Voltage sensor current, SR Ca release, and Ca channel current during trains of action potential-like depolarizations of skeletal muscle fibers.

In skeletal muscle, Ca 1.1 serves as the voltage sensor for both excitation-contraction coupling (ECC) and L-type Ca channel activation. We have recently adapted the technique of action potential (AP) voltage clamp (APVC) to monitor the current generated by the movement of intramembrane voltage sensors (I ) during single imposed transverse tubular AP-like depolarization waveforms (I ).