[Free radical centers in isolated rat myocardium during perfusion with the normally oxygenated substrate-free...

EPR spectroscopy was used to measure free radical species of samples of working rat hearts freeze-clamped during their perfusion under normal conditions as well as using the substrate-free solution. It has been obtained that the transition to the substrate-free state results in decreasing of concentration of flavosemiquinones in the tissue which causes: the changes in spectral and relaxational characteristics of EPR spectra of the samples and 1,3-fold decrease of the content of free radical centers in myocardium.