Use of perfused isolated muscle, as studied by (31)P NMR, to investigate metabolism and post-mortem changes.

An experimental system was designed to study as independently as possible the effects of various in-vivo or post-mortem factors susceptible to influence muscle metabolism. This system was made up of an NMR probe, a physiological stimulator, a perfusion system and a force monitoring device. Rabbit muscles were isolated and perfused with bovine red cells, then put into the NMR probe to follow the evolution of pH and phosphorylated compounds. It was possible to keep muscle metabolism stable for 2 h. Death was simulated by stopping the perfusion which allowed post-mortem changes to be followed. The effects of adrenaline perfusion or of a 5 s tetanus on some traits of metabolism and on changes following muscle death were studied. Tetanus immediately before perfusion was stopped accelerated changes in pH and in phosphocreatine and ATP contents; adrenaline perfusion during 30 min before perfusion was stopped had little effect on these traits.