Study on changes in the projection manner of myelinated fibers following transection of the trigeminal nerve.

用组织化学方法研究了大鼠眶下神经和舌神经的有髓初级传入纤维向三叉神经核复合体的投射方式。这些有髓纤维终止于感觉主核、口侧核、间侧核和尾侧核的I、V板层。切断眶下神经后1周，有髓纤维在三叉神经尾侧核的投射方式发生改变。虽然有髓纤维基本不终止于幼年大鼠的II板层，但在板层II观察到了这种有髓纤维的新投射，这表明初级传入切断会导致中枢神经系统神经可塑性的变化。为了阐明神经切断后神经可塑性的机制，1999-2000年间，通过切断初级传入，研究了转录因子c-Fos和ZIF/268的表达。Expressi…切断和暴露三叉神经尾侧核中的眶下神经可诱导更多的转录因子表达，但两种处理后在该核内表达这些蛋白的区域非常相似，这表明很难根据眶下神经的切断或暴露来区分表达这些蛋白的神经元。另一方面，切断坐骨神经可使这些蛋白在腰髓第4和第5层的背角I/II层表达，而暴露该神经诱导的这些蛋白仅限于该层的外侧1/3。神经切断后在该板层外侧1/3处表达的神经元数量与暴露该神经后的神经元数目非常相似，表明坐骨神经切断后在该区域诱导的这些蛋白的表达来自于该神经的暴露，而在该板层的内侧2/3处的这些蛋白的表达来自于神经切断。这一结果表明，能够研究神经切断诱导这些蛋白表达的机制。首先，研究谷氨酸受体拮抗剂对坐骨神经切断后这些蛋白表达的影响。这些蛋白在神经切断后的板层中的表达被抑制，但作用仅限于外侧1/3，而在该区域的内侧2/3处则无影响，提示神经暴露后的组织损伤与神经切断后组织损伤的谷氨酸受体的参与可能有相当大的差异。较少

The projection manner of myelinated primary affferents, the rat infraorbital nerve and lingual nerve, into the trigeminal nuclear complex was investigated histochemically at 1998. These myelinated fibers terminated in the main sensory nucleus, nucleus oralis, nucleus interporalis and the lamina I and laminae III-V of the nucleus caudalis. After the infraorbital nerve was transected, the projection fashion of myelinated fibers was changed in the trigeminal nucleus caudalis one week after this treatment. Although myelinated fibers do not terminate basically in lamina II of naive rats, a new projection of this myelinated fiber was observed in lamina II, suggesting that transection of primary afferents produces changes in neural plasticity in the central nervous system.To clarify the mechanisms involved in neural plasticity after nerve transection, the expression of transcription factors, c-Fos and Zif/268, was investigated by transection of primary afferents during 1999-2000. The expressi … More on of these transcription factors was induced by both transection and exposure of the infraorbital nerve in the trigeminal nucleus caudalis, but the region expressing these proteins following the two treatments was closely similar to each other in this nucleus, indicating that it is difficult to distinguish neurons expressing these proteins according to transection or exposure of the infraorbital nerve. On the other hand, transection of the sciatic nerve produced the expression of these proteins throughout laminae I/II of the dorsal horn at the 4 and 5th levels of the lumbar spinal cord, while the induction of these proteins by exposure of this nerve was restricted in the lateral one third of this lamina. The number of neurons expressed in this lateral one third of this lamina after nerve transection was closely similar to that derived from exposure of this nerve, indicating that the expression of these proteins induced in this region following transection of the sciatic nerve is derived from exposure of this nerve, while the expression of these proteins at the medial two third of this lamina is derived from nerve transection. This result suggested that it is able to investigate the mechanisms involved in the expression of these proteins induced by nerve transection. First, the effects of pretreatment with glutamate receptor antagonists on the expression of these proteins following transection of the sciatic nerve were investigated. The expression of these proteins in this lamina following nerve transection was reduced by this preteatment, but the effects were restricted in the lateral one third of this lamima whereas no effect was found in the medial two third of this region, suggesting that there may be considerable differences in the involvement of glutamate receptors between tissue injury following nerve exposure and nerve transection. Less