中文摘要：

目的研究辣椒素对大鼠背根神经节神经元的电压门控性钙离子通道的抑制效应及其信号机制。方法在急性分离的大鼠背根神经节（DRG）神经元上，应用全细胞膜片钳技术记录电压激活性钙离子通道电流以及辣椒素诱导的电流，应用钙离子成像技术检测Ca^2＋浓度的变化。结果辣椒素能够抑制大鼠DRG神经元的电压激活性钙离子通道电流。细胞外钾离子浓度显著升高引起细胞去极化并打开膜上电压门控性钙离子通道引起胞外Ca^2＋内流，辣椒素只在引起胞内Ca^2＋浓度显著升高的情况下才能抑制高钾诱导的电压门控性Ca^2＋内流。用咖啡因耗竭细胞内Ryanodine敏感性钙库以后，辣椒素引发的胞内钙浓度升高的效应被显著抑制，说明辣椒素可诱导胞内Ryanodine敏感性钙库释放Ca^2＋。结论在辣椒素敏感性的大鼠DRG神经元中，辣椒素通过胞内钙信号抑制电压门控性钙离子通道。Ca^2＋信号部分来源于Ryanodine敏感性钙库。

英文摘要：

Objective To investigate the inhibitory effect of capsaicin on voltage-activated calcium channels and its signaling mechanisms in rat dorsal root ganglion （DRG） neurons. Methods Acutely isolated DRG neurons were used . Voltage - activated calcium channel currents and capsaicin - induced currents were recorded by patch clamp technique. Calcium imaging technique was applied to monitor the change of intracellular Ca2 ＋ concentration. Results In this study, we demonstrated that capsaicin could inhibit voltage-activated calcium channel currents in rat dorsal root ganglion neurons. Voltage-gated Ca2＋ influx via K ＋ -dependent depolarization was profoundly inhibited by capsaicin in neurons where capsaicin significantly increased intracellular Ca2＋concentration. Furthermore, the capsaicin-induced intracellular Ca2＋ concentration enhancement could be profoundly oppressed after depleting ryanodine-sensitive Ca2＋ store by caffeine, which indicated that capsaicin could mobilize Ca2＋ from ryanodine-sensitive Ca2＋ stores. Conclusion The inhibitory effect of capsaicin on voltage-activated calcium channels in capsaicin-sen- sitive dorsal root ganglion neurons is via intracellular Ca2＋ which partly source from ryanodine-sensitive Ca2＋ stores.