What Are Potassium Channels?

Potassium ion channel refers to a channel that allows potassium ions to pass through the plasma membrane and prevents other ions, especially sodium ions, from passing through.

Potassium channel

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Potassium ion channel refers to a channel that allows potassium ions to pass through the plasma membrane and prevents other ions, especially sodium ions, from passing through.

Ion channels of biomembrane are channels for the passive transport of various inorganic ions across the membrane. There are two modes of transmembrane transport of biological ions for inorganic ions: passive transport (cis ion concentration gradient) and active transport (reverse ion concentration gradient). The path of passive transportation is called ion channel, and the ion carrier of active transportation is called ion pump. Biofilm's permeability to ions is closely related to various life activities.

Chinese name

Potassium channel

Foreign name

Potassium ion channel

Ion channel

Is the basic element of signal transmission in the nervous system

Japanese name

Potassium channel

All living cells are surrounded by a membrane, which isolates the liquid world inside the cell from the external environment. The membrane quality can effectively prevent small ions from passing (and the same is true for large molecules such as proteins and nucleic acids), so it is a cell Provides new opportunities: rapid signal transmission can be performed based on the difference in ion concentration. First, the cell can increase the potassium concentration inside it; then, as certain channels on the transient stimulation membrane are opened immediately, potassium ions are released, It causes a huge change in the potassium concentration of the entire cell, which results in signal transmission. This process is found in various cell forms, such as bacterial cells, plant cells and animal cells. There are two examples of the role of ion channels: muscle contraction (Initiated by calcium ion release) and neuronal signaling (including a complex sodium-potassium ion exchange).

Ion channels are the basic components of signalling in the nervous system. When you smell a flower, you know it's a rose; or when your hand touches something hot, you immediately retract your hand. This is because The sensory organs of the human nasal cavity and hands transmit signals from the nerves to the brain through ion release, which is done by the brain to respond appropriately. Among them, nerve cells take in a large amount of potassium ions and selectively pump out sodium ions As a result, a signal is transmitted, and a potential difference is generated inside and outside the membrane. In order to transmit the signal, the nerve cell first opens the sodium ion channel, takes in sodium ions, and reduces the potential difference between the inside and the outside of the membrane. Then it opens the potassium ion channel and expels potassium ions. The membrane potential is restored to a resting level. After that, sodium and potassium ions are redistributed inside and outside the cell through other channels and pumps. Due to this clever design, these channels are very sensitive to membrane potential, and the channel will open with a slight change. Therefore, the ion flow generated when a channel of a nerve cell is opened will instantly trigger the opening of the downstream channel of the plasma membrane. As a result, the signal is transmitted through the channel opening and propagates along the wave. The plasma membrane spreads quickly to the end.

The specificity of the potassium ion channel allows the passage of potassium ions through the plasma membrane, while impeding the permeability of other ions, especially sodium ions. These channels generally consist of two parts: one is the channel region, and he selects and allows potassium ions to pass While blocking sodium ions; the other part is a gated switch that switches channels based on signals in the environment.The structure is shown in protein library number 1bl8, showing the channel region part of a potassium channel of a bacterium. Source of transmembrane protein, forming a selective hole in the center. Potassium ions (green) pass freely at a rate of 100 million per second. Due to specific selectivity, only one sodium is allowed for every 10,000 potassium ions passing through Ions pass. You can see how the channel structure completes the specific selection in the crystal map on the next page.