冬虫夏草水提液对单个心室肌细胞钾通道的影响

目的　观察冬虫夏草水提液对豚鼠及大鼠心室肌细胞钾通道的作用 ,探讨冬虫夏草的抗心律失常作用机制。方法　应用全细胞膜片钳技术记录冬虫夏草水提物对豚鼠单个心室肌细胞内向整流钾电流 (IK1)、延迟整流钾电流 (IK)及大鼠心室肌细胞瞬时外向钾电流 (Ito)的影响。结果　应用 0 1g·L-1(生药浓度 )冬虫夏草水提液使豚鼠单个心室肌细胞内向整流钾电流在实验电压 - 12 0mV时从给药前(- 36 37± 5 15 ) pA/pF减少到 (- 2 9 70± 5 90 ) pA/ pF(n=5 ,P <0 0 5 ) ;延迟整流钾电流在实验电压 +70mV时 ,从给药前 (9 2 1± 2 4 2 ) pA/ pF增加至 (11 5 4± 2 98)pA/ pF(n =6 ,P <0 0 1) ;使大鼠心室肌细胞瞬时外向钾电流 (Ito)在实验电压 +5 0mV时 ,从给药前 (13 36± 0 88) pA/ pF增加至 (16 4 8± 1 0 9) (n =4 ,P <0 0 1)。结论　冬虫夏草抗心律失常作用与它对心肌细胞钾通道的作用有关。它增加IK,Ito的同时抑制IK1,将会使动作电位时程缩短而不至于发生早后除极和迟后除极

Effects of water extracts from codyceps sinensis on potassium current in solatated ventricular cells

AIM To investigate the antiarrhythmic mechanism of water extract from codyceps sinensis(CS) on transmembrane potassium currents in single ventricular myocyte of guinea pig and rat. METHODS Whole-cell patch-clamp was used to record inward rectifier K + current(I K1),delayed rectifier K + current (I K) and transient outward K + current (I to) in single ventricular myocyte of guinea pig and rat. RESULTS In ventricular myocytes of guinea pig, I K1 was decreased from (-36.37±5.15) pA/pF to (-29.70±5.90) pA/pF(n=5, P<0.05) following CS 0.1 g·L -1 at -120 mV; I k increased from (9.21±2.42) pA/pF to (11.54±2.98) pA/pF (n=6, P<0.01)at +70 mV. In rat, I to was increased from (13.36±0.88) pA/pF to (16.48±1.09)(n=4,P<0.01). CONCLUSION The antiarrythmic effects of codyceps sinensis may be related to potassium current. It increased I K and I to, decreased I K1, resulting in APD decrease without early and delayed afterdepolarization.