Expression of tyrosine kinase receptor C in the segments of the spinal cord and the cerebral cortex after cord transection in adult rats

To investigate the role of tyrosine kinase receptor C (TrkC), the receptor of neurotrophin-3 (NT-3), in neuroplasticity following spinal cord injury (SCI).Rats with cord transection were allowed to survive for 1, 3, 7 and 14 d post operation (dpo). TrkC expressions at lower thoracic levels of the spinal cord and in precentral gyrus of cerebral cortex were investigated.TrkC protein levels at both the site of injury (T10-T11) and the neighboring segments (T9 and T12) in the spinal cord decreased significantly at 1-7 dpo, followed by a rapid increase at 14 dpo. The temporal changes in TrkC mRNA expression level showed a similar pattern with that of TrkC protein. In addition, the levels of TrkC protein and mRNA at the site of injury (T10-T11) were significantly higher than those at the neighboring spinal segments (T9 and T12). Besides, the levels of TrkC protein and mRNA were higher at the rostral segment than at the caudal segment. However, in the motor cortex, TrkC protein was not detected and TrkC mRNA was expressed at a very low level.These results suggest that TrkC may be involved in neuroplasticity after SCI.