Electron paramagnetic resonance spectroscopy on isolated rat heart: a technical note.

Spin labels have been measured directly in the isolated rat heart, perfused by the Langendorff method, using a 1500 MHz low frequency electron paramagnetic resonance spectrometer. This apparatus was previously employed to measure spin label pharmacokinetics of nitroxide sensitive to oxygen in whole mice. The heart was introduced in a resonant cavity to measure the uptake and clearance of free radicals. Various kinetic parameters were measured and are discussed, taking into account the features of the Langendorff apparatus.