[Effects of local anesthetics (procaine, tetracaine) on slow calcium permeability and contraction of frog skeletal muscle fiber].

Slow inward calcium current and contraction were simultaneously recorded from isolated muscle fibres. When the release of calcium form the SR was blocked by local anaesthetics (Procaine, Tetracaine), the strict correlation between these two parameters was no longer obtained, suggesting that a calcium induced calcium release mechanism is necessary for the activation of the contractile proteins by the slow inward calcium current.