What Is a Resting Neuron?

When living tissue cells such as neurons and muscle cells are at rest, the potential inside the membrane is negative compared to outside the membrane, with a difference of 70-90mV, which is called polarization. This potential difference between the inside and outside of the membrane is called the resting potential or membrane potential. ^[1]

Resting potential generation mechanism

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When living tissue cells such as neurons and muscle cells are at rest, the potential inside the membrane is negative compared to outside the membrane, with a difference of 70-90mV, which is called polarization. This potential difference between the inside and outside of the membrane is called the resting potential or membrane potential. ^[1]

Resting potential refers to the positive and negative potential difference that exists on both sides of a cell when it is quiet. There are two important conditions for this, one is the imbalanced distribution of ions on both sides of the membrane, and the other is the difference in membrane permeability to ions at rest.

The intracellular K concentration and the negatively charged protein concentration are both greater than the extracellular concentration (and the extracellular Na and Cl concentrations are greater than the intracellular concentration), but because the cell membrane only has a relatively high permeability to K at rest, the difference between the K and K concentration Cells move outside the cell, and negatively charged protein ions in the membrane cannot penetrate the cell, hindering K outflow. Then the K ions move out and the inside of the membrane becomes negative and the outside of the membrane becomes positive. On the one hand, the state of positive and negative on the outside can increase with the outward movement of K. On the other hand, the positive and negative of the outward movement formed by K will hinder the outward movement of K. In the end, a state where K is shifted out (due to the difference in concentration) and hindered K is shifted out (due to the difference in potential) is reached. This is the membrane potential called the K equilibrium potential. , Which can be calculated by Nernst formula:

The resting potential is the result of the combined action of K and Na, and can be calculated by the Goldman equation:

In the formula, Vm represents the membrane potential, E K and E Na represent the equilibrium potential of K and Na, respectively, and g K and g Na represent the conductance of K and Na, respectively. At the resting potential, since g K >> g Na, the membrane potential is very close to the equilibrium potential of K, but it is also biased towards the equilibrium potential of Na.

(Explanation) When the nerve cell is at rest, the k + channel is open (Na + channel is closed). At this time, k + will move from the inside of the membrane with a high concentration to the outside of the membrane with a low concentration. The generation of positive electricity outside the membrane prevents the continuous outflow of k + in the membrane, so that the membrane potential no longer changes. At this time, the membrane potential is called the resting potential.