H-1-NUCLEAR MAGNETIC-RESONANCE DEOXYMYOGLOBIN SIGNAL AS INDICATOR OF INTRACELLULAR OXYGENATION IN MYOCARDIUM

We report in this study that the intracellular oxygenation state is measurable with the H-1 nuclear magnetic resonance signal of the proximal histidine N(delta)H proton of deoxymyoglobin. The signal appears in a clear spectral region of the H-1 spectrum and is sensitive to various hypoxic and ischemic conditions. In perfused heart, the deoxymyoglobin's response to tissue oxygenation precedes the one reflected in the P-31 phosphocreatine or ATP signals, suggesting that oxidative energy metabolism is still sufficient even when the myoglobin is partially saturated with oxygen. Our method offers then a unique way to observe tissue oxygenation and its interaction in localized tissue region in vivo.