High resolution

Module 3: Figure VOC properties

Gating properties of a typical voltage-operated channel (VOC).

When hyperpolarized, the voltage-operated channel (VOC) is closed (C). Depolarization induces an activation process and the channel opens (O), and Ca2+ enters the cytosol to form a plume of Ca2+. Upon deactivation/inactivation, the channel closes (deactivation), and the plume of Ca2+ dissipates by diffusion into the cytosol. After deactivation the channel is closed, but is in an inactive state (C*). After a variable period of inactivation (broken line), the channel recovers and is ready to open again. The plume of Ca2+ that forms around the mouth of the open channel has been visualized in cardiac cells and is called a sparklet (Module 3: Figure Ca2+ sparklet).