Buchanan J W, Saito T, Gettes L S
Circ Res. 1985 May;56(5):696-703. doi: 10.1161/01.res.56.5.696.
For one-dimensional propagation, a nonlinear relationship between Vmax and conduction velocity is predicted by cable theory, and, under experimental conditions, Vmax and conduction velocity may change in opposite directions. Using standard microelectrode techniques, we have measured Vmax and conduction velocity in guinea pig papillary muscles exposed to tetrodotoxin and low sodium (agents expected primarily to decrease, directly, the rapid inward current), increased extracellular potassium (an agent which decreases the rapid inward current at least partially by inactivation mediated by depolarization of the resting membrane potential), and, over a wide range of stimulation frequencies, the antiarrhythmic drugs, quinidine, lidocaine, and procainamide. In all cases, except for the region of potassium-induced "supernormal conduction" between 5.4 and 9 mM, Vmax and conduction velocity varied as predicted by one-dimensional cable theory; that is, changes in Vmax were always proportional to changes in the square of conduction velocity. We conclude that the relationship between Vmax and conduction velocity predicted by cable theory occurs experimentally in guinea pig papillary muscle subjected to commonly used antiarrhythmic drugs and other interventions expected to reduce the sodium inward current. This relationship may be useful in applying known effects of drugs on Vmax to action potential propagation.
对于一维传播，电缆理论预测了Vmax与传导速度之间的非线性关系，并且在实验条件下，Vmax和传导速度可能会朝相反方向变化。使用标准微电极技术，我们测量了暴露于河豚毒素和低钠（预期主要直接减少快速内向电流的试剂）、细胞外钾增加（一种至少部分通过静息膜电位去极化介导的失活来减少快速内向电流的试剂）以及在广泛的刺激频率范围内的抗心律失常药物奎尼丁、利多卡因和普鲁卡因胺的豚鼠乳头肌中的Vmax和传导速度。在所有情况下，除了钾诱导的“超常传导”区域（5.4至9 mM之间）外，Vmax和传导速度的变化如一维电缆理论所预测；也就是说，Vmax的变化总是与传导速度平方的变化成比例。我们得出结论，电缆理论预测的Vmax与传导速度之间的关系在接受常用抗心律失常药物和其他预期减少钠内向电流的干预的豚鼠乳头肌中通过实验得到了验证。这种关系可能有助于将药物对Vmax的已知作用应用于动作电位传播。
