A: Isolated rat hindquarter preparation. The perfused muscle mass is below the dotted line. The tail is clamped off. B: Recirculating perfusion system. Heart piece is the oxygenator (1), wherein the medium is gassed (95% O2, 5% CO2) and from where it is pumped (3) up via a filter (nylon mash, 20 μm width) (2) and pH and pO2 probes (4) to attain hydrostatic pressure of 80 mm Hg (5) before entering the hindquarter (6). Intermediate sampling and pH adjustment can be carried out if necessary (7).