【摘要】 目的:研究滇黄芩总黄酮(totla flavonoid)对豚鼠心肌组织电压门控性钠通道的影响。方法:成年豚鼠,肝素抗凝后,腹腔麻醉,断头处死,迅速取其心脏,进行Langendorff灌流,先用无钙台式液灌流10 min,再以Ⅰ型胶原酶溶液灌流心脏,待心脏基本变软后剪取心室部分,制备单个心室肌细胞。分离出的豚鼠心肌单细胞,用全细胞电压钳技术记录电压依赖性钠电流进行研究。结果:滇黄芩总黄酮能可逆性抑制钠电流,其半数抑制浓度(IC50)为106 mg.L-1(95%的可信限是92～112 mg.L-1)。滇黄芩总黄酮并不影响钠通道激活开放的刺激电位阈值、最大激活电位值和反转电位值,但能使可激活开放的钠通道明显减少,钠离子电流明显衰减,可引出的钠电流在-40 mV处较正常组减少45.6%。细胞外给予滇黄芩总黄酮不影响钠通道激活曲线:对照组与106 mg.L-1的滇黄芩总黄酮组的半激活电压(V1/2)分别为(-50.4±1.7)mV和(-50.1±3.1)mV(n=6差异无统计学意义)。细胞外给予滇黄芩总黄酮可影响钠通道失活曲线,106 mg.L-1的滇黄芩总黄酮对电压依赖性稳态失活钠电流会引起一个大约12 mV的负向漂移,延缓失活钠通道的恢复:对照组与106 mg.L-1的滇黄芩总黄酮组的V1/2分别为(-69.4±1.6)mV和(-79.3±3.2)mV(n=7,P<0.05),两者间的差异有显著性意义,斜率分别为(-8.2±0.9)mV和(7.1±0.7)mV。细胞外给予滇黄芩总黄酮也可影响失活钠通道的恢复,使钠通道的复活时间常数显著延长:对照组和106mg.L-1的滇黄芩总黄酮组的时间常数分别为(15.6±6.3),(29.8±14.8)ms(n=6,P<0.05),差异有显著性意义。结论:滇黄芩总黄酮可阻滞豚鼠心肌细胞钠通道,是稳定的豚鼠心肌组织钠通道阻断剂。更多还原

【Abstract】 Objective:To study the effects of total flavonoid from Scutellaria amoena on voltage-gated Na+ channels in cardiac tissues.Method:Adult guinea-pigs were heparinized and then sacrificed by decapitation after being anesthetized.The heart was removed immediately,and the aorta of the isolated heart was connected to a Langendorff apparatus and perfused with Ca2+-free Tyrode’s solution for 10 min,and then with the same solution containing collagenase I.After dissociation and collection,cells were mechanically dispersed and single ventricular myocytes were enzymatically dissociated from adult guinea-pig heart.Voltage-dependent Na+ current was recorded using whole cell voltage-clamp technique.Result:Total flavonoid reversibly inhibited Na+ current with an IC50 value of 106 mg·L-1(95%confidence range:92-112 mg·L-1).The inhibitory effects of total flavonoid on Na+ current exhibited use-dependence.Total flavonoid at 106 mg·L-1 caused a negative shift(about 12 mV)in the voltage-dependence of steady-state inactivation of Na+ current,and retarded its recovery from inactivation,but did not affect its activation curve.Conclusion:In addition to blocking other voltage-gated ion channels,total flavonoid can block Na+ channels in guinea-pig ventricular myocytes.Total flavonoid acts as inactivation stabilizer of Na+ channels in cardiac tissues.更多还原