[The action of Cordemcura on the energy balance of the isolated rabbit heart].

The effect of Cordemcura, a new cardiotonic substance, was tested on retrograd perfused isolated rabbit hearts in comparison with equieffective doses of dopamine. The substances were applied continously via the perfusion medium in the following dosages: Cordemcura 3.34 X 10(-4) mol/l, 2.67 X 10(-3) mol/l; dopamine 3.9 X 10(-6) mol/l, 1.6 X 10(-5) mol/l). The effects of the substances were studied during normoxic and hypoxic perfusion. The heart rate was increased under normoxic perfusion of Cordemcura about 37.1% (3.34 X 10(-4) mol/l) and 17.9 (2.67 X 10(-3) mol/l). The oxygen consumption in relation to the performance of the hearts (contractility. heart rate) was increased by Cordemcura on 1.45 and 1.93 (3.34 X 10(-4) mol/l and 2.67 X 10(-3) mol/l) in the same way like by dopamine (1.30 and 2.66; 3.9 X 10(-6) mol/l and 1.6 X 10(-5) mol/l). The content of adenine nucleotides decreased in the hypoxic perfused hearts on nearly 20% of the control values. There was no difference between control, Cordemcura and dopamine treated hearts. Cordemcura increased the level of cAMP in the myocardium after 90 min of hypoxic perfusion in comparison with control hearts (control hearts 2.8 +/- 0.7 nmol/g protein; Cordemcura 4.7 +/- 0.8 nmol/g protein). In comparison to control hearts and dopamine treated hearts the hypoxic perfusion with Cordemcura resulted in a significant lower release of lactate dehydrogenase from the heart.