（+）-普萘洛尔对二氢哇巴因变力作用与刺激频率关系的影响。

The influence of (+)-propranolol on the inotropic effect of dihydro-ouabain in relation to stimulation frequency.

Ebner F, Reiter M

Naunyn Schmiedebergs Arch Pharmacol. 1979 Jun;307(2):105-13. doi: 10.1007/BF00498451.

Abstract

The influence of (+)-propranolol, 10(-6) to 4 x 10(-5) mol/l, upon the positive inotropic effect of dihydro-ouabain was studied on guinea-pig papillary muscle. At 1 Hz, negative inotropically effective concentrations of (+)-propranolol decreased the inotropic effectiveness of the glycoside. 2. For equivalent diminution of the basal force of contraction, either by reduction of stimulation frequency or by increasing concentrations of (+)-propranolol, a similar decrease in the inotropic effectiveness of dihydro-ouabain was observed. In contract, reduction of [Ca2+]o had almost no effect on the effectiveness of the glycoside. 3. The inhibitory effect of (+)-propranolol on the inotropic effectiveness of dihydro-ouabain declined with reduction of stimulation frequency. At any stimulation frequency tested, the inhibitory effect of (+)-propranolol was proportional to the effect of a reduction of that particular frequency to the rested-state condition in the absence of (+)-propranolol. 4. The results are consistent with the hypothesis that the inhibition of the excitation-coupled sodium influx by (+)-propranolol is the cause of its inhibiting effect on the effectiveness of dihydro-ouabain.

摘要

在豚鼠乳头肌上研究了浓度为10⁻⁶至4×10⁻⁵mol/l的(+)-普萘洛尔对二氢哇巴因正性肌力作用的影响。在1Hz时，具有负性肌力作用的(+)-普萘洛尔浓度降低了糖苷的肌力效应。2. 为了通过降低刺激频率或增加(+)-普萘洛尔浓度同等程度地减弱基础收缩力，观察到二氢哇巴因的肌力效应有类似程度的降低。相反，降低细胞外钙离子浓度对糖苷的效应几乎没有影响。3. (+)-普萘洛尔对二氢哇巴因肌力效应的抑制作用随刺激频率降低而减弱。在任何测试的刺激频率下，(+)-普萘洛尔的抑制作用与该特定频率降至无(+)-普萘洛尔时静息状态的效应成比例。4. 这些结果与以下假设一致，即(+)-普萘洛尔对兴奋-偶联钠内流的抑制是其对二氢哇巴因效应产生抑制作用的原因。