Intracellular mechanism of quinidine action on muscle contraction. A comparison between rabbit cardiac and skeletal muscle.

The mechanism of quinidine action on rabbit cardiac and skeletal muscle was examined with "functionally skinned" muscle-fiber preparations. By using these preparations we could correlate measurements of muscle tension with the effect of quinidine on the Ca2+ activation of the contractile proteins and on the Ca2+ uptake and release from the sarcoplasmic reticulum (SR).