BK8644对河豚毒素引起的大鼠海马锥体神经元AMPA受体介导的微小兴奋性突触后电流频率和幅度的影响

目的观察L-型钙通道(LTC)开通剂BK8644对河豚毒素(TTX)引起的大鼠海马锥体神经元α-氨基-羟基-5-甲基-4-异唑-丙酸(AMPA)受体介导的微小兴奋性突触后电流(mEPSCAMPA)的影响,探讨LTC是否作为神经环路兴奋性的感受器在调节突触稳态中发挥作用。方法建立培养海马神经元的稳态可塑性离体模型,并采用膜片钳全细胞模式记录突触内自发的mEPSC。结果TTX组mEPSCAMPA的频率显著高于对照组(P<0.05),而mEPSCAMPA电流幅度无显著差异(P>0.05);BK8644组和TTX+BK8644组与对照组比较,mEPSCAMPA的频率和幅度均无显著差异(P>0.05);TTX+BK8644组与TTX组比较,mEPSCAMPA频率降低(P<0.05),电流幅度无显著差异(P>0.05)。结论BK8644可对抗TTX引起的mEPSCAMPA频率升高,提示L-型钙通道可能参与稳态突触可塑性的调节。

Effect of BK8644 on frequency and amplitude of mEPSCAMPA induced by tetraodontoxin in cultured hippocampal pyramidal neurons of rats

Objective To examine the effects of the L-type calcium channel agonist BK8644 on the mEPSCAMPA induced by tetraodontoxin(TTX) in cultured hippocampal pyramidal neurons of rats,and to explore the roles of L-type calcium channel in the regulation of homeostatic synaptic plasticity.Methods The model of homeostatic synaptic plasticity of cultured hippocampal pyramidal neurons was established,and the synaptic mEPSC was recorded by Whole-cell patch-clamp recordings.Results The frequence of mEPSCAMPA was higher in TTX group than this in control group(P<0.05),but there was no significant difference in the amplitude of mEPSCAMPA between two groups(P>0.05).There was no significant difference in the frequence and amplitude of mEPSCAMPA among BK8644 group,TTX BK8644 group and control group(P>0.05).The frequence of mEPSCAMPA was lower in TTX BK8644 group than that in TTX group(P<0.05),but there was no significant difference in the amplitude of mEPSCAMPA between two groups(P>0.05).Conclusion BK8644 can prevent the increase of the frequence of mEPSCAMPA induced by TTX,it suggest that the L-type calcium channel may be involved in the regulation of homeostatic synaptic plasticity.