摘要
目的:研究钩藤碱对急性分离的Wistar大鼠大脑皮层神经元低氧状态下L型钙通道的作用。方法:细胞贴附膜片钳技术,从-40mV去极化至0mV激活L型钙通道。结果:低氧可激活皮层神经元L型钙通道开放,使平均开放时间延长,平均关闭时间缩短,开放概率增加。钩藤碱(15和30μmol·L-1)可浓度依赖性抑制低氧状态下此钙通道的激活,缩短其平均开放时间(从887ms缩至303ms和223ms,P<0001),延长其平均关闭时间(从923ms延至3884和5443ms,P<0001)并降低其开放概率(从0142降至0031和0025,P<0001)此作用与维拉帕米(15μmol·L-1)相似,但稍弱。结论:钩藤碱对低氧大鼠大脑皮层神经元L型钙通道有阻滞作用,从而降低细胞内钙超载。
Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp technique. L type calcium channel was activated by stepping from 40 mV to 0 mV. Results: The results showed that the L type calcium channels of cortical neurons were activated by acute hypoxia. The mean open time of the channel was increased, the mean close time decreased and the open state probability raised during acute hypoxia. Rhy (15 and 30μmol·L -1 ) in concentration dependent manner blocked activity of the channels. The drug shortened the mean open time of the channels from 8 87 ms to 3 03 ms and 2 23 ms ( P <0 001), prolonged the mean close time from 9 23 ms to 38 84 ms and 54 43 ms ( P <0 001), and decreased the open state probability from 0 142 to 0 031 and 0 025 ( P <0 001) under the hypoxia condition, respectively. The effects of Rhy were similar to but weaker than those of verapamil (15 μmol·L -1 ). Conclusion: The study confirmed that Rhy has the blockade effects on L type calcium channels in cortical neurons of rats during hypoxia, by which it protects the brain from hypoxic injury.
关键词
膜片钳
皮层神经元
钙通道
钩藤碱
低氧
Patch clamp
Cortical neuron
Calcium
Ion channel
Rhynchophylline
Hypoxia