The Central Distribution of Primary Afferents from the External Eyelids, Conjunctiva, and Cornea in the Rabbit, Studied Using WGA-HRP and B-HRP as Transganglionic Tracers
The Central Distribution of Primary Afferents from the External Eyelids, Conjunctiva, and Cornea in the Rabbit, Studied Using WGA-HRP and B-HRP as Transganglionic Tracers
复制标题
使用 WGA-HRP 和 B-HRP 作为跨神经节示踪剂研究兔外眼睑、结膜和角膜初级传入神经的中心分布
作者：
J. J. Ham;C. Yeo
我们分析了传入肢体的眨眼和瞬膜反应的兔子跟踪的中央分布的初级传入从眶周皮肤，结膜，角膜使用辣根过氧化物酶凝集小麦胚芽（WGA-HRP）或共轭类霍乱毒素（B-HRP）作为transganglionic示踪剂。眶周皮肤和结膜的传入纤维主要分布于三叉神经脊束核尾侧部（Vc）和脊髓C1段后角（dhC 1）。这些传入终止主要在板IIo和IIi和更弱的相邻板I和III。有弱得多的投射到脊髓段C2，嘴侧Vc，和相邻的网状结构（层IV和V）和三叉神经脊束核（Vi）的极间部的外侧部分。在三叉神经系统的吻侧分支中没有看到结膜初级传入。来自眶周皮肤的弱传入输入存在于三叉神经脊束核（Vo）的口部和三叉神经主核（Vp）的腹侧。角膜传入神经分布最密集的腹侧部分的Vi和三叉神经束内的神经岛在Vi的水平。它们还投射到尾侧Vc和邻近的dhC 1在板层I，II和III。Vp的腹侧部和背侧部以及Vo的腹侧部有稀疏的投射。邻近腹侧Vi的网状区域也接收一些角膜传入。WGA-HRP和B-HRP标记的终末在大部分区域分布相似，但Vc Ⅰ层接受WGA-HRP标记的终末，Vp和Vo只接受B-HRP标记的皮肤传入。由于三叉神经系统的所有分支都接受眼周和角膜的传入输入，我们认为所有这些分支都可能参与兔的反射性眨眼。
We have analyzed the afferent limb of the eyeblink and nictitating membrane response of the rabbit by tracing the central distribution of primary afferents from the periorbital skin, conjunctiva, and cornea using horseradish peroxidase agglutinated to wheat germ (WGA-HRP) or conjugated to choleragenoid (B-HRP) as transganglionic tracers. Afferents in the periorbital skin and conjunctiva distribute most heavily to pars caudalis of the spinal trigeminal nucleus (Vc) and to the dorsal horn of spinal segment C1 (dhC1). These afferents terminate predominantly in laminae IIo and IIi and more weakly to the adjacent laminae I and III. There are much weaker projections to spinal segment C2, rostral Vc, and adjacent reticular formation (laminae IV and V) and to the lateral part of pars interpolaris of the spinal trigeminal nucleus (Vi). No conjunctival primary afferents were seen in the rostral divisions of the trigeminal system. Weak afferent inputs from the periorbital skin are present ventrally in pars oralis of the spinal trigeminal nucleus (Vo) and in the principal trigeminal nucleus (Vp). Corneal afferents distribute most densely in the ventral part of Vi and in islands of neuropil within the trigeminal tract at the level of Vi. They also project to caudal Vc and the adjacent dhC1 in laminae I, II, and III. There are sparse projections to the ventral and dorsal parts of Vp and to the ventral part of Vo. Reticular areas adjacent to ventral Vi also receive a few corneal afferents. WGA-HRP- and B-HRP-labeled terminals were distributed similarly in most areas, but lamina I of Vc received terminals labeled with WGA-HRP and Vp and Vo received cutaneous afferents labeled with B-HRP only. Since all subdivisions of the trigeminal system receive periocular and corneal afferent inputs, we suggest that all these subdivisions may be involved in reflex eyeblinks in the rabbit.