Increase in Ca++ sensitivity of the contractile system by MCI-154, a novel cardiotonic agent, in chemically skinned fibers from the guinea pig papillary muscles.
Increase in Ca++ sensitivity of the contractile system by MCI-154, a novel cardiotonic agent, in chemically skinned fibers from the guinea pig papillary muscles.
复制标题
MCI-154（一种新型强心剂）在豚鼠乳头肌的化学剥皮纤维中增加收缩系统的 Ca 敏感性。
DOI：
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发表时间：
1987
影响因子：
3.5
通讯作者：
M. Endo
中科院分区：
文献类型：
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作者：
Y. Kitada;A. Narimatsu;N. Matsumura;M. Endo
用化学剥皮的豚鼠乳头肌纤维束研究了新型强心药MCI-154对收缩蛋白系统和肌浆网（SR）的影响。在用50 μ g/ml皂苷处理的去皮肌纤维中，MCI-154以浓度依赖性方式（10（-7）至10（-4）M）使-log[Ca++] M-张力关系曲线向左和向上移动。这也在用250微克/毫升皂苷处理的去皮肌纤维中得到证实，皂苷不仅破坏表面膜，而且破坏SR的功能。舒马唑（10（-4）M）使-log[Ca++] M-张力关系曲线向左移动，但其效果比MCI-154的效果弱约100倍。与MCI-154不同，舒马唑对-log[Ca++]M 4.4诱导的最大张力发展几乎没有影响。米力农不影响Ca ~（++）诱导的皮肤心肌纤维张力的发展。高浓度的MCI-154（10（-4）M）也使无游离Ca++离子时的-log[Mg-ATP] M-张力曲线（钟形曲线）的振幅向上增加。MCI-154在浓度为10（-6）和10（-4）M时，50 μ g/ml皂苷处理的皮肤纤维中SR的Ca++摄取的初始速率和平台期略有增加。MCI-154对SR中Ca++诱导的Ca++释放机制没有影响。这些结果表明，收缩蛋白系统的Ca++敏感性增加是MCI-154的正性肌力作用机制的至少部分原因。（250字处删节）
The effects of MCI-154, a novel cardiotonic agent, on the contractile protein system and the sarcoplasmic reticulum (SR) were investigated by using thin bundles of chemically skinned fibers from the guinea pig papillary muscles. In the skinned muscle fibers treated with 50 micrograms/ml of saponin, MCI-154 shifted the -log[Ca++]M-tension relation curve to the left and upward in the concentration-dependent manner (10(-7) to 10(-4) M). This was confirmed also in the skinned muscle fibers treated with 250 micrograms/ml of saponin which destroyed not only the surface membrane but also the function of SR. Sulmazole (10(-4) M) shifted the -log[Ca++]M-tension relation curve to the left but the effect was about 100 times less potent than that of MCI-154. Unlike MCI-154, sulmazole had little effect on the maximum tension development induced by -log[Ca++]M 4.4. Milrinone did not affect the Ca++-induced tension development in the skinned cardiac fibers. Higher concentration of MCI-154 (10(-4) M) also increased amplitude of -log[Mg-ATP]M-tension-curve in the absence of free Ca++ ion (bell-shaped curve) to the upward. Initial rate and plateau phase of Ca++ uptake by the SR in the skinned fibers treated with 50 micrograms/ml of saponin was increased slightly by MCI-154 at the concentrations of 10(-6) and 10(-4) M. MCI-154 had no effect on the Ca++-induced Ca++ release mechanism in the SR. These results suggest that an increase in Ca++ sensitivity of the contractile protein system is responsible for, at least in part, the mechanism of the positive inotropic action of MCI-154.(ABSTRACT TRUNCATED AT 250 WORDS)