去甲肾上腺素和异丙肾上腺素与α及β受体阻断物质联合应用对心脏浦肯野纤维动作电位的影响。

The effects of noradrenaline and isoprenaline on the repolarization phase of the action potential have been studied in the Purkinje fibres of sheep heart, electrically driven at constant rates.2. Isoprenaline (2, 5 and 8 x 10(-8) g/ml.) increases the slope of phase 2 of repolarization and decreases the plateau length; the resulting decrease in action potential duration is concentration dependent, but not rate dependent.3. The effect of isoprenaline on the action potential duration is entirely blocked by propranolol (10(-7) g/ml.) and unaffected by phentolamine (5 x 10(-7) g/ml.).4. In phentolamine (5 x 10(-7) g/ml.) pretreated preparations the response induced by noradrenaline (5 x 10(-8), 1 and 5 x 10(-7) g/ml.) is very similar to that induced by isoprenaline.5. In propranolol (2.5 x 10(-7) g/ml.) pretreated preparations noradrenaline causes a lengthening of the plateau phase and an increase in action potential duration.6. The relationship of these results to the presence of both alpha- and beta-receptors in cardiac Purkinje fibres is discussed.

研究了去甲肾上腺素和异丙肾上腺素对绵羊心脏浦肯野纤维动作电位复极化阶段的影响，这些纤维以恒定速率进行电驱动。
异丙肾上腺素（2×10⁻⁸、5×10⁻⁸和8×10⁻⁸克/毫升）增加复极化2期的斜率并缩短平台期长度；动作电位时程的相应缩短呈浓度依赖性，但不呈速率依赖性。
异丙肾上腺素对动作电位时程的作用完全被普萘洛尔（10⁻⁷克/毫升）阻断，且不受酚妥拉明（5×10⁻⁷克/毫升）影响。
在经酚妥拉明（5×10⁻⁷克/毫升）预处理的标本中，去甲肾上腺素（5×10⁻⁸、1×10⁻⁷和5×10⁻⁷克/毫升）诱导的反应与异丙肾上腺素诱导的反应非常相似。
在经普萘洛尔（2.5×10⁻⁷克/毫升）预处理的标本中，去甲肾上腺素导致平台期延长和动作电位时程增加。
讨论了这些结果与心脏浦肯野纤维中α和β受体的存在之间的关系。

Effects of noradrenaline and isoprenaline, in combination with - and -receptor blocking substances, on the action potential of cardiac Purkinje fibres.