Bevan M D, Crossman A R, Bolam J P
MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford, UK.
Brain Res. 1994 Oct 3;659(1-2):99-109. doi: 10.1016/0006-8993(94)90868-0.
The two major afferents of the entopeduncular nucleus are the subthalamic nucleus and the neostriatum, which have opposing physiological effects on entopeduncular neurons. Experiments were performed to test the hypothesis that individual entopeduncular neurons that project to the thalamus receive convergent synaptic input from both the subthalamic nucleus and the neostriatum in the rat. This was achieved using double anterograde tracing combined with retrograde tracing. In the electron microscope anterogradely labelled subthalamic (Subthalamic Type 1) and neostriatal terminals were observed to form asymmetrical and symmetrical synaptic contacts respectively, with all parts of entopeduncular neurons. Labelled subthalamic and neostriatal terminals were observed in convergent synaptic contact with entopeduncular neurons, some of which were retrogradely labelled from the thalamus. A second rarer type of terminal was labelled (Subthalamic Type 2) which formed symmetrical synaptic contacts with the proximal regions of unlabelled and retrogradely labelled entopeduncular neurons. These terminals are believed to be derived from the globus pallidus. It is concluded that the topographical and synaptic organization of the so-called direct (neostriatum to entopeduncular nucleus) and indirect pathways (involving the subthalamus and the globus pallidus) is capable of mediating the inhibition and excitation of output neurons in the entopeduncular nucleus that occur following neostriatal stimulation.
内苍白球核的两大传入神经是丘脑底核和新纹状体，它们对苍白球内核神经元具有相反的生理作用。进行了实验以验证大鼠中投射至丘脑的单个苍白球内核神经元接受来自丘脑底核和新纹状体的汇聚性突触输入这一假说。这是通过双顺行示踪结合逆行示踪来实现的。在电子显微镜下，顺行标记的丘脑底核（丘脑底核1型）和新纹状体终末分别与苍白球内核神经元的所有部分形成不对称和对称的突触联系。观察到标记的丘脑底核和新纹状体终末与苍白球内核神经元形成汇聚性突触联系，其中一些神经元是从丘脑逆行标记的。还标记了第二种较罕见的终末类型（丘脑底核2型），它与未标记和逆行标记的苍白球内核神经元的近端区域形成对称突触联系。这些终末被认为源自苍白球。得出的结论是，所谓的直接通路（从新纹状体到苍白球内核）和间接通路（涉及丘脑底核和苍白球）的拓扑和突触组织能够介导新纹状体刺激后苍白球内核输出神经元的抑制和兴奋。
