STRUCTURAL BASIS OF NEURON-TO-NEURON CROSS-EXCITATION IN DORSAL-ROOT GANGLIA
STRUCTURAL BASIS OF NEURON-TO-NEURON CROSS-EXCITATION IN DORSAL-ROOT GANGLIA
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DOI：
10.1007/bf01262054
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发表时间：
1994-09-01
期刊：
影响因子：
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通讯作者：
DEVOR, M
中科院分区：
文献类型：
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作者：
SHINDER, V;DEVOR, M
镧被用作示踪物质，以确定背根神经节细胞外空间中的小分子是否可以进入将感觉神经元与周围的卫星细胞鞘分开的狭窄裂隙。结果表明，镧能够扩散到这个裂隙中，特别是当组织在固定前与示踪剂孵育时。镧进入了相邻卫星细胞突起交汇处的缝隙。在轴突丘-起始节段区域似乎有优先通路。大直径的光神经元通常支持快速传导的有髓轴突，并携带关于非伤害性感觉事件的信息，事实证明，大直径的暗神经元比小直径的暗神经元更有可能接纳镧，后者往往有细的有髓和无髓轴突，通常携带伤害性信息。周围神经切断后，镧进入神经元-卫星细胞裂隙的通道减少。这些数据支持背根神经节内非突触细胞间交叉兴奋的机制，特别是支持这种相互作用是通过化学方式而不是电子方式进行的假说。
Lanthanum was used as a tracer substance to determine whether small molecules in the bulk extracellular space in dorsal root ganglia have access to the narrow cleft that separates sensory neurons from their surrounding satellite cell sheath. Results showed that lanthanum is able to diffuse into this cleft, especially when the tissue is incubated with the tracer before fixation. Lanthanum gained access to the cleft at the seam where adjacent satellite cell processes meet. There appears to be preferential access in the axon hillock-initial segment region. Large diameter light neurons, which generally support fast conducting myelinated axons and carry information about non-nociceptive sensory events, proved more likely to admit lanthanum than small diameter dark neurons, which tend to have thin myelinated and unmyelinated axons and typically carry nociceptive information. Peripheral axotomy triggered a reduction in the access of lanthanum to the neuron-satellite cell cleft. These data bear on the mechanism of non-synaptic cell-to-cell cross-excitation within dorsal root ganglia, and in particular, lend support to the hypothesis that this interaction is mediated chemically rather than electrically.