Effect of diltiazem on electrical and mechanical activity of isolated cardiac ventricular muscle of guinea pig.
Effect of diltiazem on electrical and mechanical activity of isolated cardiac ventricular muscle of guinea pig.
复制标题
地尔硫卓对豚鼠离体心室肌电和机械活动的影响。
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
A. Kiyomoto
中科院分区：
文献类型：
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作者：
H. Nakajima;M. Hoshiyama;K. Yamashita;A. Kiyomoto
地尔硫卓是一种新的1，5-苯并硫氮类化合物，它能拮抗钙离子，从而降低乳头肌的收缩力。地尔硫卓对钙离子的拮抗比约为1：1。1：100。较低浓度的地尔硫卓(2.2×10~(-6)M)可降低细胞内记录的静息和动作电位，但不显著降低细胞内的收缩力。当药物浓度增加到2.2×10~(-5)M时，只有动作电位的最大上升速率减小，而地尔硫卓浓度为1.1×10~(-4)M时动作电位的其他参数也受到影响。静息电位无明显变化。在收缩力几乎消失的情况下(1.1×10~(-4)M)，膜的兴奋性保持不变。结论：地尔硫卓是心肌细胞的兴奋-收缩解偶联剂，该化合物可能通过降低细胞内可用于收缩机制的游离钙离子浓度而表现出负性变力作用。
Diltiazem, a new 1,5-benzothiazepine derivative, antagonized calcium ion and thus caused a reduction in the contractile force of isolated papillary muscle. The antagonistic ratio of diltiazem to calcium ion was estimated to be approx. 1: 100. A lower concentration of diltiazem (2.2 x 10(-6) M) decreased the contractile force without affecting significantly the intracellularly recorded resting and action potentials. When the concentration of the compound was increased to 2.2 x 10(-5) M, only the maximum rate of rise of the action potential was reduced, while the other parameters of the action potential were also affected at 1.1 x 10(-4) M diltiazem. There was no significant change in the resting potential. Under conditions where the contractile force almost disappeared (1.1 x 10(-4) M), the membrane excitability was retained. It is concluded that diltiazem is an excitation-contraction uncoupler in the cardiac muscle cell and that the compound may exhibit its negative inotropic action by reducing in some way the intracellular concentration of free calcium ion available for the contractile mechanism.