The Relationship between Initial Creatine Phosphate Breakdown and Recovery Oxygen Consumption for a Single Isometric Tetanus of the Frog Sartorius Muscle at 20~

A previous paper (Mahler, M. 1978. J. Gen. Physiol. 71:559-580) describes the t ime-course o f the suprabasal rate of oxygen consumption (AQo~) in the sartorius muscle o fR . p/p/ens after isometric tetani of 0.1-1.0 s at 20~ To test whether these were the responses to impulse changes in the rate of ATP hydrolysis, we compared the total suprabasal oxygen consumption dur ing recovery (A[O~]) with the amount of ATP hydrolyzed dur ing a contraction, measured indirectly as the decrease in creatine phosphate (A[CP]0). I f suprabasal ATP hydrolysis dur ing recovery is negligible in comparison with that dur ing contraction, A[CP]0/A[02] should approximate the P :02 rado for oxidative metabolism, which has an expected value of 6.1-6.5. We found: