17β-雌二醇对豚鼠心室肌细胞动作电位及L型钙通道电流的影响

Effects of 17β-Estradiol on Action Potential and L-Type Calcium Current in Guinea Pig Ventricular Myocytes

探讨雌激素对心血管保护作用的机制，采用标准玻璃微电极技术及全细胞膜片钳技术观察17β-雌二醇（ES）对豚鼠心室乳头肌细胞动作电价的影响及其对分离的豚鼠心室肌细胞的L型钙通道电流的作用。结果：30μmol／LES灌流心肌30min可明显缩短动作电位时程；复极20％动作电位时程及复极50％动作电位时程分别由146±22ms，213±21ms缩短至87±6ms，107±11ms（P均＜0．01）。1，10，20，30μmol／LES是浓度依赖性抑制L型钙通道电流（P均＜0．01），抑制率分别为8％，18％，33％，43％。结论：ES是一种内源性的钙离子通道拮抗剂，这可能是其心血管保护作用的重要机制之一．

To investigate the protective mechanism of estrogen on cardiovascular diseases,standard glass microelectrode method and whole cell patch clamp technique were used to study the effects of 17β-estradiol on action potential of guinea pig ventricular papillary muscle and L-type calcium current of ventricular myocytes. Results: ES 30pmol/L, shortened action potential durntion (APD),especially 20% of APD and 50% of APD, (from 146±22 ms,213±21 ms to 87±6 ms, 107±11 ms, P＜0. 01 respectively). Different concentrations of ES 1, 10, 20, 30 μmol/L decreased L-type calcium peak current. The inhlbition rate were 8%, 18 %, 33 %, 43 % respectively (P＜0. 01 ). Conclusion: 17β-estradiol possess characteristics of calcium channel blocker which may be an important aspect of its protective effects.