前庭神经核纤维与投射至纹状体的束旁核神经元的突触联系

目的：观察发自前庭神经内侧核的纤维末梢与投射至纹状体的丘脑束旁核神经元的突触联系。方法：采用15只Wistar大鼠，应用顺行和逆行标记技术，免疫组织化学和免疫电镜方法。结果：将CTb单侧注入纹状体，同时将BDA注入同侧的前庭神经内侧核。在束旁核发现了CTb标记神经元和BDA标记轴突终末，BDA标记纤维和终末存在于外侧束旁核整个长度的背侧2／3区，而CTb标记神经元也存在于外侧束旁核背侧2／3区，2种标记相互重叠。电镜下可见标记终末与标记神经元形成非对称性的轴-体和轴-树突触。结论：由前庭神经内侧核发出的投射纤维在束旁核与投射至纹状体的束旁核神经元之间存在着非对称性的突触联系。

Synaptic contacts in parafascicular nucleus between vestibulothalamic fibers and neurons of thalamus projecting to striatum

Objective: To observe the vestibular fibers making synaptic contacts with neurons of the parafascicular nucleus (PF) projecting to the striatum. Methods: With anterograde and retrograde tracing techniches, ipsilateral injections of cholera toxin B subunit (CTb) into the striatum and biotinylated dextranamine (BDA) into the medial vestibular nucleus (MVe) were made stereotaxically in 15 Wistar rats. Results: In PF,where good overlapping distributions of CTb-labeled neurons and BDA-labeled axon terminals were found. The BDA-labeled fibers and terminals were found bilaterally with an ipsilateral dominance in the dorsal two-third of the lateral PF throughout its rostrocaudal extent. The CTb-labeled neurons were also distributed ipsilaterally in the dorsal two-third of the lateral PF. The distribution area of BDA-labeled axons overlapped with that of CTb-labeled neurons in the dorsal two thirds of the lateral PF. At electron microscopic level, BDA-labeled terminals were found to make synaptic contacts with CTb-labeled neuron, the contacts were both axodendritic and axosomatic. Conclusion: The vestibular fibers make synaptic contacts with neurons of the PF sending their axons to the striatum.