P物质对大鼠三叉神经节神经元辣椒素激活电流的调制作用

Modulation of Capsaicin-activated Current by SP in Rat TG Neurons

目的研究P物质(SP)对急性分离的大鼠三叉神经节神经元辣椒素受体亚型1(VR1)的调制作用,探讨SP对辣椒素在疼痛传导中作用的影响。方法采用全细胞膜片钳技术记录急性分离的三叉神经节神经元膜VR1介导的电流,并观察预加SP对VR1介导的电流的调制作用。结果大多数三叉神经节细胞对辣椒素敏感,细胞外应用辣椒素(1×10-7~3×10-6mol/L)后可引起缓慢激活无明显去敏感的内向电流,且呈浓度依赖性;分别预加1×10-9、3×10-9和1×10-8mol/L SP 1 min后,辣椒素引起的电流幅值分别增加2.4%、20.8%和51.8%,增加的程度与SP的浓度和预加的持续时间有关。应用SP受体特异性阻断剂GR82334(1×10-6mol/L)可以阻断SP对辣椒素激活电流的增强作用。结论SP可增强三叉神经节神经元膜辣椒素受体介导的电流。

Objective To investigate the modulatory effects of substance P(SP) on capsaicin-activated current and the pain pathway mediated by capsaicin.Methods Whole-cell patch clamp technique was used to record the capsaicin-activated current in freshly isolated rat trigeminal ganglion(TG) neurons, and the effects of SP pretreatment were investigated.Results The majority of TG neurons examined(46/58) responded to capsaicin with an inward current in a dose-dependent(1×10^(-7)-3×10^(-6)mol/L) manner.Pretreatment of SP(1×10^(-9),3×10^(-9),1×10^(-8)mol/L) potentiated the capsaicin-activated current concentration-and time-dependently.GR82334(1×10^(-6) mol/L),blocker of SP receptor,could abolish the potentiation of SP.Conclusion SP can potentiate capsaicin-activated current in rat TG neurons.