Name: how voltage gated channels control signals
Uploaded: 2026-01-14T12:49:44.000Z
Duration: 1 min 26 s
Channel: JoVE

Voltage-gated ion channels are a class of transmembrane proteins that open and close in response to changes in the membrane potential &#8212; the voltage difference across a membrane.
These channels have a voltage-sensor domain that moves under the influence of the charge and a highly selective gated transmembrane channel for the ions' movement.
On receiving an impulse, the cell membrane depolarizes, becoming more positive. This voltage difference shifts the voltage sensors upwards, opening the gated channel, which allows ions to move down their concentration gradient.
Depending on the ion-specificity, there are four types of voltage-gated ion channels.
Voltage-gated sodium channels, abundantly found in the neurons, aid in the rapid influx of sodium ions, causing membrane depolarization.
Voltage-gated potassium channels, found in diverse cell and tissue types, allow rapid efflux of potassium ions, restoring the membrane potential.
Voltage-gated calcium channels allow the influx of calcium ions that trigger neurotransmitters' release into the synapse.
Lastly, the voltage-gated chloride channels permit chloride ions' influx and help regulate the cell volume. These are distributed in neuron

voltage-gated ion channels

Voltage-gated Ion Channels

Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of voltage-gated channels because these proteins show selective ion permeability based on ions' size and charge. For example, sodium ions, cannot pass through a potassium channel and vice versa.
Usually, these channels have an open and closed ion-conducting state. The ball and chain mechanism of action regulates the opening and closing of some classes of voltage-gated ion channels in response to the membrane potential. Here, in addition to the open and closed states, there is an inactivated state. As seen in the voltage-gated sodium channels, the inactivation gate acts as a plug or a lid that blocks the flow of sodium ions, which is the non-conducting state of the channel. Inherited or acquired defects in the sodium channel can cause abnormal neuronal firing seen in epileptic seizures, cardiac dysfunction, skeletal muscle weakness, and stiffness.
These channels have a vital role in various bodily functions. The voltage-gated calcium channels are pivotal in muscle contraction and neurotransmitter release. Potassium channels help repolarize the cell membrane after an action potential. Voltage-gated sodium channels help in membrane depolarization and propagation of the action potential.
A venomous snake, the Black mamba produces a deadly venom that blocks the voltage-gated potassium channels. This prevents the potassium ions from exiting the neuron during action potential propagation. Hence, the persistent depolarization by the sodium channels and prolonged release of the neurotransmitter acetylcholine may cause muscle hyperexcitability and convulsions.

Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the ...

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JoVE Core

Cell Biology

Unit 1

Channels and the Electrical Properties of Membranes

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KEY TERMS AND CONCEPTS

how voltage gated channels control signals

Voltage-gated ion channels control electrical signals in neurons, heart cells, and muscle cells. These transmembrane proteins open and close when the membrane potential changes. They sit in the cell membrane of electrically excitable cells and help ions move across it.

Each channel includes a voltage-sensing domain that spans the lipid bilayer. Charged residues in this sensor shift when the membrane potential changes. That movement opens the channel and allows ions to pass through.

Different voltage-gated channels let through different ions. Their selectivity depends on ion size and charge. Sodium ions cannot pass through a potassium channel, and potassium ions cannot pass through a sodium channel.

Many of these channels switch between open and closed states. Some classes also use a ball-and-chain mechanism to control gating. In voltage-gated sodium channels, an inactivation gate can act like a plug or lid. This creates an inactivated, non-conducting state that blocks sodium flow.

Defects in sodium channels can be inherited or acquired. These problems can lead to abnormal neuronal firing, epileptic seizures, cardiac dysfunction, skeletal muscle weakness, and stiffness. Other voltage-gated channels also have key jobs in the body. Calcium channels help with muscle contraction and neurotransmitter release. Potassium channels help repolarize the membrane after an action potential. Sodium channels help depolarize the membrane and spread the action potential.

A black mamba venom shows how powerful these channels are. The venom blocks voltage-gated potassium channels. As a result, potassium ions cannot leave the neuron during action potential propagation. Sodium channels keep the cell depolarized, acetylcholine release continues, and the outcome can be muscle hyperexcitability and convulsions.

How Voltage Gated Channels Control Signals

how-voltage-gated-channels-control-signals

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key terms and concepts

Learn how voltage-gated ion channels open in response to membrane potential changes and help drive nerve signals, muscle contraction, and toxin effects.

How Voltage Gated Channels Control Signals | JoVE K12

cell biology

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How Voltage Gated Channels Control Signals

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