Interactions of ouabain and noradrenaline in isolated rabbit's atria
Interactions of ouabain and noradrenaline in isolated rabbit's atria
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哇巴因和去甲肾上腺素在离体兔心房中的相互作用
DOI：
10.1111/j.1476-5381.1969.tb07996.x
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发表时间：
1969
影响因子：
7.3
通讯作者：
N. Toda
中科院分区：
文献类型：
--
作者：
N. Toda
1本研究采用家兔离体交感神经-心房标本、常规心房标本和左心房标本，研究哇巴因和去甲肾上腺素对S-A结起搏纤维跨膜电位、起搏频率和左心房收缩力的相互作用。2在起搏动作电位中，中毒浓度的哇巴因使最大舒张电位降低，早期复极加快，晚期复极减慢。舒张期起搏膜产生振荡电位。3刺激节后交感神经引起舒张期除极斜率增加，导致起搏频率加快。在存在哇巴因的情况下，在显示哇巴因诱导心动过缓的制剂中，神经刺激显著改变了起搏器动作电位构型，但在显示哇巴因诱导心动过速的制剂中，神经刺激未改变电位构型。心脏去甲肾上腺素改变了心脏起搏器膜的离子渗透性，在心脏收缩期，但它没有影响。交感神经刺激短暂纠正了过冲和复极的心房动作电位改变的毒性浓度的哇巴因。4.哇巴因治疗浓度和毒性浓度均不影响交感神经刺激的正性变时效应。哇巴因使外源性去甲肾上腺素的浓度-变时性反应曲线向左移动，但未使酪胺的曲线移动。5哇巴因和去甲肾上腺素对收缩率与张力的关系有不同的影响。去甲肾上腺素的正性肌力作用没有显着改变治疗浓度的哇巴因，但它被抑制毒性浓度。
1 The present study was made using sympathetic nerve‐atria preparations, conventional atrial preparations and left atria isolated from rabbits in order that interactions of ouabain and noradrenaline on the transmembrane potential of S‐A nodal pacemaker fibres, the pacemaker rate and the contractile force of the left atrium could be investigated. 2 In pacemaker action potentials, the maximal diastolic potential was decreased, the early repolarization was accelerated and the late repolarization was slowed by toxic concentrations of ouabain. Oscillating potentials of the diastolic pacemaker membrane were produced. 3 Stimulation of the postganglionic sympathetic nerve caused an increase in the slope of diastolic depolarization, resulting in an acceleration of the pacemaker rate. In the presence of ouabain, the pacemaker action potential configuration was significantly altered by nerve stimulation in preparations which showed ouabain‐induced bradycardia, but the potential configuration was not changed by nerve stimulation in preparations which showed ouabain‐induced tachycardia. Cardiac noradrenaline altered the ion permeability of the cardiac pacemaker membrane during diastole, but it had no effect during systole. Sympathetic nerve stimulation transiently corrected the overshoot and the repolarization of atrial action potentials altered by toxic concentrations of ouabain. 4 The positive chronotropic effect of sympathetic nerve stimulation was not affected by either therapeutic or toxic concentrations of ouabain. Ouabain shifted the concentration‐chronotropic response curve for exogenous noradrenaline to the left, but did not shift the curve for tyramine. 5 Relationship between the developed tension and the rate of contraction was altered differently by ouabain and by noradrenaline. The positive inotropic effect of noradrenaline was not significantly altered by therapeutic concentrations of ouabain but it was inhibited by toxic concentrations.