电压依赖性钙通道参与大振幅微小兴奋性突触后电流形成的实验研究  

Voltage-dependent Calcium Channel Plays a Role in the Formation of Large-amplitude Miniature Excitatory Postsynaptic Current

作　　者：黄福森[1] 杨小娟[1] 王儒蓉[1] 吴超然[1] 

机构地区：[1]四川大学华西医院麻醉科,成都610041

出　　处：《华西医学》2012年第6期905-909,共5页West China Medical Journal

摘　　要：目的观察电压依赖性钙通道是否作用于大鼠脊髓背角胶状质层(SG)神经元大振幅微小兴奋性突触后电流的形成。方法选用成年雄性Sprague-Dawley(SD)大鼠,2%～3%异氟烷麻醉后,分离其腰骶部的脊髓,然后切片。采用全细胞电压钳技术,玻璃微电极的电阻为4～6 MΩ,钳制电压为70 mV,记录胶状质层神经元微小兴奋性突触后电流(mEPSC)电流。将电流信号用Axopatch 200来放大并储存于电脑。对照组和用药结束后,持续采样mEPSC电流30 s。mEPSC电流的频率和振幅用Clampfit 8.1进行分析。结果钳制电压为70 mV时,所有SG神经元均有自发性的EPSC。辣椒素增加mEPSC发生的频率和波幅。钴离子抑制辣椒素诱导的大振幅mEPSC。钴离子抑制辣椒素诱导的mEPSC的平均振幅,而不抑制其发生频率。结论电压依赖性钙离子通道参与了辣椒素引起的痛觉形成。Objective To observe whether the voltage-dependent calcium channel contributes to the formation of capsaicin-induced miniature excitatory postsynaptic current （mEPSC） in rats. Methods Experiments were performed in adult male Sprague-Dawley rats. The lumbosacral portion of the spinal cord were separated after anesthesia by 2%- 3% isoflurane, and the spinal cord slices were prepared. Whole-cell voltage-clamp technique was applied to substantia gelatinosa （SG） neurons with a glass patch-pipette having a resistance of 4-6 MΩ, holding potential -70 mV. Signals were amplified with an Axopatch 200 amplifier and then stored in a personal computer. The mEPSC in controls and immediately after the end of drug applications were sampled for 30 seconds and the frequency and amplitude were analyzed using Clampfit 8.1. Results All SG neurons in this database had spontaneous mEPSC with the holding potential of-70 mV. Capsaicin increased the frequency and mean amplitude of mEPSC. Cobalt inhibited the capsaicin-induced large-amplitude mEPSC, as well as the mean amplitude but not the frequency of the capsaicin-induced mEPSC. Conclusion Voltagedependent calcium channel may contribute to the generation of capsaicin-induced pain sensation.

关 键 词：辣椒素 电压依赖性钙通道 微小兴奋性突触后电流 大鼠 

分 类 号：R614[医药卫生—麻醉学]