目的 研究薯蓣皂苷含药血清对正常大鼠心室肌细胞钠离子通道电流（I_Na）的影响，探讨其保护心肌细胞及抗心律失常的离子机制。方法 大鼠ig给予300 mg/kg薯蓣皂苷，2次/d，连续4 d，末次给药后1 h从腹主动脉取血，离心分离得含药血清；采用酶解法分离大鼠单个心室肌细胞，以全细胞膜片钳技术记录薯蓣皂苷含药血清低、中、高剂量（1、10、100 μL）分别对大鼠正常心室肌细胞I_Na的影响。结果 薯蓣皂苷含药血清1、10、100 μL均使I-V曲线下移，内向电流增加；1 μL薯蓣皂苷含药血清使I_Na峰值增大，而10、100 μL的薯蓣皂苷含药血清使I_Na峰值由（-52.10±3.80）pA/pF变为（-76.44±4.09）pA/pF和（-81.96±4.70）pA/pF（P<0.01），呈剂量依赖性。1、10、100 μL薯蓣皂苷含药血清剂量依赖性加速钠离子通道激活过程，半数稳态激活电压分别由（-57.69±1.86）mV变为（-59.71±2.57）、（-66.56±1.32）（P<0.01）、（-68.52±3.91）mV（P<0.01），但对失活过程无明显影响。1、10、100 μL薯蓣皂苷含药血清剂量依赖性加速钠离子通道的复活过程，拟合复活曲线τ值由（150.73±21.49）ms分别变为（143.19±13.88）、（84.83±18.03）（P<0.01）、（80.63±13.89）ms（P<0.01）。结论 薯蓣皂苷含药血清通过加快激活过程及复活过程促进钠离子的内流。

Objective To investigate the effects of serum containing dioscin on sodium current (I_Na) and reveal the mechanisms of cardioprotection and antiarrhymias. Methods Serum was obtained from the aortaventralis from Wistar rats after ig administration 4 d of dioscin 300 mg/kg, twice daily for 4 d. Single ventricular myocytes were isolated from adult rat hearts by enzymatic dissociation and the effects of dioscin on I_Na were observed by whole-cell patch clamp. Results Serum containing dioscin shifted downward the I-V curve with increased peak current density. With the effects of 1, 10, and 100 μL serum containing dioscin, the peak current density was dose-dependently changed from (-52.10 ± 3.80) pA/pF to (-76.44 ± 4.09) pA/pF and (-81.96 ± 4.70) pA/pF, respectively (P < 0.01 vs control); Dioscin facilitated the activation process with the inactivation process unchanged. The half activation potential was changed from (-57.69 ± 1.86) mV to (-59.71 ± 2.57) mV, ( -66.56 ± 1.32) mV (P < 0.01 vs control), and (-68.52 ± 3.91) mV (P < 0.01 vs control), respectively; The recovery process of sodium channel was accelerated by 1, 10, and 100 μL serum containing dioscin with the recovery constant τ changed from (150.73 ± 21.49) ms to (143.19 ± 13.88) ms, (84.83 ± 18.03) ms (P < 0.01 vs control), and (80.63 ± 13.89) ms (P < 0.01 vs control). Conclusion Serum containing dioscin could increase the sodium current by facilitating the activation process and accelerating the recovery process of sodium channel.

天津医科大学科学基金资助项目（2011ky35）；黑龙江省自然科学基金资助项目（D2007-104）