Tokuno H, Nakamura Y
Department of Anatomy, School of Medicine, Kanazawa University, Japan.
Brain Res. 1987 Dec 8;436(1):76-84. doi: 10.1016/0006-8993(87)91558-7.
The relationships between nigrotectal terminals and tectospinal neurons in the deep layers of the superior colliculus have been examined light and electron microscopically by using antero- and retrograde transport of tracer, and anterograde degeneration. For light microscopy, horseradish peroxidase (HRP) was injected into the cervical spinal cord, and HRP conjugated to wheat germ agglutinin (WGA-HRP) into the substantia nigra at the same time. It appeared that about 22% of the retrogradely labeled tectospinal neurons were totally or partially in the anterogradely labeled nigral terminal clusters. This coexistence was particularly manifest in the dorso-lateral part of the intermediate gray layer. For electron microscopy, nigral lesions and HRP injections into the cervical spinal cord were combined in the same animals. Degenerating nigrotectal terminals were found in both axosomatic and axodendritic symmetrical synaptic contacts with retrogradely labeled tectospinal neurons in the intermediate gray layer. Present experiments show tectospinal neurons receiving monosynaptic input from the substantia nigra do exist in the intermediate gray layer of the superior colliculus, especially in its dorsolateral portion.
利用示踪剂的顺行和逆行运输以及顺行性变性，通过光镜和电镜检查了黑质顶盖终末与上丘深层顶盖脊髓神经元之间的关系。在光镜检查中，将辣根过氧化物酶（HRP）注入颈脊髓，同时将与小麦胚芽凝集素结合的HRP（WGA-HRP）注入黑质。结果显示，约22%的逆行标记的顶盖脊髓神经元全部或部分位于顺行标记的黑质终末簇中。这种共存现象在中间灰质层的背外侧部分尤为明显。在电镜检查中，对同一动物进行黑质损伤并向颈脊髓注射HRP。在中间灰质层中，发现变性的黑质顶盖终末与逆行标记的顶盖脊髓神经元形成轴-体和轴-树突的对称性突触联系。目前的实验表明，上丘中间灰质层，特别是其背外侧部分，确实存在接受来自黑质单突触输入的顶盖脊髓神经元。
