TRIGEMINAL PROJECTIONS TO CONTRALATERAL DORSAL HORN - CENTRAL EXTENT, PERIPHERAL ORIGINS, AND PLASTICITY
TRIGEMINAL PROJECTIONS TO CONTRALATERAL DORSAL HORN - CENTRAL EXTENT, PERIPHERAL ORIGINS, AND PLASTICITY
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DOI：
10.3109/08990229009144705
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发表时间：
1990-01-01
影响因子：
0.9
通讯作者：
RHOADES, RW
中科院分区：
文献类型：
--
作者：
JACQUIN, MF;CHIAIA, NL;RHOADES, RW
先前的研究已经证明了猫、仓鼠和大鼠的三叉神经（V）下颌初级传入投射到对侧延髓和颈后角的背内侧部分。我们现在报告了大鼠对侧脊髓和颈后角腹外侧部分存在更实质性的V眼初级传入投射。辣根过氧化物酶（HRP）注射到V神经节或V脑干复合体顺行标记的初级传入轴突，退出尾侧腹外侧V脊髓束，形成一个rostracaudally连续的，横向取向，V初级传入交叉束。这些纤维终止于对侧延髓尾侧腹外侧背角的第III-V层和第一、第二颈段。二脒基黄（DY）或荧光金逆行追踪和顺行追踪菜豆白细胞凝集素也表现出实质性的连合投影的中央起源在髓背角板I-VII。后者的投影有一个更广泛的轨迹和终止模式比V初级传入交叉。单侧HRP注射到延髓和颈后角也逆行标记V初级传入侧支对侧的注射部位在相应的区域的背角，也在腹内侧interpolaris，oralis，principalis，喙交叉。轴突（1.5 . ±. 0.8平均直径为0.4-3.9 μ m;范围为0.4-3.9 μ m），因此终止于其来源细胞的同侧和对侧。这些HRP注射也标记了平均40.4 ±。13.0 V神经节细胞（平均值±.对侧神经节的背内侧、眼区中的分裂胞体校正）。它们的平均直径略大于同侧标记的细胞的平均直径（29.9 vs 26.3 μ m）。双标记研究评估了可能的眼受体表面神经支配的中央交叉初级传入。将DY注射到右侧延髓和颈后角，将HRP应用于左侧角膜、筛神经或覆盖大脑皮质的硬脑膜。虽然DY标记了每只动物75至125个左侧神经节细胞，但没有细胞被双重标记。所有这些结果表明，伤害性感觉特异性神经节细胞不是交叉眼初级传入投射的来源。
Prior studies have documented a trigeminal (V) mandibular primary afferent projection to the dorsomedial portion of the contralateral medullary and cervical dorsal horns in cat, hamster, and rat. We now report the existence of a much more substantial V ophthalmic primary afferent projection to the ventrolateral portion of contralateral medullary and cervical dorsal horns in rats. Horseradish peroxidase (HRP) injections into the V ganglion or V brainstem complex anterogradely labeled a fascicle of primary afferent axons that exited the caudal ventrolateral V spinal tract to form a rostracaudally continuous, transversely oriented, V primary afferent decussation. These fibers terminated most heavily in laminae III-V of the ventrolateral dorsal horn in contralateral caudal medulla and the first and second cervical segments. Retrograde tracing with diamidino yellow (DY) or fluorogold and anterograde tracing with Phaseolus vulgaris leucoagglutinin also demonstrated a substantial commissural projection of central origin in medullary dorsal horn laminae I-VII. The latter projection had a more diffuse trajectory and termination pattern than that of the V primary afferent decussation. Unilateral HRP injections into medullary and cervical dorsal horns also retrogradely labeled V primary afferent collaterals contralateral to the injection site in corresponding regions of dorsal horn, and also in ventromedial interpolaris, oralis, and principalis, rostral to their decussation. Axons (1.5 .+-. 0.8 .mu.m mean diameter; 0.4-3.9 .mu.m range) therefore terminated both ipsi- and contralateral to their cells of origin. These HRP injections also labeled an average of 40.4 .+-. 13.0 V ganglion cells (mean .+-. SD, corrected for split somata) in dorsomedial, ophthalmic regions of the contralateral ganglion. Their mean diameter was slightly larger than that of cell labeled ipislaterally (29.9 vs 26.3 .mu.m). Double-labeling studies assessed possible ophthalmic receptor surfaces innervated by centrally crossing primary afferents. DY was injected into right medullary and cervical dorsal horns, and HRP was applied to either the left cornea, the ethmoid nerve, or the dura overlying cerebral cortex. Though DY labeled from 75 to 125 left ganglion cells per animal, no cells were double-labeled. All of these findings suggest that nociceptive-specific ganglion cells are not a source of the crossed ophthalmic primary afferent projection.