The Effect of Succinylcholine on Canine Gastrocnemius‐muscle Oxygen Consumption

In dogs anesthetized with halothane and maintained at 37 C, gastroenemius-plantaris muscle Vo2. increased with intravenously administered succinylcholine (SCb). With continuous paralyzing amounts of SCh, the increase in Vo2 peaked at 50 to GO per cent in the first 20 minutes and was sustained thereafter at approximately 20 per cent above control. Cilia mine in paralyzing amounts prevented the initial peak increase but was with-out effect on the sustained increase. The peak increase is believed to result from the action of SCh at the motor end-plate, leading to generation of an action potential and contraction of the muscle fiber, and the sustained increase to result from an increase in the energy requirements that arises out of cither an alteration in the normal activity of resting muscle or the presence in the muscle fiber of an agent causing sarcomeric oscillation.