三叉神经节细胞电压门控通道研究中的钙电流振荡活动

目的 :探讨三叉神经节细胞电压门控性钙通道电流特性。方法 :在急性分离的三叉神经节细胞膜上 ,阻断电压门控性延迟整流钾通道和电压门控性钠通道 ,在 - 70mV的钳制电位下 ,给予 1 0mV步幅递增、80ms步宽的去极化脉冲刺激 ,进行全细胞膜片钳记录。结果 :在仅阻断电压门控性延迟整流钾通道时 ,- 1 0mV的去极化脉冲刺激激活了三叉神经节细胞膜上继快钠电流之后的慢内向电流 ,呈重复开闭的振荡特性 ;同时阻断电压门控性延迟整流钾通道和电压门控性钠通道 ,在 - 2 0mV的去极化脉冲刺下 ,也可记录到呈振荡特性的慢内向电流。振荡电流可被细胞外喷射的 1mmol·L-1 尼福地平所阻断。结论 :三叉神经节细胞膜上高电压激活的重复开闭慢内向电流可能为电压门控性钙电流 ,其振荡特性可能与感觉信息中枢传入的初级加工有关。

The Oscillation of Voltage-Gated Calcium Currents in Trigeminal Root Ganglion Neurons

Objective: To study the characteristics of voltage gated calcium currents in trigeminal root ganglion neurons. Methods: Whole cell patch clamp recording were performed in acutely isolated mice trigeminal root ganglion neurons under the condition of inhibiting voltage gated potassium currents and sodium currents. Results: Slow inward currents were elicited in response to a series of depolarizing pulses from membrane holding potential of -70 mV to +60 mV by step of 10 mV. These oscillatory slow inward currents which inhibited by 1 mmol·L -1 nifedipine took on the characteristics of repetitive opening and closing. Conclusion: These slow inward currents elicited by high voltage might be the calcium currents and might relate to proceeding sensory information for its repetitive opening and closing.