What Is the Relationship Between Depolarization and Action Potential?

Depolarization is also called depolarization, which refers to a change in the polarization state of the membrane to become smaller or a change in the resting potential to a direction in which the negative value in the membrane decreases. As shown on the right, the depolarization is ab phase.

0 Depolarization Phase 0

Mainly by the rapid inward flow of Na +, the potential in the membrane rises rapidly, and the membrane potential changes from internal negative external positive to internal positive external negative, forming the rising branch of the action potential.

The depolarization process forms the ascending branch of the action potential (stage 0), and its formation mechanism is also the same as that of nerve fibers. The potential change in this period is about 120mV and the duration is 1 ~ 2ms.

Factors affecting depolarization

The stability of the cell membrane in the brain will coordinate the normal function of neurotransmission, the response is sharp, the transmission and feedback of the nerve, in addition to transmitting neurotransmitters, it also depends on voltage-dependent ion channels. Antiepileptic drugs work by blocking voltage-dependent ion channels.

The depolarization effect of the cell membrane in the brain will change the thinking activity in the brain, the limb movement of peripheral nerves, and pain sensation. This kind of effect is caused by drugs that directly affect the ion channels of cell membranes, and also by tolerance adjustment of excitement and inhibition feedback. There are many influencing factors. Drugs that can affect nerve movement and sensation will have an effect on it. It can be said that it is a nerve-specific cell function that balances and stabilizes the coordination of the body.

Blocking and reducing voltage-dependent ion channels will increase the threshold of cell membrane depolarization in the brain, making nerves less likely to excite, especially the most obvious inhibition of pain. Effectively reduce the intensity of nerve activity, make people in a relatively quiet state, the symptoms of some diseases are not obvious, and sometimes feel comfortable and relaxed. However, the actual impact on people is still great, emotions will always be low, interest will decline, the strength of thinking ability will be suppressed, and depression will be produced for a long time.

Many drugs affect cell membrane depolarization. In addition to antiepileptic drugs, anxiolytics, antidepressants and antisperm drugs, mood stabilizers, and opioid analgesics, this effect is more or less present. The anti-sperm drugs clozapine, olanzapine, and penfluridol have relatively strong inhibitory effects, which can completely suppress the manic response produced by the drug itself. Risperidone, quetiapine, is relatively weak in this kind of inhibitory effect and cannot suppress the manic effect, but it has little effect on thinking. ^[2]