Clarke D J, Gage F H, Björklund A
Brain Res. 1986 Mar 26;369(1-2):151-62. doi: 10.1016/0006-8993(86)90523-8.
The ultrastructural features of the contacts established by intrahippocampal grafts of foetal septal/diagonal band neurones in the dentate gyrus and the CA1 region of the previously denervated host hippocampus have been analysed with electron microscopic immunocytochemistry using a monoclonal antibody to choline acetyltransferase (ChAT). The results show that the grafted ChAT-positive neurones are capable of forming extensive synaptic contacts with neuronal targets in areas of the dentate gyrus and CA1 which normally receive such innervation. While all types of contacts normally found in association with the granule and pyramidal cell layers were also present in the graft-reinnervated specimens, the quantitative relationship between somatic and dendritic synapses was abnormal. Thus, the ChAT-immunoreactive synapses on cell bodies, which amounted to only a few percent in the normal animal, constituted over 60% in the grafted animals. Conversely, synapses on dendrites which constituted over 90% in the normal dentate were reduced to less than 40% in the grafted animals. The postsynaptic targets of the graft-derived cholinergic synapses included dendrites and cell bodies of dentate granule cells and CA1 pyramidal cells. This supports previous electrophysiological studies and indicates that the septal grafts may be able to modulate host hippocampal function via direct efferent connections onto the granule and pyramidal neurons in the host hippocampal formation.
利用抗胆碱乙酰转移酶（ChAT）单克隆抗体，通过电子显微镜免疫细胞化学方法，分析了胎儿隔区/斜角带神经元海马内移植到去神经支配的宿主海马齿状回和CA1区所建立联系的超微结构特征。结果显示，移植的ChAT阳性神经元能够与齿状回和CA1区中通常接受此类神经支配区域的神经元靶点形成广泛的突触联系。虽然在移植重新支配的标本中也存在与颗粒细胞层和锥体细胞层相关的所有正常类型的联系，但体细胞突触和树突突触之间的数量关系是异常的。因此，在正常动物中仅占百分之几的细胞体上的ChAT免疫反应性突触，在移植动物中占比超过60%。相反，在正常齿状回中占比超过90%的树突突触，在移植动物中减少到不足40%。移植来源的胆碱能突触的突触后靶点包括齿状颗粒细胞和CA1锥体细胞的树突和细胞体。这支持了先前的电生理研究，并表明隔区移植可能能够通过直接传出连接到宿主海马结构中的颗粒神经元和锥体细胞来调节宿主海马功能。
