[Blockers of the uncoupling action of caffeine on the Ca2+-transport function of sarcoplasmic reticulum membranes].
The influence of caffeine on the efficiency of Ca2+ transport in the presence of oxalate by different fractions of sarcoplasmic reticulum (SR) membranes from rabbit skeletal muscle was studied. It was shown that caffeine (5 mM) decreases 4-fold the value of the Ca/ATP ratio in terminal cisterns of the SR without having any appreciable influence on the efficiency of Ca2+ transport by the light fraction of the SR. The uncoupling effect of caffeine is completely blocked by ruthenium red and by the local anesthetics, tetracaine, procaine, and benzocaine.