Siess M, Stieler K, Englert R, Teutsch I
Institute of Pharmacology, University of Tuebingen, FRG.
Bratisl Lek Listy. 1991 Jan;92(1):9-23.
Auxotonic work/beat and contraction curves were recorded from left guinea pig atria stimulated with 0.5 Hz at 5 mN preload in K.H.-solution + 15 mmol/l glucose, 95% O2 or N2 + 5% CO2, 30 degrees C. Eight common parameters of the contraction curve were calculated simultaneously in a computerized system as reported previously (Englert, R. et al., N.-Arch. of Pharmacol., 337, Suppl. R. 60, 1988). By increased anaerobic glycolysis anoxia reduced contractile activity which after 30 min reached a plateau of approximately 50% of the initial aerobic value during approximately 2 hours. At reoxygenation the contraction force increased with a first peak overshooting 50% of the initial aerobic value after 5-10 min, to decline during the following 10-15 min to a plateau slightly below the initial aerobic value. Several parameters exhibited characteristic changes during anoxia and reoxygenation: during the first minutes of reoxygenation in the ascension of the first peak the 'time to peak force', the 'relaxation time' and the 'area under the contraction curve', especially the part below the relaxation, were strongly but only transiently increased. Positive and negative inotropic agents influencing cytosolic free Ca2+ in different ways applied 15 minutes before reoxygenation indicated that the observed overshooting peak of force and the prolongation of contracation duration after reoxygenation were presumably due to transiently disturbed intracellular Ca2+ redistribution in sarcoplasmic reticulum and mitochondria during the restitution of high energy phosphates.
在30℃下，用0.5Hz的频率、5mN的前负荷刺激豚鼠左心房，在含有15mmol/L葡萄糖的K.H.溶液、95%O₂或N₂ + 5%CO₂的环境中记录辅助张力功/搏动和收缩曲线。如先前报道（Englert, R.等人，《药理学文献》，337，增刊R. 60，1988），在计算机系统中同时计算收缩曲线的八个常见参数。缺氧通过增加无氧糖酵解降低收缩活性，30分钟后在约2小时内达到初始有氧值的约50%的平台期。复氧时，收缩力在5 - 10分钟后增加，第一个峰值超过初始有氧值的50%，随后在接下来的10 - 15分钟内下降至略低于初始有氧值的平台期。在缺氧和复氧过程中，几个参数表现出特征性变化：在复氧初期第一个峰值上升过程中，“达到峰值力的时间”、“舒张时间”和“收缩曲线下面积”，尤其是舒张以下部分，强烈但只是短暂增加。在复氧前15分钟应用以不同方式影响胞质游离Ca²⁺的正性和负性肌力药物表明，复氧后观察到的力的过冲峰值和收缩持续时间的延长可能是由于在高能磷酸盐恢复过程中，肌浆网和线粒体中细胞内Ca²⁺再分布暂时紊乱所致。
