New J G, Northcutt R G
J Morphol. 1984 Nov;182(2):125-36. doi: 10.1002/jmor.1051820202.
Horseradish peroxidase histochemical studies of afferent and efferent projections of the trigeminal nerve in two species of chondrostean fishes revealed medial, descending and ascending projections. Entering fibers of the trigeminal sensory root project medially to terminate in the medial trigeminal nucleus, located along the medial wall of the rostral medulla. Other entering sensory fibers turn caudally within the medulla, forming the trigeminal spinal tract, and terminate within the descending trigeminal nucleus. The descending trigeminal nucleus consists of dorsal (DTNd) and ventral (DTNv) components. Fibers of the trigeminal spinal tract descend through the lateral alar medulla and into the dorsolateral cervical spinal cord. Fibers exit the spinal tract throughout its length, projecting to the ventral descending trigeminal nucleus (DTNv) in the medulla and to the funicular nucleus at the obex. Retrograde transport of HRP through sensory root fibers also revealed an ascending bundle of fibers that constitutes the neurites of the mesencephalic trigeminal nucleus, cell bodies of which are located in the rostral optic tectum. Retrograde transport of HRP through motor root fibers labeled ipsilateral cells of the trigeminal motor nucleus, located in the rostral branchiomeric motor column.
对两种软骨硬鳞鱼三叉神经传入和传出投射的辣根过氧化物酶组织化学研究揭示了内侧、下行和上行投射。三叉神经感觉根的传入纤维向内侧投射，终止于位于延髓前部内侧壁的内侧三叉神经核。其他传入感觉纤维在延髓内转向尾侧，形成三叉神经脊髓束，并终止于下行三叉神经核。下行三叉神经核由背侧（DTNd）和腹侧（DTNv）部分组成。三叉神经脊髓束的纤维穿过延髓外侧翼并进入颈脊髓背外侧。纤维在其全长范围内离开脊髓束，投射到延髓内的腹侧下行三叉神经核（DTNv）和闩部的索状核。通过感觉根纤维进行的辣根过氧化物酶逆行运输还揭示了一束上行纤维，其构成了三叉神经中脑核的神经突，其细胞体位于前部视顶盖。通过运动根纤维进行的辣根过氧化物酶逆行运输标记了位于前部鳃弓运动柱的同侧三叉神经运动核细胞。
