Slice cultures as a model to study entorhinal‐hippocampal interaction
Slice cultures as a model to study entorhinal‐hippocampal interaction
复制标题
切片培养物作为研究内嗅-海马相互作用的模型
作者：
B. Heimrich;M. Frotscher
研究海马切片培养物的研究人员对这种体外系统中发生的高度器官型分化印象深刻（例如，Gahwiler，1981年，1984年a，1984年b; Zimmer和Gahwiler，1984年; Frotscher等人，1990; Heimrich和Frotscher，1991; Stoppini等人，1991年）。为了监测单个海马神经元的细胞特异性分化，我们最近应用了高尔基体技术，该技术染色单个神经元的大部分过程。高尔基体浸渍的制备物可以容易地通过金色调（gold-toning）达到电子显微镜水平（Fairen等人，1977年）。这使我们能够通过光学和电子显微镜研究切片培养物中鉴定的海马细胞的分化（Frotscher等人，1990; Heimrich和Frotscher，1991）。我们的光学显微镜高尔基体分析的结果，证实并扩展了以前的细胞内标记研究（Gahwiler，1984 a; Zimmer和Gahwiler，1984），可以总结如下：海马主细胞，锥体神经元和颗粒细胞，形成马蹄形细胞层的特点，就像他们在原位。邻近的树突状区，即海马体中的放射层和定向层以及齿状筋膜的分子层也发育。然而，这些区域比正常区域小，可能是由于在培养条件下细胞层变宽。同时浸渍的许多锥体细胞和颗粒细胞在单一的文化，使我们能够得出结论，他们的树突状树的定向在一个类似的方式从许多原位研究。然而，观察到一些差异。因此，细胞体的分布较松散，很可能是由于培养物变平和切片制备过程中受损的一些神经元死亡。特别是在CA 1中，这导致细胞之间的更多空间被广泛的水平和基底树突状乔木填充（Frotscher等人，1990年）。这些啮齿动物海马切片培养物中的CA 1区与灵长类动物原位脑中的CA 1区非常相似，其中胞体不形成密集的锥体层。我们已经解释了我们的观察结论，在大鼠的锥体细胞有能力形成一个类似的复杂的水平和基底树突乔木观察这些细胞在灵长类动物的大脑。然而，大鼠锥体神经元原位的密集包装不允许这种复杂的树突状模式的发展。
Investigators working with slice cultures of hippocampus were impressed by the high degree of organotypic differentiation that takes place in this in vitro system (e.g., Gahwiler, 1981, 1984a, 1984b; Zimmer and Gahwiler, 1984; Frotscher et al., 1990; Heimrich and Frotscher, 1991; Stoppini et al., 1991). In order to monitor the cell-specific differentiation of individual hippocampal neurons, we have recently applied the Golgi technique, which stains single neurons with the majority of their processes. Golgi-impregnated preparations can easily be taken to the electron microscopic level by gold-toning (Fairen et al., 1977). This allowed us to study the differentiation of identified hippocampal cells in slice cultures both by light and electron microscopy (Frotscher et al., 1990; Heimrich and Frotscher, 1991). The results of our light microscopic Golgi analysis, which confirmed and extended previous intracellular labeling studies (Gahwiler, 1984a; Zimmer and Gahwiler, 1984), can be summarized as follows: Hippocampal principal cells, pyramidal neurons and granule cells, form the characteristic horseshoe-shaped cell layers like they do in situ. The adjacent dendritic zones, that is, stratum radiatum and stratum oriens in the hippocampus proper and the molecular layer of the fascia dentata, develop as well. However, these zones were smaller than normal, probably due to the broadening of the cell layers under culture conditions. The simultaneous impregnation of many pyramidal cells and granule cells in single cultures allowed us to conclude that their dendritic trees were oriented in a similar way as known from numerous in situ studies. Nevertheless, some differences were observed. Thus, there was a looser distribution of cell bodies, most likely due to the flattening of the culture and the death of some neurons damaged during slice preparation. Particularly in CA1, this resulted in more space between the cells that was filled in by an extensive horizontal and basal dendritic arbor (Frotscher et al., 1990). The CA1 region in these slice cultures of rodent hippocampus resembled very much the CA1 region in the primate brain in situ, where the perikarya do not form a densely packed pyramidal layer. We have interpreted our observations by concluding that the pyramidal cells in the rat have the capacity of forming a similar complex horizontal and basal dendritic arbor as observed in these cells in the primate brain. However, the dense packing of rat pyramidal neurons in situ does not allow this complex dendritic pattern to develop.