Role of cyclic nucleotides and energy-rich phosphates during energetic deficiency in frog heart.
Mechanical performance, energy-rich phosphates and cyclic nucleotides of frog heart were measured during energetic deficiency and subsequent addition of adrenaline. When oxidative metabolism was inhibited by 3 mM cyanide, tension decrease was accompanied by a decrease in creatine phosphate while ATP and cyclic nucleotides did not vary significantly. After subsequent addition of adrenaline mechanical activity remained less than control value; creatine phosphate (CP) concentration was further decreased while cAMP was increased in the same proportion as when adrenaline alone was added. In the presence of cyanide, the weak inotropic effect of adrenaline is not due to an alteration of cyclic nucleotides but is rather correlated to a further decrease in energy-rich phosphates, mainly in creatine phosphate. These results suggest that creatine phosphate may control contractile activity and may be a limiting factor for inotropic interventions at least during energetic inhibition.
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D004734:Energy Metabolism; D004837:Epinephrine / Q000494:pharmacology; D009200:Myocardial Contraction; D009712:Nucleotides, Cyclic / Q000502:physiology*; D010725:Phosphocreatine / Q000502:physiology*; D011893:Rana esculenta
D009712:Nucleotides, Cyclic; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D004837:Epinephrine