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目的 探讨四氢小蘖碱 (THB)对豚鼠单个心肌细胞钙通道的作用。方法 利用膜片钳全细胞记录方法检测四氢小蘖碱对豚鼠心肌细胞钙离子电流峰值的变化。结果 当钳制电位为 - 40 m v,去极化至 0 m v,保持时间为 2 5 0 ms,THB1μm ol· L- 1和 10 μm ol· L- 1使心肌细胞钙电流峰值分别从 (30 0 .75± 5 4.6 9) PA和 (4 2 0 .45± 94.45 ) PA降至 (176 .75±2 7.16 )和 (15 5 .5 8± 82 .2 3) PA (P <0 .0 1) ,其下降百分率分别为 41.2 3%和 6 3.0 2 % ,给药前后钙电流 (Ica)的翻转电位不变 ,其最大激活电位为 0 mv,给药后经台氏液冲洗 ,Ica峰值逐渐恢复。结论 THB对心肌细胞钙通道具有阻滞作用 ,并呈浓度依赖性
Objective To investigate the effects of tetrahydrobiopterin (THB) on the calcium channels in single cardiomyocytes of guinea pigs. Methods Patch clamp whole cell recording method was used to detect the change of calcium ion current in guinea pig cardiomyocytes induced by tetrahydperberine. Results When the clamping potential was-40 mv, depolarization to 0 mv, holding time was 250 ms, THB1 μmol · L-1 and 10 μmol · L-1, the peak of calcium current in cardiomyocytes were decreased from (300) to 75 ± 5 4.6 9) PA and (42.045 ± 94.45) PA decreased to (176.75 ± 2 7.16) and (15 5 .5 8 ± 82 .2 3) PA (P <0.01) , The decreasing percentage was 41.2 3% and 6 3.0 2% respectively. The turnover potential of calcium current (Ica) did not change before and after administration, and its maximum activation potential was 0 mv. After the drug was administered, the Ica peak gradually recovered . Conclusion THB has a block effect on calcium channels in cardiomyocytes in a concentration-dependent manner