交感神经传出兴奋对大鼠慢性压迫背根节神经元放电的调节作用

Modulation of spontaneous activities in chronically compressed dorsal root ganglion neurons in rats by sympathetic efferent activation

目的 研究大鼠慢性压迫背根节 (dorsal root gan-glion,DRG)的交感 -感觉耦联现象 .方法 采用单纤维记录神经元自发放电的方法 ,在 DRG慢性压迫模型上 ,电刺激腰交感神经干 ,观察交感神经传出兴奋对受损 DRG神经元自发放电的调节作用 .结果 5 7%有自发放电的受损 DRG神经元对交感神经刺激有反应 ,其中反应类型有单纯兴奋、先兴奋后抑制和单纯抑制三种形式 ,反应的幅度随交感刺激持续时间的延长而逐渐增大 ,受损 DRG神经元对交感刺激的这种反应可被静脉注射 α受体阻断剂 -酚妥拉明所阻断 . 5 3%的受损DRG神经元对外源性去甲肾上腺素有元反应 ,其反应形式与交感刺激引起的反应类似 .结论 在慢性压迫 DRG神经元上存在交感 -感觉耦联现象 ,交感神经节后纤维末梢通过释放去甲肾上腺素 ,作用于受损 DRG神经元的

AIM To study sympathetic sensory coupling in chronically compressed dorsal root ganglion (DRG) in rats. METHODS In chronically compressed DRG model, the spontaneous activity of single fiber from DRG neuron was recorded, and lumbar sympathetic trunk electrically stimulated to study the sympathetic modulation of spontaneous activi ties in injured DRG neurons. RESULTS Fifty seven percent of spontaneous active neurons of injured DRG responded to sympathetic stimulation. The responses included simple excitation, excitation followed by inhibition and simple inhibition. Which enhanced with the increase of sympathetic stimulation time, and could be blocked by intravenously injection of phentolamine,α adrenorecepor antagonist. Fifty three percent of injured DRG responded to norepinephrine (NE). The responses to NE were similar to those induced by sympathetic stimulation. CONCLUSION Sympathetic sensory coupling is virtually present in chronically compressed DRG neurons. NE released from sympathetic nerve terminals acts on α adrenorecepor to influence spontaneous activities of injured DRG neurons.