Downar E, Janse M J, Durrer D
Circulation. 1977 Mar;55(3):455-62. doi: 10.1161/01.cir.55.3.455.
"Ischemic" blood was obtained in pigs from a local coronary vein on release of coronary artery occlusion. The effects of this blood on transmembrane potentials of muscle strips taken from the same heart were compared with control blood. Whereas action potentials remained stable in control blood, ischemic blood collected after more than 15 minutes of coronary occlusion produced shortening of action potential duration, reduction of resting potential, upstroke velocity and amplitude, then postrepolarization refractoriness and finally unresponsiveness. Ischemic blood collected after shorter periods of coronary occlusion produced only mild effects (shortening of action potential and postrepolarization refractoriness). These effects of ischemic blood could not be attributed to increased potassium concentration even in combination with acidosis, hypoxia and hypoglycemia. It appears that during ischemia unidentified factors are released which have potent depressant effects on the excitability of even normal myocardium.
在猪冠状动脉闭塞解除后，从局部冠状静脉获取“缺血性”血液。将这种血液对取自同一心脏的肌条跨膜电位的影响与对照血液进行比较。对照血液中动作电位保持稳定，而冠状动脉闭塞超过15分钟后收集的缺血性血液会导致动作电位时程缩短、静息电位降低、去极化速度和幅度减小，继而出现复极后不应期，最终导致无反应性。冠状动脉闭塞较短时间后收集的缺血性血液仅产生轻微影响（动作电位缩短和复极后不应期）。即使合并酸中毒、缺氧和低血糖，缺血性血液的这些影响也不能归因于钾浓度升高。看来在缺血期间会释放一些不明因素，这些因素对即使是正常心肌的兴奋性也有强大的抑制作用。
