Neuroscience: Voltage Gated Ion Channels

Separate proteins that assemble to form a functional K+ channel, each corresponding to a domain of voltage-gated Na+ or Ca2+ channels.

K+ channels can assemble as homomers (identical subunits) or heteromers (different subunits), providing diverse functions.

K+ channels do not stay open indefinitely during sustained depolarization, but are fast activating and deactivating.

Sodium channels inactivate during sustained depolarization, preventing further current flow.

A hydrophobic loop of amino acids on the intracellular side of a sodium channel that blocks the pore when the channel is inactivated.

The process of restoring the resting membrane potential, which is necessary for sodium channels to recover from inactivation.

The ability of an ion channel to preferentially allow the passage of certain ions over others.

Size, charge and hydration energy of the ion, not just the size of the ion itself, determines passage.

Water molecules bound to ions are removed within the channel pore, enabling passage.

Transmembrane proteins that allow ions to pass through cell membranes, increasing conductance (G).

Ion channels that open and close in response to changes in membrane voltage.

Voltage-gated ion channels that are crucial for nerve impulses and are relatively late-evolving in terms of their presence on the gene level.

Voltage-gated ion channels that are involved in various cellular functions (e.g. muscle contraction).

Ion channels that allow potassium ions to pass across cell membranes.

A barrier made of lipid molecules that forms a cell membrane and acts as an electrical insulator.

The driving force for ion movement, combining the electrical potential and concentration gradients.

The ability of an ion channel to preferentially allow certain ions to pass through.

The rate at which ion channels open and close.

Part of voltage-gated ion channels that acts as the voltage sensor, detecting changes in membrane potential.

Part of the ion channel that forms an ion-filtering structure.

Repeating structures in ion channel proteins that contribute to the channel's function.

Structure within each domain that penetrates the membrane.

Structure for sodium and calcium channels; formed from only one protein.

Amino acids in the pore are structured to effectively remove water molecules from potassium ions, making them more permeable than other ions.

Channels that open or close in response to changes in the membrane potential.

A technique that allows the study of ion channels' activity with high temporal resolution.

The study of electrical activity in cells.

The membrane potential at which a regenerative increase in sodium current occurs, driving the action potential.

Channels that allow sodium ions to flow into the cell, causing depolarization.

A technique where the experimenter controls the membrane potential by injecting a precisely controlled current.

Channels responsible for the repolarization phase of the action potential.

The ability of an ion channel to preferentially allow specific ions to pass through.