The structure of the diencephalic prepacemaker nucleus revisited: light microscopic and ultrastructural studies.
The structure of the diencephalic prepacemaker nucleus revisited: light microscopic and ultrastructural studies.
复制标题
重新审视间脑前起搏核的结构：光学显微镜和超微结构研究。
DOI：
10.1002/cne.903230408
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Heiligenberg,W
中科院分区：
文献类型：
--
作者：
Zupanc,GK;Heiligenberg,W
前起搏核（PPn）是位于间脑和中脑交界处的一组神经元，控制着弱电刀鱼（Eigenmannia sp.）电器官放电的频率调制。以往的光学显微镜研究采用辣根过氧化物酶逆行标记表明，PPn局限于一个小的区域，位于第三脑室外侧约400 μm，并在其内侧边缘与丘脑中央后核（CP）融合。在本研究中，我们使用菜豆-白细胞凝集素和霍乱毒素作为高度敏感的标记物。与以前的研究相比，这些实验不仅在传统定义的PPn区域，而且在远至CP的区域产生了大量的标记细胞。由于PPn已被定义为逆行标记，而不是地形标准，这一结果的问题，PPn和CP之间的传统分离。这一观点与尼氏染色切片在光镜水平上的观察结果以及PPn和CP中细胞体在超微结构水平上的几种形态学特征的定量分析一致。两组实验都没有发现两种原子核之间的差异。此外，放射自显影研究表明，即使在成年期，细胞连续出生在脑室区的CP，至少有一些这些新生细胞分化成CP细胞和迁移横向向PPn。因此，我们假设CP和PPn形成一个大的复合体，内侧CP提供外侧CP和PPn神经元的前体。© 1992 Wiley利斯公司
The prepacemaker nucleus (PPn), a bilateral cluster of neurons at the boundary of diencephalon and mesencephalon, controls frequency modulations of the electric organ discharge in weakly electric knifefish (Eigenmannia sp.). Previous light microscopic studies employing retrograde labelling with horseradish peroxidase suggested that the PPn is restricted to a small area, located approximately 400 μm laterally from the third ventricle and fusing at its medial edge with the thalamic central posterior nucleus (CP). In the present investigation we usedPhaseolus vulgaris‐leucoagglutinin and cholera toxin as highly sensitive markers. In contrast to the previous studies, these experiments yielded a large number of labelled cells not only in the region of the traditionally defined PPn but also in an area reaching far into the CP. Since the PPn has been defined by retrograde labelling rather than by topographic criteria, this result questions the traditional separation between PPn and CP. Such a notion is in agreement with observations of Nissl‐stained sections at the light microscopic level and with a quantitative analysis of several morphological characteristics of the cell bodies in the PPn and CP at the ultrastructural level. Both sets of experiments failed to find differences between the two nuclei. Furthermore, autoradiographic studies have shown that, even in adulthood, cells are continuously born within the ventricular zone of the CP, and at least some of these newborn cells differentiate into CP cells and migrate laterally towards the PPn. Therefore, we postulate that CP and PPn form one large complex, with the medial CP providing precursors of neurons in the lateral CP and PPn. © 1992 Wiley‐Liss, Inc.