孤啡肽对大鼠顶叶皮层神经元瞬时外向钾电流的抑制作用

目的：研究孤啡肽（N／OFQ）对大鼠顶叶皮层神经元瞬时外向钾电流（IA）的影响,初步探讨其作用的通道动力学机制。方法：采用全细胞膜片钳技术,观察N／OFQ对急性分离的大鼠顶叶皮层神经元IA的作用。结果：①0．1μmol／L N／OFQ使IA幅值由给药前的（5356．1±361．6）pA下降为（4113．3±312．7）pA,抑制率为23．20％±2．17％（P〈0．01,n=10）。②0．1μmol／L N／OFQ使IA的电流-电压（I-V）曲线降低（P〈0．01,n=10）。③0．1μmol／L N／OFQ使,IA激活曲线的半数激活电压（V1／2）和斜率因子（κ）分别由给药前的（-9．2±2．5）mV和（20．4±2．3）mV变为给药后的（30．6±3．7）mV（P〈0．01,n=8）和（22．6±2．1）mV（P〉0．05,n=8）。④0．1μmol／L N／OFQ使IA失活曲线的半数失活电压（V1／2）和斜率因子（κ）分别由给药前的（-64．1±3．2）mV和（21．5±2．1）mV变为给药后的（-55．9±1．9）mV（P〈0．05,n=5）和（19．6±2．2）mV（P〉0．05,n=5）。结论：N／OFQ可抑制大鼠顶叶皮层神经元IA,使其激活曲线、失活曲线均右移。

Inhibition of N/OFQ on transient outward potassium currents in acutely dissociated rat cerebral parietal cortical neurons

Aim： To study the effect of Nociceptin/orphanin FQ （ N/OFQ ） on transient outward potassium（IA） in rat cerebral cortical neurons and its kinetic mechanism. Methods： The effects of N/OFQ on IA were investigated by using the whole cell patch clamp technique in acutely dissociated rat cerebral cortical neurons. Results： ①At the voltage of ＋ 60 mV, 0.1 μmol/L N/OFQ made IA decreased from （5356.1 ± 361.6）pA to （4113.3 ±312.7） pA （P 〈 0.01, n = 10） and the percent inhibition was 23.2% ±2.2 %. ②N/OFQ made IV curve of IA decreased significantly （ P 〈 0.01, n = 10）. ③0.1μmol/L N/OFQ shifted the activation curve of IA to positive potential from （-9.2 ± 2.5） mV to （30.6 ±3.7 ） mV （ P 〈 0.01, n = 8） and changed the slope factor（ κ ） of the activation curve from （20.4 ±2.3） mV to （22.6 ±2.1 ） mV （ P 〉 0.05, n = 8）. ④0.1 μmol/L N/OFQ caused a significant hyperpolarizing shift of the inactivation curve from （-64.1 ± 3.2） mV to （-55.9 ±1.9） mV（ P 〈 0.05, n = 5）, without significant effect on κ of the inactivation curve. Conclusion： 0.1 μmol/L N/OFQ has a significant inhibition on IA and shift the activation and inactivation curve to depolarization in cerebral parietal cortical neurons of rats.