Bosker H, Drake-Holland A J, ter Keurs H E, Noble M I, Passingham J E, Pepper J R, Main M J, Wanless R B
Cardiovasc Res. 1985 Nov;19(11):674-8. doi: 10.1093/cvr/19.11.674.
The action potential duration (APD) was measured using an Ag-AgCl electrode, in open chest anaesthetised dogs (n = 8) and puppies, 4 to 6 months old (n = 8), with complete atrio-ventricular dissociation and beta-adrenergic blockade. They were paced in the control period at a frequency of 120 beats . min-1. Both adults and puppies showed maximum action potential duration at a test pulse interval of over 700 ms. Below this the adult dogs showed a progressive shortening of the action potential duration (mean APD 81.5% at 200 ms). In contrast, the puppies showed much less shortening (91% at 200 ms; p less than 0.001). Measurements of Na+, K+-ATPase activity by the Rb uptake method gave values of 13.4 +/- 1.3 (puppies, n = 4) and 6.1 +/- 1.1 (adults, n = 6). These results may be consistent with the idea of a greater influx and efflux of sodium in the myocardial cells of the puppy compared with the adult dog.
在开胸麻醉的犬（n = 8）和4至6月龄幼犬（n = 8）中，使用银 - 氯化银电极测量动作电位持续时间（APD），这些动物存在完全房室分离和β - 肾上腺素能阻滞。在对照期以120次/分钟的频率进行起搏。成年犬和幼犬在测试脉冲间隔超过700毫秒时均显示出最大动作电位持续时间。低于此值时，成年犬的动作电位持续时间逐渐缩短（在200毫秒时平均APD为81.5%）。相比之下，幼犬的缩短程度要小得多（在200毫秒时为91%；p < 0.001）。通过铷摄取法测量的Na +，K + - ATP酶活性值，幼犬（n = 4）为13.4±1.3，成年犬（n = 6）为6.1±1.1。这些结果可能与幼犬心肌细胞中钠的流入和流出比成年犬更多的观点一致。
