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目的 研究钙增敏剂MCI 15 4对内毒素休克大鼠左心室肌原纤维ATP酶活性的影响。方法 利用心室肌原纤维制备 ,测定其在不同钙浓度的激活液中的ATP酶活性。结果 内毒素休克组心肌肌原纤维在不同pCa(-log[Ca2 +] )溶液中的ATP酶活性及最大ATP酶活性均明显低于假休克组 ,ATP酶 pCa曲线向右移位约 0 .35个pCa单位 ,曲线的中位值pCa50 (产生 5 0 %最大ATP酶活性所对应的pCa)明显降低。 5×10 -5mol/L甲腈吡酮对上述异常无明显的纠正作用。内毒素休克大鼠心室肌原纤维经含 1× 10 -5mol/L的MCI 15 4的激活液处理后 ,各pCa点ATP酶活性及最大ATP酶活性均明显增加 ,显著高于内毒素休克组和甲腈吡酮组 ;ATP酶 pCa曲线向左移位约 0 .4个pCa单位 ,pCa50 值增加 ,显著高于内毒素休克组和甲腈吡酮组值 ,与假休克组值无明显差别。结论 内毒素休克后 ,心肌肌原纤维活力下降 ,ATP酶活性降低 ;钙增敏剂MCI 15 4可通过增加心肌收缩蛋白对钙的敏感性而提高心肌肌原纤维活力 ,增加ATP酶活性
Objective To investigate the effects of calcium sensitizer MCI 15 4 on left ventricular myofibrillar ATPase activity in endotoxic shock rats. Methods Preparation of ventricular myofibrils was used to measure the activity of ATPase in different concentrations of calcium. Results The ATPase activity and maximal ATPase activity of myocardial myofibrils in different pCa (-log [Ca2 +]) solutions were significantly lower than those in sham shock group. The ATPase pCa curve shifted to the right by about 0. With 35 pCa units, the median pCa50 of the curve (pCa corresponding to a 50% maximal ATPase activity) was significantly reduced. 5 × 10 -5 mol / L tetracimide did not significantly correct the above abnormalities. Endotoxic shock rats ventricular myofibrils treated with 1 × 10 -5 mol / L MCI 15 4 activation liquid, each pCa ATPase activity and maximum ATPase activity were significantly increased, significantly higher than endotoxin shock group And acinarone group; ATPase pCa curve shift to the left about 0.4 units of pCa, pCa50 increased, significantly higher than the endotoxic shock group and the value of the group nitrile group, and sham group no significant difference . Conclusions After endotoxin shock, the activity of myocardial myofibrils decreased and the activity of ATPase decreased. Calcium sensitizer MCI 15 4 increased myocardial myofibrillar activity and increased ATPase activity by increasing the sensitivity of myocardial contractile proteins to calcium