吗啡对坐骨神经钳夹伤大鼠脊髓Ⅱ板层初级传入纤维终末突触重建的影响

EFFECTS OF MORPHINE ON SYNAPTIC RECONSTRUCTION OF PRIMARY AFFERENT FIBER TERMINAL AT SPINAL LAMINA Ⅱ FOLLOWING SCIATIC NERVE CRUSH IN RAT

目的 探讨吗啡能否促进大鼠受损伤的初级传入纤维终末在脊髓Ⅱ板层再生及其突触重建。 方法 采用电镜定量方法计数吗啡组、生理盐水组和纳络酮吗啡组坐骨神经损伤后 15d和 30d ,L4脊髓Ⅱ板层背根无髓传入纤维来源的Ⅰ型复合终末、背根有髓传入纤维来源的Ⅱ型复合终末和由中间神经元轴突和下行传导束轴突形成的简单终末。 结果 吗啡组大鼠脊髓Ⅱ板层的Ⅰ型复合终末数比生理盐水组和纳络酮吗啡组明显增多 ,然而 ,Ⅱ型复合终末却比生理盐水组和纳络酮吗啡组少。 3组大鼠脊髓Ⅱ板层的突触性终末总数 ,复合终末数和简单终末数没有差异。 结论 吗啡能够促进大鼠脊髓Ⅱ板层受损伤的初级无髓传入纤维终末再生及其突触重建 ,这可能通过阿片受体介导。

Objective To explore whether morphine could promote the regeneration and synaptic reconstruction of injured primary afferent fiber terminals at spinal lamina Ⅱ of rat. Methods The type Ⅰ complex terminals (CⅠ) of unmyelinated afferent fiber of dorsal root, the type Ⅱ complex terminals (CⅡ) of myelinated afferent fiber of dorsal root, and the simple terminals (ST) of interneuronal axon and descending tract axon at L4 spinal lamina Ⅱ were counted by an EM quantitative method 15d and 30d after sciatic nerve injured in morphine, vehicle and naloxone and morphine groups of rat. Results Compared with vehicle and naloxone and morphine groups, the CⅠ number increased apparently in morphine group.However, the CⅡ number in morphine group decreased more than in vehicle and naloxone and morphine groups. There was no difference significantly in number of all synaptic terminals, number of complex terminals and number of simple terminals at L4 spinal lamina Ⅱ among 3 groups. Conclusion Morphine may promote the regeneration and synaptic reconstruction of the terminals of injured primary unmyelinated afferent fiber at spinal lamina Ⅱ, which might be mediated by opioid μ recepter.