Ion channels are membrane proteins that form a pore which allows ions to pass through. They are present in the membranes of all excitable cells, such as neurons, muscle cells, and some endocrine cells.

The functions of the ion channels include establishing a restingmembrane potential, shapingaction potentialsand other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume.

The most common ion channels are thevoltage-gated sodiumand the电压门控钾ones.