Effect of adrenomedullin on excitation-contraction coupling and abnormal automaticity in excised human atrial muscles

肾上腺素（AM）对骨髓细胞的直接影响仍然是相等的。在补充中，该机制解释了心脏肌肉的直接行动不清楚。我们已经调查了AM在行动潜力和对纸口罩的直接影响，特别是从几内亚猪右， ventricle。在.的基础上。Concentration ranging from 10 -8-D1 to 10-D1-6-D1 M caused a slight prolongation of action potential duration at 20%level of the repolarization and an increase of Oracle ed tension。这一效果。Was abolished in the presence of L型CaイイD12+イエD1 channel blocker， suggesting that the positive inotropic effect produced by AM is due to enhancement of L型CaイD12+イエD1 possibly via activation of intracellular cAMP。However，它被报道，显示出一种消极的、非线性的影响。关于兔子和蜗牛的心脏肌肉。在另一手上，我们发现这可能是不可能的，那么在兔子Sinoatrial节点细胞中起搏器的动作潜力的任何影响。进一步研究两种直接行动及其节点上的心脏博物馆，包括人类myocardial细胞的各种哺乳动物物种。

Direct effect of adrenomedullin (AM) on myocardial cells is as yet equivocal. In addition, the mechanism underlying the direct action of AM on cardiac muscle reams not clear. We have investigated the direct effect of AM on action potential and contraction of papillary muscle excised from guinea pig right, ventricle. The substances at. Concentration ranging from 10ィイD1-8ィエD1 to 10ィイD1-6ィエD1 M caused a slight prolongation of action potential duration at 20% level of the repolarization and an increase of developed tension. This effect. Was abolished in the presence of L-type CaィイD12+ィエD1 channel blocker, suggesting that the positive inotropic effect produced by AM is due to enhancement of L-type CaィイD12+ィエD1 possibly via activation of intracellular cAMP. However, it is reported that AM showed a negative inotropic effect. On rabbit and ferret cardiac muscle. On the other hand, we found that AM might not, induce any effect on slope of pacemaker potential of action potential in rabbit sinoatrial node cell. Further studies into both direct action and its node on cardiac muscles of various mammalian species including human myocardial cells are necessary.