Polgár Erika, Thomson Suzanne, Maxwell David J, Al-Khater Khulood, Todd Andrew J
Spinal Cord Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
Eur J Neurosci. 2007 Sep;26(6):1587-98. doi: 10.1111/j.1460-9568.2007.05793.x.
The dorsal horn of the rat spinal cord contains a population of large neurons with cell bodies in laminae III or IV, that express the neurokinin 1 receptor (NK1r) and have long dorsal dendrites that branch extensively within the superficial laminae. In this study, we have identified a separate population of neurons that have similar dendritic morphology, but lack the NK1r. These cells also differ from the NK1r-expressing neurons in that they have significantly fewer contacts from substance P-containing axons and are not retrogradely labelled following injection of tracer into the caudal ventrolateral medulla. We also provide evidence that these cells do not belong to the postsynaptic dorsal column pathway or the spinothalamic tract. It is therefore likely that these cells do not have supraspinal projections. They may provide a route through which information transmitted by C fibres that lack neuropeptides is conveyed to deeper laminae. The present findings demonstrate the need for caution when attempting to classify neurons solely on the basis of somatodendritic morphology.
大鼠脊髓背角包含一群大神经元，其细胞体位于板层III或IV，表达神经激肽1受体（NK1r），并具有长的背侧树突，这些树突在浅表板层内广泛分支。在本研究中，我们鉴定出了另一群神经元，它们具有相似的树突形态，但缺乏NK1r。这些细胞也与表达NK1r的神经元不同，因为它们与含P物质的轴突的接触明显较少，并且在将示踪剂注入尾侧腹外侧延髓后不会被逆行标记。我们还提供证据表明这些细胞不属于突触后背柱通路或脊髓丘脑束。因此，这些细胞很可能没有脊髓上的投射。它们可能提供了一条途径，通过该途径，缺乏神经肽的C纤维传递的信息被传递到更深的板层。目前的研究结果表明，仅根据体树突形态对神经元进行分类时需要谨慎。
