Clarke D J, Gage F H, Nilsson O G, Björklund A
J Comp Neurol. 1986 Oct 22;252(4):483-92. doi: 10.1002/cne.902520405.
A group of aged, behaviorally impaired rats received suspension grafts of fetal septal-diagonal band tissue into the otherwise intact hippocampal formation. Three months after grafting, behaviorally recovered rats were studied by immunocytochemistry by using monoclonal antibodies to choline acetyltransferase (ChAT) and electron microscopy. The innervation of the host dentate gyrus by graft-derived ChAT-positive fibres was unmasked by acute removal of the intrinsic septal cholinergic innervation by fimbria-fornix transection 5-7 days before perfusion. The pattern of termination and ultrastructural connectivity were compared with previous results obtained from both young nonoperated control animals and a group of young rats with intrahippocampal septal grafts that had been subjected to denervation of the intrinsic cholinergic input at the time of transplantation. Graft-derived, ChAT-immunoreactive terminals formed abundant synaptic specializations with neuronal elements in the host dentate gyrus. The predominant postsynaptic target (about 65% of all boutons) was dendritic shafts, whereas about 20% of the boutons contacted dendritic spines. Very few synapses onto neuronal perikarya were found in the grafted aged rats. In some of these cases, however, it was possible to identify the target as dentate granule cells. This situation is very similar to that seen in young control rats but significantly different than the distribution observed in the denervated young grafted group, where axosomatic contacts predominated. The results indicate that the graft-induced behavioral improvement seen in the aged rats may depend on the formation of functional cholinergic graft connections with neuronal elements in the host hippocampal formation.
一组行为受损的老年大鼠接受了胎儿隔区-斜角带组织的悬浮移植，移植到原本完整的海马结构中。移植三个月后，通过使用抗胆碱乙酰转移酶（ChAT）单克隆抗体的免疫细胞化学和电子显微镜对行为恢复的大鼠进行研究。在灌注前5-7天通过海马伞横断急性去除内源性隔区胆碱能神经支配，从而揭示移植来源的ChAT阳性纤维对宿主齿状回的神经支配。将终止模式和超微结构连接性与先前从年轻未手术对照动物以及一组在移植时已接受内源性胆碱能输入去神经支配的年轻大鼠海马内隔区移植获得的结果进行比较。移植来源的ChAT免疫反应性终末与宿主齿状回中的神经元成分形成了丰富的突触特化。主要的突触后靶点（约占所有终扣的65%）是树突干，而约20%的终扣与树突棘接触。在移植的老年大鼠中发现极少的突触与神经元胞体相连。然而，在其中一些情况下，可以确定靶点为齿状颗粒细胞。这种情况与年轻对照大鼠中观察到的非常相似，但与去神经支配的年轻移植组中观察到的分布显著不同，在后者中轴体接触占主导。结果表明，在老年大鼠中观察到的移植诱导的行为改善可能取决于与宿主海马结构中的神经元成分形成功能性胆碱能移植连接。
