Hagg T, Rende M, Magal E, Burnham P, Oudega M, Varon S
Department of Biology, University of California, San Diego 92093-0601.
Brain Res Bull. 1993;30(3-4):347-52. doi: 10.1016/0361-9230(93)90263-b.
Developing spinal motor neurons (SMN) express low-affinity nerve growth factor receptors (LNGFR) but not high-affinity transducing NGF receptors. Moreover, SMN are not supported by NGF in vitro. In the normal adult rat most SMN are not LNGFR immunoreactive (LNGFR-IR), but they transiently reexpress LNGFR (though not the high-affinity receptor) after peripheral nerve injury. With a cut lesion of the sciatic nerve (when only a neuroma forms), the number of LNGFR-IR SMN at L4-L6 rapidly increases to a maximum between day 1 and 7 and returns to baseline levels by day 30. After a crush lesion (accompanied by regeneration to the muscle), LNGFR-IR SMN appear in about the same numbers, but they start to disappear 1 week later. We speculate that the similar appearance and differential decline of LNGFR-IR seen after the two types of lesions are regulated by the availability of a common signal such as ciliary neurotrophic factor. The adult SMN model provides a good opportunity to investigate the reexpression of LNGFR after peripheral nerve injury, and more generally, the unknown role and regulation of LNGFR.
发育中的脊髓运动神经元（SMN）表达低亲和力神经生长因子受体（LNGFR），但不表达高亲和力的转导型NGF受体。此外，体外培养时SMN不受NGF支持。在正常成年大鼠中，大多数SMN无LNGFR免疫反应性（LNGFR-IR），但在周围神经损伤后它们会短暂地重新表达LNGFR（尽管不是高亲和力受体）。坐骨神经切断损伤（仅形成神经瘤时）后，L4-L6节段LNGFR-IR SMN的数量在第1天至第7天迅速增加至最大值，并在第30天恢复到基线水平。挤压损伤（伴有神经向肌肉再生）后，LNGFR-IR SMN数量大致相同，但1周后开始减少。我们推测，两种损伤后LNGFR-IR的相似出现和不同下降是由一种共同信号（如睫状神经营养因子）的可用性调节的。成年SMN模型为研究周围神经损伤后LNGFR的重新表达提供了一个很好的机会，更广泛地说，也为研究LNGFR未知的作用和调节机制提供了机会。
