芍药苷对大鼠心肌细胞L钙通道的阻断作用

目的　在单个大鼠心肌细胞上 ,研究芍药苷对L型钙通道的阻断作用。方法　采用全细胞膜片钳技术。结果　芍药苷浓度依赖性阻断ICa ,L,其IC50 为 387μmol·L- 1 。应用 40 0 μmol·L- 1 芍药苷后 ,ICa,L最大电流幅度下降 51 % ,但I U曲线的形态和反转电位没有变化 ,激活曲线也没有明显的改变 ;失活曲线向较负电压的方向偏移约 8 3mV ,通道从失活中恢复的时间明显延长 ,由给药前的 (96± 1 7)ms增至 (1 85± 2 8)ms ;芍药苷的阻断作用没有显示出频率依赖性。结论　芍药苷对心肌细胞ICa ,L有阻断作用

Blockade of paeoniflorin on L-type calcium channel in isolated rat ventricular myocytes

AIM To study the blockade of paeoniflorin (Pae) on Ca 2+ channel in rat ventricular myocytes. METHOD Whole-cell patch clamp technique was used. RESULTS Pae inhibited I Ca,L in a dose-dependent manner, with a half-blocking concentrations (IC 50 ) of 387 μmol·L -1 . 400 μmol·L -1 Pae inhibited I Ca ,L by 51%, did not alter the shape of the I-U curve, reversal potential and the steady-state activation curve of I Ca,L . But it markedly shifted the steady-state inactivation curve of I Ca,L towards more negative potential by 8 3 mV, and postponed the recovery of I Ca,L from inactivation state, with time constant of (96±17) ms and (185±28) ms in control and Pae, respectively. CONCLUSION Pae has obvious inhibition on the Ca 2+ channel in rat ventricular myocytes.