白藜芦醇对豚鼠心室肌细胞L型钙通道的影响

目的研究白藜芦醇(resveratrol,RES)对豚鼠心室肌细胞L型钙通道的影响。方法酶解法分离单个豚鼠心室肌细胞,采用全细胞膜片钳技术记录白藜芦醇对豚鼠单个心室细胞L型钙通道电流(ICa-L)的影响。结果不同浓度的RES明显抑制ICa-L,1、10、100μmol.L-1L的RES使其峰电流密度从(12.96±1.48)pA/pF减少到(11.36±1.59)、(9.96±1.51)和(7.77±0.68)pA/pF(n=6,P<0.01),冲洗后可恢复至(11.85±0.83)pA/pF。RES可使ICa-L的I-U关系曲线上移,其形状和峰值电压保持不变;RES还可使通道的激活曲线右移,但失活曲线和失活恢复时间无改变。结论白藜芦醇通过延长L型钙通道激活过程而明显抑制ICa-L,减少细胞外的钙离子内流,延长有效不应期,从而发挥抗心律失常作用。

Effects of resveratrol on L-type calcium current (ICa-L) in guinea pig ventricular myocytes

Aim To investigate effects of different concentrations of resveratrol (RES) on L-type calcium channels in guinea pig ventricular myocytes. Methods Enzyme digestion was used to isolate single ventricular myocyte and whole cell patch clamp technique was used to record L-type calcium current. Results RES inhibited ICa-L in a concentration- dependent manner .The application of 1、10、100 μmol·L-1 RES reduced the density of peak ICa-L from ( -12.96±1.48 ) pA/pF to (-11.36±1.59)pA/pF (n= 6,P<0.01), (-9.96±1.51) pA/pF (n= 6, P< 0.01) and (-7.77±0.68) pA/pF (n= 6,P<0.01) pA/pF at 0 mV, respectively.ICa-L came back to (-11.85±0.83) pA/pF after washout. RES remarkably shifted activation curve to the right, and delayed the voltage-dependent steady-state activation of calcium current. The half activation potential (V1/2) was ( -32.32801±0.366 )mV in the control and(-23.36414±0.94711)mV in the presence of RES 1 μmol·L-1. The slope factor(k) was (8.86352±0.37865) in the control and (8.7592±0.8847 ) in the presence of RES 1 μmol·L-1(n= 6,P<0.05). Steady-state inactivation curve was not affected markedly, also V1/2 value and k value in the presence of RES 1 μmol·L-1 were not markedly different from those of the control. The recovery time from inactivation was not changed significantly. Conclusion RES decreased the amplitude of L-type calcium current, which would be one of cardiac protection mechanisms of the drug. And slowing the activation procession of ICa would help to its cardiac protection.