Zhao Hua-Chen, Wu Dong-Mei, Cui Xiang-Li, Wu Bo-Wei
Departments of Physiology, Shanxi Medical University, Taiyuan, Shanxi 030001, China.
Sheng Li Xue Bao. 2004 Aug 25;56(4):476-80.
To study the inotropic effect of enhanced Na(+)-Ca(2+) exchange in the rat papillary muscles and isolated heart, the developed tension in the rat papillary muscles was measured and the left ventricular functions were assessed in the isolated rat heart. E-4031, a selective activator for Na(+)-Ca(2+) exchange in rats, concentration-dependently increased the developed contractile tension in the rat papillary muscles (P<0.05, n=6) and the left ventricular functions in the isolated heart; KB-R7943, a selective Na(+)-Ca(2+) exchange inhibitor, exhibited opposite effect. A combination of 0.5 micromol/L ouabain and 3.0 micromol/L E-4031 resulted in a potentiation of the developed contractile tension of the rat papillary muscles from 0.25+/-0.03 g to 0.29+/-0.04 g. The combination also enhanced the augmentation of the left ventricular functions induced by ouabain. These results indicate that E-4031 exerts a positive inotropic effect on the rat papillary muscles and isolated heart via increasing the activity of Na(+)-Ca(2+) exchange, and potentiates the positive inotropic effects of ouabain.
为研究增强的钠钙交换在大鼠乳头肌和离体心脏中的变力作用，测量了大鼠乳头肌的收缩张力，并评估了离体大鼠心脏的左心室功能。E-4031是大鼠钠钙交换的选择性激活剂，它能浓度依赖性地增加大鼠乳头肌的收缩张力（P<0.05，n=6）以及离体心脏的左心室功能；KB-R7943是一种选择性钠钙交换抑制剂，其作用相反。0.5微摩尔/升哇巴因与3.0微摩尔/升E-4031联合使用，可使大鼠乳头肌的收缩张力从0.25±0.03克增强至0.29±0.04克。该联合用药还增强了哇巴因诱导的左心室功能增强作用。这些结果表明，E-4031通过增加钠钙交换活性，对大鼠乳头肌和离体心脏发挥正性变力作用，并增强哇巴因的正性变力作用。
