migration of LHRH neurons towards the preoptic area. From these findings, it is proposed that a character of LHRH neurons in the preoptic area differs from that in the septal area.To examine whether the birthdate of LHRH neurons influences their final locations, a single dose of BrdU was injected into eggs at different stages. LHRH neurons born at E2.5-4.5 were found in the entire final distribution areas at E11.5 and E18.5. In contrast, LHRH neurons born at E5.5-6.5 were not observed in the ventral preoptic region. It might be possible that late-generated LHRH neurons could not move in direction to the preoptic area. Structural and chemical guidance substrates for LHRH neuron migration might be lost at that time when late-generated LHRH neurons migrate toward the preoptic area.Netrin-1 is a diffusible molecule that guides various axons and cells migration. Netrin-1 mRNA was strongly expressed in the ventral hypothalamus but not in the dorsomedial forebrain at E7.5. Netrin-1 may be a candidate molecule for LHRH neuron migration from the dorsal preseptal area to the ventral preoptic area.

在鸡胚胎中，LHRH 神经元起源于嗅觉基板，并在胚胎期 (E) 3.5-11 期间迁移到前脑。对 LHRH 神经元正常发育的检查表明，大脑中存在 LHRH 神经元迁移的两条主要途径。 LHRH神经元迁移的主要途径很大程度上对应于嗅觉相关纤维的走向。在该通路的最尾部水平，即间隔区发育的地方，许多 LHRH 神经元向腹侧视前区方向转向腹侧。这些 LHRH 神经元偏离嗅觉相关纤维。 LHRH 神经元从神经纤维中分散意味着另一个引导信号有助于 LHRH 神经元向视前区迁移。根据这些发现，提出视前区的 LHRH 神经元的特征与间隔区的 LHRH 神经元的特征不同。为了检查 LHRH 神经元的出生日期是否影响其最终位置，将单剂量的 BrdU 注射到不同阶段的卵中。在E2.5-4.5出生的LHRH神经元在E11.5和E18.5的整个最终分布区域中被发现。相反，在 E5.5-6.5 出生的 LHRH 神经元在腹侧视前区没有观察到。晚期产生的 LHRH 神经元可能无法朝视前区方向移动。当晚期生成的 LHRH 神经元向视前区迁移时，LHRH 神经元迁移的结构和化学引导底物可能会丢失。Netrin-1 是一种引导各种轴突和细胞迁移的可扩散分子。在 E7.5，Netrin-1 mRNA 在下丘脑腹侧强烈表达，但在背内侧前脑中不表达。 Netrin-1可能是LHRH神经元从背侧中隔区迁移到腹侧视前区的候选分子。