Cao C Q, Djouhri L, Brown A G
Department of Preclinical Veterinary Sciences, University of Edinburgh, Summerhall, U.K.
Neuroscience. 1993 Nov;57(1):153-65. doi: 10.1016/0306-4522(93)90117-x.
Lumbosacral spinal neurons activated via the spinocervical tract were stained by intracellular injection of horseradish peroxidase in cats anaesthetized with chloralose and paralysed with gallamine triethiodide. The neurons were activated orthodromically by single shock stimulation of the ipsilateral dorsolateral funiculus at the second to third cervical segment, but not from the rostral part of the first cervical segment. Twenty nine cells were recovered from the histological material and subsequently reconstructed from transverse sections. Sixteen cells (55%) had axons that projected ipsilaterally to the lateral funiculus and their somata were located in two regions of the spinal cord, one group in the dorsal horn (laminae IV-V) and the other in the intermediate gray matter (laminae VI-VII). The axons of 10 of these cells gave off collaterals, and in seven of them the collaterals ramified in the grey matter deep to the cell body. The axons of five cells (17%) projected medially towards the central canal, four crossing the mid line in the ventral white commissure and ascending in the contralateral ventral funiculus. Only one of these cells had an axon collateral that crossed into the contralateral dorsal horn. Of the remaining eight cells, three had no obvious long axons but had many local axon collaterals, the axons of three cells were not stained, one had an axon projecting towards the ipsilateral ventral funiculus and one was a motoneuron and its axon projected into a ventral root. A feature of the dendritic trees of many cells was their wide spread in the mediolateral and/or the dorsoventral directions, although no dendrites reached dorsally into lamina II. Twenty-two cells (76%) were excited by moving hairs and by noxious pinch, three (10%) by hair movement alone, two (7%) by noxious pinch and pressure, and for two cells (7%) no receptive field could be found. It is concluded that not only postsynaptic dorsal column neurons receive input from the spinocervical tract but also other cells in the dorsal and ventral horns and the intermediate gray matter. Possible identities for these cells are discussed.
在用氯醛糖麻醉并用三碘季铵酚麻痹的猫中，通过辣根过氧化物酶的细胞内注射对经脊髓颈段通路激活的腰骶脊髓神经元进行染色。通过对第二至第三颈段同侧背外侧索进行单次电休克刺激可正向激活这些神经元，但第一颈段头端部分的刺激则不能。从组织学材料中回收了29个细胞，并随后从横切片进行重建。16个细胞（55%）的轴突向同侧外侧索投射，其胞体位于脊髓的两个区域，一组位于背角（IV - V层），另一组位于中间灰质（VI - VII层）。其中10个细胞的轴突发出侧支，7个细胞的侧支在胞体深部的灰质中分支。5个细胞（17%）的轴突向内侧朝向中央管投射，4个在腹侧白质连合处交叉中线并在对侧腹侧索中上行。这些细胞中只有1个有轴突侧支交叉进入对侧背角。其余8个细胞中，3个没有明显的长轴突但有许多局部轴突侧支，3个细胞的轴突未被染色，1个细胞的轴突向同侧腹侧索投射，1个是运动神经元，其轴突投射到腹根。许多细胞的树突树的一个特点是它们在内外侧和/或背腹侧方向广泛分布，尽管没有树突向背侧延伸到II层。22个细胞（76%）对毛发移动和有害捏压有反应，3个（10%）仅对毛发移动有反应，2个（7%）对有害捏压和压力有反应，2个细胞（7%）未发现感受野。结论是，不仅突触后背柱神经元接受来自脊髓颈段通路的输入，背角和腹角以及中间灰质中的其他细胞也接受输入。讨论了这些细胞可能的身份。
