A型肉毒毒素对大鼠受损背根节神经元放电和交感-感觉耦联的影响

目的 研究A型肉毒毒素(BTXA)对慢性压迫背根节(DRG)神经元(慢性神经痛模型)的自发放电和交感-感觉耦联的影响.方法 采用单纤维记录神经元自发放电的方法,在受损DRG上加BTXA,观察BTXA对DRG神经元自发放电的影响.电刺激腰交感神经干,观察交感刺激对受损DRG神经元放电的调节作用,静脉注射BTXA后,再观察交感刺激对受损DRG神经元放电的影响.结果 慢性压迫DRG神经元有丰富的自发放电,47个受损DRG神经元放电对无钙人工脑脊液有显著的兴奋反应,但BTXA对这些神经元的自发放电无影响.64%的受损DRG神经元对腰交感神经干电刺激有反应,交感刺激对受损DRG的这种作用可被静脉注射BTXA所阻断.结论 BTXA对慢性压迫DRG神经元的自发放电无影响.在慢性压迫DRG神经元上存在交感-感觉耦联现象,BTXA可以阻断这种交感-感觉耦联现象.

Botulinum toxin type A does not affect spontaneous discharge but blocks sympathetic-sensory coupling in chronically compressed rat dorsal root ganglion neurons

Objective To study the effect of botulinum toxin type A(BTXA) on spontaneous discharge and sympathetic-sensory coupling in chronically compressed dorsal root ganglion(DRG) neurons in rats.Methods In chronically compressed rat DRG,spontaneous activities of the single fibers from DRG neurons were recorded and their changes observed after BTAX application on the damaged DGR.Sympathetic modulation of the spontaneous discharge from the compressed DRG neurons was observed by electric stimulation of the lumbar sympathetic trunk,and the changes in this effect were evaluated after intravenous BTXA injection in the rats.Results Active spontaneous discharges were recorded in the injured DRG neurons,and 47 injured DRG neurons responded to Ca2 -free artificial cerebrospinal fluid but not to BTXA treatment.Sixty-four percent of the neurons in the injured DRG responded to sympathetic stimulation,and this response was blocked by intravenously injection of BTXA.Conclusion BTXA does not affect spontaneous activities of injured DRG neurons,but blocks sympathetic-sensory coupling in these neurons.