[Effect of anoxia on energy supply and isotonic work performance in the myocardium of the frog].
To investigate correlations between energy supply and mechanical work in the frog's myocardium in true anoxia, the stroke volume, systolic and diastolic volumes and the parameters of velocity of contraction and relaxation of frog hearts were compared to the levels of high energy phosphates and the delivery of lactate. During perfusion with N2 saturated Ringer solution, stroke volume, systolic contractility and diastolic relaxation decrease till a contracture. High preload produces a dilatation growing up to the contracture after retarded and weakened relaxation. The ATP-content decreases during the first quarter of the experiment to 60%. CP decreases continuously to 15%, ADP and AMP remain constant. There is a production of lactate increasing considerably with the onset of contracture. The measured glycolysis is not sufficient for production of mechanical work. The effect of anoxia on the action potential and the reduction of the sequestration of Ca++ and of the break of actomyosin bridges following the decrease of ATP are considered as causing the series of the mechanical events.
D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001001:Anura; D004734:Energy Metabolism; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D000860:Hypoxia / Q000503:physiopathology*; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*
D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate
Die Wirkung von Anoxie auf Energiebereitstellung und isotonische Arbeitsleistung des Froschherzventrikels