[Inhibition with tetracaine of passive Ca2+ flux through the membrane of the sarcoplasmic reticulum of skeletal muscles].

The initial fast phase of Ca2+ efflux from vesicles of sarcoplasmic reticulum (SR) loaded with Ca2+ passively or in ATP-dependent process and the initial fast phase of Ca2+ influx into the SR vesicles are inhibited by 0.5 mM tetracaine. The inhibitory action of tetracaine observed both with the heavy and light SR fractions is competitive with Ca2+, decreased with varying pH from 5.8 to 7.8 and temperature from 20 degrees C to 37 degrees C. Choline chloride in the concentration of 150 mM at 37 degrees C prevents the inhibitory action of tetracaine. It is supposed that electrostatic interaction plays an essential role in tetracaine-inhibition of passive Ca2+ fluxes through the membrane.