Phosphorus NMR studies on perfused heart

Phosphorus nuclear magnetic resonance measurements at 129MHz have been made on small beating rat hearts, perfused by the Langendorff technique. Good spectra, giving the levels of ATP, creatine phosphate and inorganic phosphate can be collected in as little as 10–20min and the heart can be maintained in a steady state in the spectrometer for at least 5 hours. In a good preparation, the ratios of the β-phosphate of ATP to creatine phosphate and inorganic phosphate are 1:1.8:1.8 which compare well with the data obtained by analyzing a freeze-clamped extract by NMR. The recovery of metabolites, after the induction of global ischaemia, has been followed.