Regenerated synapses in lamprey spinal cord are sparse and small even after functional recovery from injury.
Regenerated synapses in lamprey spinal cord are sparse and small even after functional recovery from injury.
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DOI：
10.1002/cne.22368
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发表时间：
2010-07-15
期刊：
影响因子：
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通讯作者：
Morgan JR
中科院分区：
文献类型：
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作者：
Oliphint PA;Alieva N;Foldes AE;Tytell ED;Lau BY;Pariseau JS;Cohen AH;Morgan JR
尽管突触再生在脊髓损伤（SCI）后神经元功能恢复中发挥着潜在的重要作用，但关于再生突触形态的最基本问题仍未得到解答。因此，我们开始通过检查脊髓损伤行为恢复稳健的条件下再生突触的数量、分布、分子组成和超微结构来更好地了解中枢突触再生。为了做到这一点，我们使用了七鳃鳗脊髓的巨大网状脊髓（RS）神经元，因为它们易于再生，易于识别，并且包含作为脊椎动物兴奋性神经传递经典模型的大突触。利用光镜和电子显微镜相结合的方法，我们发现再生的巨突触在行为恢复几乎完全的时候恢复了对照巨突触的基本结构和突触前组织。然而，仍然存在一些明显的差异。最引人注目的是，再生的巨大RS轴突产生的突触很少。此外，再生轴突内的突触前位点比正常情况下更不复杂，具有更少的囊泡和更小的活动区。相比之下，突触前和停靠囊泡的密度几乎恢复到控制值。因此，即使再生突触结构稀疏且小，脊髓损伤后的功能恢复也可能发生，这表明功能恢复是由于整个脊髓网络中一系列更复杂的代偿变化。[j] .中国生物医学工程学报，2016,18(5):557 - 557。
Despite the potential importance that synapse regeneration plays in restoring neuronal function after spinal cord injury (SCI), even the most basic questions about the morphology of regenerated synapses remain unanswered. Therefore, we set out to gain a better understanding of central synapse regeneration by examining the number, distribution, molecular composition, and ultrastructure of regenerated synapses under conditions in which behavioral recovery from SCI was robust. To do so, we used the giant reticulospinal (RS) neurons of lamprey spinal cord because they readily regenerate, are easily identifiable, and contain large synapses that serve as a classic model for vertebrate excitatory neurotransmission. Using a combination of light and electron microscopy, we found that regenerated giant RS synapses regained the basic structures and presynaptic organization observed at control giant RS synapses at a time when behavioral recovery was nearly complete. However, several obvious differences remained. Most strikingly, regenerated giant RS axons produced very few synapses. In addition, presynaptic sites within regenerated axons were less complex, had fewer vesicles, and had smaller active zones than normal. In contrast, the densities of presynapses and docked vesicles were nearly restored to control values. Thus, robust functional recovery from SCI can occur even when the structures of regenerated synapses are sparse and small, suggesting that functional recovery is due to a more complex set of compensatory changes throughout the spinal network. J. Comp. Neurol. 518:2854–2872, 2010.