Effects of adenosine perfusion on the metabolism and contractile activity of Rana ridibunda heart

Abstract

1. 1. The effects of adenosine were examined on the isolated perfused heart of the frog Rana ridibunda. 2. 2. Adenosine produced negative chronotropic and inotropic effects on frog ventricle in a concentration- dependent manner. 3. 3. The effects of adenosine on cardiac metabolism were also investigated by measuring the tissue content of adenine nucleotides, lactate, pyruvate, adenosine and inorganic phosphate, during adenosine perfusion. 4. 4. Adenosine had no effect on the tissue content of metabolites. 5. 5. No net synthesis of adenine nucleotides was observed during perfusion with increasing concentrations of adenosine. 6. 6. Lactate output from the heart decreased significantly with adenosine perfusion. 7. 7. Correlation of adenosine effects on cardiac muscle with the effects of hypoxia are discussed.