猫丘脑中央外侧核内脊丘系终末与丘脑-皮质投射神经元之间的突触联系

THE SYNAPTIC CONNECTIONS BETWEEN THE SPINOTHALAMIC TERMINALS AND THALAMOCORTICAL PROJECTING NEURONS IN THE CENTRAL LATERAL NUCLEUS (CL) OF THE CAT

本实验应用顺行溃变和HRP逆行追踪相结合的方法，首次在电镜水平对猫丘脑中央外侧核内脊丘系终末与丘脑-皮质投射神经元之间的突触联系进行了研究．在脊髓第4颈段刀切损毁一侧侧索和前索后，将HRP注射于同侧大脑前上薛氏回和中上薛氏回前端。在电镜下于损毁同侧中央外侧核内可见下列突触连结：（1）溃变的脊丘系轴突终末与标记树突形成的轴-树突触；（2）溃变的脊丘系轴突终末与非标记树突形成的轴-树突触，个别非标记树突含有突触小泡；（3）正常的轴突终末与HRP标记树突和胞体形成的轴-树突触和轮一体突触；（4）正常的两个轴突终末与HRP标记树突形成的轴-轴-树连续性突触；（5）非标记的含突触小泡的突触前树突与HRP标记树突形成的树-树突触。同时可见大量汇聚型突触复合体。本文首次报道在丘脑中央外侧核内，脊丘系终末与丘脑-皮质投射神经元之间存在着直接的突触联系。

The synaptic relationship between the spinothalamic terminals (STTs) and the thalamocortical projecting neurons(TCPNs) in the central lateral nucleus (CL) was firstly studied by combining anterograde degeneration and retrograde HRPtracing method. The lateral and the ventral funiculi of cat were sectioned at the fourth cervical segment of spinal cord oneside. Two or three days later the HRP was injected into the anterior suprasylvian gyrus and middle suprasylvian gyrus on thelesion side. After this operation for two days, the animals were perfused and the sections containing the TCPNs were prepared for electron microscopy. The following synaptic patterns were found in the CL on operation side: (1) DegeneratingSTTs made axo-dendritic synapses with HRP labelled TCPNs dendrites. (2)Degenerating STTs made axo-dendritic synapses with unlabelled dendrites, which occasionally contained synaptic vesicles. (3) Normal axonal terminals made axo-dendritic and axo-somatic synapses with HRP labelled TCPNs. (4) Two normal axonal termi nals made axo-axo-dendritic synapseswith HRP labelled TCPNs dendrite. (5 )Unlabelled presynaptic dendrites containing synaptic vesicles made dendrodendriticsynapses with HRP labelled TCPNs dendrites. Besides, there were numerous aggregated synaptic complexes in the CL.This study firstly reported the synaptic connection between the STTs and TCPNs in the CL.