Kazan State Medical University, Federal Agency for Health Care and Social Development.
Acta Naturae. 2011 Apr;3(2):103-12.
The effects of the selective β(2)-adrenoreceptor agonist (fenoterol) on the functioning of mouse atrial were studied using both tensometry and fluorescent methods. It has been demonstrated that with the use of a high concentration of fenoterol (in the range of 1-50 µM), there is a more significant positive inotropic effect observed within a shorter period of time. In the case of relatively low doses of fenoterol (1 and 5 µM), its contractility effects are observed 20 min after the application of agonist, whereby in the case of high concentrations (25, 50 and 300 µM), the effects appear within the first minutes. During the first 10-15 min, 5 µM fenoterol causes an increase in the amplitude of Ca-signals in cardiomyocytes (this indicates an increase in the concentration of Ca ions during systole) and the activation of NO synthesis. However, after 20 min, the production of NO decreases; while the amplitude of Ca-signals remains high. The application of 50 µM fenoterol leads to a rapid increase in the amplitude of Ca-signals: at the same time, it causes a decrease in the production of NO, which we found to begin to increase after 10 min of agonist application. It is suggested that the dynamics of the positive inotropic effect occurring under pharmacological stimulation of β(2)-adrenoreceptors depend on the rate of increase in the amplitude of Ca-signals and on the degree of NO synthesis.
采用张力测定法和荧光法研究了选择性β（2）-肾上腺素能受体激动剂（fenoterol）对小鼠心房功能的影响。研究表明，使用高浓度的 fenoterol（1-50 μM 范围内），在较短的时间内观察到更显著的正性肌力作用。在相对低剂量的 fenoterol（1 和 5 μM）的情况下，其收缩力作用在激动剂应用 20 分钟后观察到，而在高浓度（25、50 和 300 μM）的情况下，作用在最初的几分钟内出现。在最初的 10-15 分钟内，5 μM fenoterol 导致心肌细胞 Ca 信号幅度增加（这表明收缩期间钙离子浓度增加）和 NO 合成的激活。然而，20 分钟后，NO 的产生减少；而 Ca 信号的幅度保持高。应用 50 μM fenoterol 导致 Ca 信号幅度迅速增加：同时，它导致 NO 产生减少，我们发现它在激动剂应用 10 分钟后开始增加。建议，在β（2）-肾上腺素能受体药理学刺激下发生的正性肌力作用的动力学取决于 Ca 信号幅度增加的速率和 NO 合成的程度。
