PTD-BDNF对海马神经元钠、钾、钙离子通道的影响

目的研究PTD-BDNF对大鼠海马神经元细胞钠、钾、钙离子通道的影响。方法全细胞膜片钳技术记录海马神经元细胞电压依赖性钠、钾、钙通道电流,观察并分析PTD-BDNF对离子通道电流的影响。结果与对照组比较,PTD-BDNF、BDNF使海马神经元钠通道电流强度峰值分别增加39.35%和41.99%（n=4,P〈0.01）;使钠通道电流-电压关系曲线下移（n=4,P〈0.01）;使海马神经元钙通道电流强度峰值分别增加39.20%和38.72%（n=4,P〈0.01）;使钙通道电流-电压关系曲线下移（n=4,P〈0.01）;使海马神经元钾通道电流IA、IK在20mv刺激处分别比对照组降低29.03%、28.06%和29.76%、33.38%;使钾电流-电压关系曲线下移（n=4,P〈0.01）。PTD-BDNF与BDNF两者之间比较差异均无统计学意义（P〉0.05）。结论PTD-BDNF显示了与脑源性神经营养因子相似的电压依赖性离子通道的调节作用,说明PTD-BDNF与脑源性神经营养因子在调节神经元静息膜电位、神经兴奋性方面有相同的分子基础。

Effect of protein transduction domain-brain derived neurotrophic factor on Na+,Ca2+,K+ channels of hippocampal neurons

Objective To study the effects of protein transduction domain （PTD）-brain derived neurotrophic factor （BDNF） on Na^＋ , Ca^2＋ , and K ^＋ channels on rat hippocampus neurons. Methods Voltage-dependent currents of Na ^＋ , Ca^2＋ , and K^＋ channels in cultured rat hippoeampal neurons were recorded using the whole-cell patch-clamp technique. Effect of PTD-BDNF on the current of Na ^＋ , Ca^2＋ , and K ^＋ channels was observed. Results Compared with the control group, the peak amplitude of PTD-BDNF and BDNF increased 39.35% and 41.99% , respectively, making the curve of Na^＋ current sweep down（ n = 4, P 〈 0. 01 ）. The peak amplitude of hippoeampus neurons increased 39. 20% and 38. 72% , respectively, making the curve of Ca^2＋ current sweep down （ n = 4, P 〈0.01）. Compared with the control group, at the stimulant voltage of 20mV, the peak amplitude of PTD-BDNF and BDNF decreased 29.30% , 28.06% and 29.76% , 33.38% , making curve of K ^＋ current sweep down（ n = 4, P 〈 0. 01 ）. There was no difference in effect of PTD-BDNF and BDNF, P 〉 0.05. Conclusion PTD-BDNF and BDNF have similar modulation effects on vohage-dependent ion channels, and share a similar molecular basis in resting membrane potential of neurons and nervous excitation.