Zimmer J, Laurberg S, Sunde N
Exp Brain Res. 1986;64(1):158-68. doi: 10.1007/BF00238212.
The acetylcholinesterase (AChE) activity of the rat hippocampus and fascia dentata depends on an intact septohippocampal connection, and histochemical staining for AChE is commonly used to monitor the distribution of the cholinergic septohippocampal projection. It is also characteristic that the laminae of low or moderate to dense AChE staining in the hippocampus and fascia dentata coincide with the terminal fields of the major non-cholinergic, afferent pathways. While studying lesion-induced collateral sprouting and aberrant axonal growth of these pathways we observed that the AChE staining pattern changed in accordance with the reorganized distribution of the non-cholinergic pathways, and this occurred even without direct interfering with the septohippocampal projection itself. Widening and narrowing of the medial perforant path and mossy fiber terminal zones thus resulted in corresponding changes in the bands of AChE staining normally associated with these zones. Expansion of the commissural-associational hippocampodentate projections and the lateral perforant path was in a similar way paralleled by a widening of the AChE-poor zones which normally overlap with the termination of these projections. Observations of the same kind were made in intracerebral transplants of fascia dentata innervated by various host afferents, and in rats subjected to neonatal X-irradiation, where the mossy fiber projection is reduced and aberrant perforant pathways project into CA3 due to a reduced formation of granule cells. The observed sets of changes with linkage between the different non-cholinergic projections and the activity of AChE in their respective terminal fields were accordingly reproduced under several different experimental conditions. It could not be explained alone by interaction between the septal afferents and their target cells. We therefore conclude that the density and laminar distribution of the AChE activities within the hippocampus and fascia dentata are determined at least in part by the major afferent, non-cholinergic nerve connections. We suggest that the effect occurs through direct axonal interaction or through changes in the receptiveness of the common dentate and hippocampal target cells.
大鼠海马和齿状回的乙酰胆碱酯酶（AChE）活性依赖于完整的隔海马连接，AChE的组织化学染色常用于监测胆碱能隔海马投射的分布。海马和齿状回中低或中度至密集AChE染色的层与主要非胆碱能传入通路的终末场重合也是其特征。在研究这些通路的损伤诱导侧支发芽和异常轴突生长时，我们观察到AChE染色模式根据非胆碱能通路的重新分布而改变，即使在没有直接干扰隔海马投射本身的情况下也会发生这种情况。内侧穿通通路和苔藓纤维终末区的增宽和变窄因此导致通常与这些区域相关的AChE染色带发生相应变化。连合-联合海马齿状回投射和外侧穿通通路的扩张同样伴随着AChE缺乏区的增宽，这些区域通常与这些投射的终末重叠。在由各种宿主传入神经支配的齿状回脑内移植中，以及在新生大鼠接受X射线照射的情况下也观察到了类似的现象，在新生大鼠中，由于颗粒细胞形成减少，苔藓纤维投射减少，异常的穿通通路投射到CA3区。在几种不同的实验条件下，相应地再现了不同非胆碱能投射与其各自终末场中AChE活性之间的观察到的一系列变化。这不能仅通过隔传入神经与其靶细胞之间的相互作用来解释。因此，我们得出结论，海马和齿状回内AChE活性的密度和层状分布至少部分由主要的传入非胆碱能神经连接决定。我们认为这种效应是通过直接的轴突相互作用或通过共同的齿状回和海马靶细胞接受性的变化而发生的。
