Figure 6).

Representative ³¹P-magnetic resonance spectra obtained from the four groups after 15 min of sustained ischemia (compared with the baseline study). Each spectrum is an accumulation of 90 free induction decays taken during peak systolic and end-inspiratory phases over 5 min. In the preconditioning (PC) group, phosphocreatine (Pcr) and ATP were preserved, and the chemical shift of the major inorganic phosphate (Pi) peak was slight, as shown by arrowheads. Note the loss of this beneficial effect of PC in the PC plus N-2-mercaptopropionyl glycine (MPG) group