Anatomical and Molecular Properties of Long Descending Propriospinal Neurons in Mice.
Anatomical and Molecular Properties of Long Descending Propriospinal Neurons in Mice.
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DOI：
10.3389/fnana.2017.00005
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发表时间：
2017
影响因子：
2.9
通讯作者：
Graham BA
中科院分区：
文献类型：
--
作者：
Flynn JR;Conn VL;Boyle KA;Hughes DI;Watanabe M;Velasquez T;Goulding MD;Callister RJ;Graham BA
长下行固有脊髓神经元(LDPN)是在颈椎和腰椎脊髓环路之间形成直接连接的中间神经元。低密度脂蛋白参与肢体间的协调，是脊髓损伤后功能恢复的重要介质。我们对LDPN的了解大多来自一系列物种，然而，越来越多的转基因小鼠品系被用来更好地定义神经元种群，这就要求对LDPns在小鼠中的特征进行更完整的描述。在这项研究中，我们研究了小鼠LDPN的胞体位置、抑制性神经递质表型、发育来源、形态和突触传入整个颈和上胸脊髓。从腰髓逆行标记LDPN，以绘制整个颈段和上胸段的细胞体位置。同侧LDPN分布于背、中、腹侧灰质以及脊髓外侧核和颈外侧核。相反，对侧LDPN更密集地集中在腹内侧灰质。GlyT2GFP和GAD67GFP小鼠的逆行标记显示，大多数抑制性LDPN投射到同侧或邻近中线。此外，我们使用了几个转基因小鼠品系来确定LDPns的发育来源，发现V2b阳性神经元形成了同侧投射LDPns的子集。最后，对一组神经生物素(NB)标记的LDPN进行了详细的评估，以检查形态并绘制出来自各种神经化学不同轴突终末的接触的空间分布。这些结果为进一步研究它们在脊髓损伤后的活动和恢复中的作用提供了重要的基线数据。
Long descending propriospinal neurons (LDPNs) are interneurons that form direct connections between cervical and lumbar spinal circuits. LDPNs are involved in interlimb coordination and are important mediators of functional recovery after spinal cord injury (SCI). Much of what we know about LDPNs comes from a range of species, however, the increased use of transgenic mouse lines to better define neuronal populations calls for a more complete characterisation of LDPNs in mice. In this study, we examined the cell body location, inhibitory neurotransmitter phenotype, developmental provenance, morphology and synaptic inputs of mouse LDPNs throughout the cervical and upper thoracic spinal cord. LDPNs were retrogradely labelled from the lumbar spinal cord to map cell body locations throughout the cervical and upper thoracic segments. Ipsilateral LDPNs were distributed throughout the dorsal, intermediate and ventral grey matter as well as the lateral spinal nucleus and lateral cervical nucleus. In contrast, contralateral LDPNs were more densely concentrated in the ventromedial grey matter. Retrograde labelling in GlyT2GFP and GAD67GFP mice showed the majority of inhibitory LDPNs project either ipsilaterally or adjacent to the midline. Additionally, we used several transgenic mouse lines to define the developmental provenance of LDPNs and found that V2b positive neurons form a subset of ipsilaterally projecting LDPNs. Finally, a population of Neurobiotin (NB) labelled LDPNs were assessed in detail to examine morphology and plot the spatial distribution of contacts from a variety of neurochemically distinct axon terminals. These results provide important baseline data in mice for future work on their role in locomotion and recovery from SCI.