CHANGES IN DORSAL HORN SYNAPTIC DISK NUMBERS FOLLOWING UNILATERAL DORSAL RHIZOTOMY
CHANGES IN DORSAL HORN SYNAPTIC DISK NUMBERS FOLLOWING UNILATERAL DORSAL RHIZOTOMY
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DOI：
10.1002/cne.902830410
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发表时间：
1989-05-22
影响因子：
2.5
通讯作者：
COGGESHALL, RE
中科院分区：
文献类型：
--
作者：
CHUNG, K;MCNEILL, DL;COGGESHALL, RE
本研究估计了单侧背根切断对侧大鼠S2背侧的I-IV板层的突触盘数和变性突触终末的数目。这些数据使我们能够估计初级传入突触的丢失，并将这种丢失与切断的S2背根近端残端的轴突消失速度相关联。我们的第一个发现是47%的同侧突触和27%的对侧突触在切断单侧神经根后的一天内消失。结论是，大鼠脊髓这一部分的主要突触群来自初级传入来源，背根纤维有广泛的双侧投射。对侧投射通过对侧大量变性终末的出现而得到证实。我们还发现，在I-UV板层，突触丢失和变性终末的出现是相对同步的。最后，我们发现突触丢失的时间进程主要与背根切断后近端无髓纤维的消失有关。
The present study estimates the numbers of synaptic discs and numbers of degenerating synaptic terminals in laminae I-IV of the rat S2 dorsal born ipsi-and contralateral to unilateral dorsal rhizotomy. These data allow us to estimate the loss of synapses of primary afferents and to correlate this loss with the rate of axon disappearance in the proximal stump of a transected S2 dorsal root. Our first findings are that 47% of the ipsilateral synapses and 27% of the contralateral synapses disappear within a day following unilateral rhizotomy. Conclusions are that the predominant synaptic population in this part of the rat spinal cord is of primary afferent origin and that there is an extensive bilateral projection of the dorsal root fibers. The contralateral projection is confirmed by the appearance of numerous degenerating terminals on the contralateral side. We also find that synaptic loss and appearance of degenerating terminals occur relatively synchronously in laminae I-UV. Finally we find that the time course of the synaptic loss correlates primarily with the disappearance of unmyelinated fibers in the proximal stump of the transected dorsal root.