Drake-Holland A J, Noble M I, Pieterse M, Schouten V J, Seed W A, ter Keurs H E, Wohlfart B
J Physiol. 1983 Dec;345:75-85. doi: 10.1113/jphysiol.1983.sp014966.
The maximum rate of rise of left ventricular pressure (DP) and action potential duration (a.p.d.) were measured in closed-chest anaesthetized dogs with atrioventricular dissociation and beta-adrenergic blockade. Right ventricular stimulation was carried out with protocols consisting of a conditioning 'priming' period and a test period. When a single test stimulus was introduced at varying intervals after the priming period, DP was found to be maximal at 800-1000 ms. With this single test stimulus fixed at the optimum, DP was found to be a variable inverse function of the a.p.d. of the same beat; no positive correlation could be found between DP and a.p.d. When a second test stimulus at the optimum interval was introduced after the first, the DP (DP2) was found to be strongly dependent on that elicited by the first test stimulus (DP1); the relationship was positive, linear, independent of the method used to vary DP, and independent of whether DP1 was depressed or potentiated. The slope of the relationship was less than 1.0 and the line passed through the point where DP2 = DP1; this is the point of continuous stimulation at the optimum interval in a steady state. This result is consistent with the hypothesis that the coefficient relating DP1 to DP2, at constant a.p.d. of the first test pulse (AP1), is an index of the proportion of the activator of contraction stored during relaxation of test beat 1 which is released again on beat 2. In order to test the hypothesis that the remaining contractility depended on the action potential of test beat 1, AP1 was varied by changing the intervals between the priming stimuli. In order to determine the relationship between DP2 and AP1 it was necessary to carry out multiple regression analysis because DP2 was already known to be strongly dependent on DP1 (point 3 above), i.e. DP2 = BDP(DP1) + BAP(AP1 - D). This analysis yielded highly significant positive values for the coefficients BDP and BAP. This result is compatible with the postulate that a.p.d. influences the amount of the activator of contraction entering the intracellular store, but that this activator is not available for release to the contractile proteins until the next depolarization.
在患有房室分离且接受β-肾上腺素能阻断的开胸麻醉犬中，测量左心室压力最大上升速率（DP）和动作电位持续时间（a.p.d.）。采用包含一个条件“预激”期和一个测试期的方案进行右心室刺激。当在预激期后以不同间隔引入单个测试刺激时，发现DP在800 - 1000毫秒时最大。将此单个测试刺激固定在最佳状态时，发现DP是同一心动周期a.p.d.的可变反函数；在DP和a.p.d.之间未发现正相关。当在第一个测试刺激之后以最佳间隔引入第二个测试刺激时，发现DP（DP2）强烈依赖于第一个测试刺激（DP1）所引发的DP；这种关系是正的、线性的，与用于改变DP的方法无关，且与DP1是降低还是增强无关。该关系的斜率小于1.0，且直线经过DP2 = DP1的点；这是在稳定状态下以最佳间隔进行连续刺激的点。这一结果与以下假设一致：在第一个测试脉冲（AP1）的a.p.d.恒定的情况下，将DP1与DP2相关联的系数是在测试心动周期1的舒张期储存的收缩激活剂在心动周期2再次释放的比例指标。为了检验剩余收缩力取决于测试心动周期1的动作电位这一假设，通过改变预激刺激之间的间隔来改变AP1。为了确定DP2与AP1之间的关系，有必要进行多元回归分析，因为已知DP2强烈依赖于DP1（上述第3点），即DP2 = BDP(DP1) + BAP(AP1 - D)。该分析得出BDP和BAP系数具有高度显著的正值。这一结果与以下假设相符：a.p.d.影响进入细胞内储存库的收缩激活剂的量，但在下次去极化之前，这种激活剂无法释放到收缩蛋白中。
