Blood flow and tissue -pO2 in the trained and untrained gastrocnemius muscle of the anesthetized guinea pig.

In 10 guinea pigs the gastrocnemius muscles on one side were tenotomised. By the tenotomy the daily work load of the gastorcnemius muscle was lowered in the operated leg ("untrained muscles") and increased in the control leg ("trained muscles"). Before and several weeks after the operation blood flow was measured in the lower legs (by segmental plethysmography) and oxygen pressure was measured in the gastrocnemius muscles (by micro-Pt-electrodes) of the anesthetized animals. 4 to 6 weeks after the operation statistically significant differences between the two extermities were noted: In the operated leg the mean pO2-value was 33%lower (P is less than 0.001) and the mean blood flow value 46% higher (P is less than 0.001). These differences could be explained by a reduced number of perfused capillaries in the untrained muscles (= non uniform blood flow distribution).