Muscle PO2 in the initial phase of increased local oxygen demand (rhythmical muscle contraction) in rats with portacaval shunt (PCA).

The influence of a hyperdynamic syndrome caused by PCA on PO2 distribution in skeletal muscle of rats during the initial phase of muscle activity was examined. Rhythmical muscle contraction of the m. biceps femoris was induced by direct electrical stimulation. Tissue PO2 of the contracting muscle was recorded continuously from the start of the 210 s-long activity period up to 140 s after the last contraction using a multiwire surface electrode. In comparison with controls no different behaviour of mean muscle PO2 in the initial phase of contraction was found. After muscle activity mean PO2 decreased to a lower level in rats with PCA than in controls. This might be a further indication of the disturbing influence of a hyperdynamic syndrome on the regulating mechanisms of the microcirculation.