论文部分内容阅读
实验用全细胞膜片钳技术在单个豚鼠心室肌细胞上研究了腺苷 (Ado)对正常及异丙肾上腺素 (Iso)致豚鼠心室肌细胞动作电位、迟后除极 (DAD)、L 型钙电流 (ICa.L)和短暂内向电流 (Iti)的作用。结果表明 :(1)Ado在2 0～ 10 0 μmol/L时对豚鼠心室肌细胞动作电位和ICa .L无明显直接作用 ,但却可明显降低Iso所致的动作电位时程(APD)延长和ICa .L峰值增大 ,Iso (10nmol/L)使细胞APD50 从 3 40± 2 1ms延长到 486± 2 8ms (P <0 0 1) ,APD90从 3 61± 17ms延长至 5 0 1± 2 9ms (P <0 0 1) ;ICa .L峰值从 - 6 5 3± 1 4pA/pF增大到 - 18 2 8± 2 4pA/pF (P <0 0 1) ,电流电压曲线明显左移和下移 ;Ado (5 0 μmol/L)使APD50 和APD90 降至 40 3± 19ms和 419± 2 6ms ,但并不影响动作电位其它参数 ,使ICa.L峰值降低至 - 10 2± 1 5pA/pF (P <0 0 1)。 (2 )Iso (3 0nmol/L)可诱发心室肌细胞产生DADs,其发生率为 10 0 % ;Ado (5 0 μmol/L)可完全抑制Iso引发DADs;细胞经 - 40～ +2 0mV、时程 2s的除极电压 ,Iso (3 0nmol/L)诱导出Iti,其发生率为 10 0 % ;Ado (5 0 μmol/L)可明显抑制Iso致Iti的发生 ,其发生率降为 14 3 %。研究结果提示 ,Ado对豚鼠心室肌细胞动作电位和ICa.L无明显直接作用 ,但却可显著降低Is
The effects of adenosine (Ado) on the action potentials of normal and isoproterenol (Iso) -induced ventricular myocytes in guinea pig ventricular myocytes were determined by whole cell patch clamp technique in a single guinea pig ventricular myocytes. Current (ICa.L) and transient inward current (Iti). The results showed that: (1) Ado at 20 ~ 100 μmol / L had no direct effect on the action potential and ICa. L of guinea pig ventricular myocytes, but significantly reduced the prolonged action potential duration (APD) induced by Iso L and ICa · L increased, APD50 prolonged from 340 ± 2 1ms to 486 ± 2 8ms (P <0.01) with Iso (10nmol / L), and APD90 prolonged from 3161 ± 17ms to 501 ± 2ms The peak value of ICa · L increased from -653 ± 14pA / pF to -1828 ± 24pA / pF (P <0.01), and the current-voltage curve was significantly shifted to the left Ado (50 μmol / L) decreased APD50 and APD90 to 40 3 ± 19 ms and 419 ± 2 6 ms, but did not affect the other parameters of action potential. The peak value of ICa.L decreased to -10 2 ± 15 pA / pF (P <0 0 1). (2) Iso (300 nmol / L) induced DADs in ventricular myocytes at a rate of 10%. Ado (50 μmol / L) completely inhibited Iso-induced DADs; Isolation time of 2s, Iso (30nmol / L) induced Iti, the incidence was 100%; Ado (50μmol / L) can significantly inhibit the occurrence of Iso induced Iti, the incidence was reduced to 14 3%. The results suggest that, Ado on guinea pig ventricular myocytes and action potential and ICa.L no significant direct effect, but it can significantly reduce the Is