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目的 :研究 9 蒽羧酸 (9 AC)对豚鼠心室肌动作电位 (AP)和L型Ca电流 (ICa)的影响。方法 :电流钳配合制霉菌素膜穿孔方法记录心室肌动作电位 ,用全细胞式膜片钳 (Whole cellrecording)技术记录ICa。结果 :在低Cl-状态下 ,β肾上腺素能受体激动剂异丙肾上腺素 (ISO)可使动作电位时程 (APD)明显延长。 9 AC单独使用时对AP无作用 ,但在ISO的作用下 ,蛋白磷酸酶抑制剂 9 AC可使APD进一步延长 ,ISO和 9 AC的作用可被Ca2 + 通道阻断剂硝苯地平 (3μmol/L)所反转。电压箝实验发现 ,在 β 肾上腺素能受体激动剂ISO激发下 ,9 AC使ICa的幅度进一步增加。结论 :9 AC与ISO有协同作用。本文结果提示 9 AC敏感性蛋白磷酸酶参与Ca2 + 通道的调控过程。
AIM: To investigate the effects of 9 anthracene carboxylic acid (9 AC) on ventricular action potential (AP) and L-type Ca (ICa) in guinea pigs. Methods: Current clamps were used to record ventricular action potential with nystatin membrane perforation and ICa was recorded by whole cell recording technique. RESULTS: In the low Cl-state, isoproterenol (ISO), a beta adrenergic receptor agonist, significantly prolonged the action potential duration (APD). 9 AC alone had no effect on AP, but under the action of ISO, the protein phosphatase inhibitor 9 AC prolonged the APD. The effect of ISO and 9 AC could be blocked by Ca2 + channel blocker nifedipine (3μmol / L) reversed. Voltage clamp experiments showed that 9 AC increased the amplitude of ICa further with the activation of the beta adrenergic receptor agonist ISO. Conclusion: 9 AC has a synergistic effect with ISO. Our results suggest that 9 AC-sensitive protein phosphatases are involved in the regulation of Ca2 + channels.