Answer:
Calcium; voltage-gated calcium channels
Step-by-step explanation:
Voltage-dependent calcium channels represent a group of voltage-gated ion channels and they are recognized to be primary mediators of calcium entry induced by depolarization. These channels are localized in the membrane of excitable cells such as, for example, neuron cells. The potential difference across the membrane of neuron cells without physiological activity is named resting membrane potential. When there is no action potential, voltage-dependent calcium channels are normally closed.