Phenytoin (sodium channel blocker) and ethosuximide (calcium channel blocker) are anti-seizure drugs that stop seizures from happening. These drugs work by inhibiting electrical impulses (action potentials) from occurring. Explain the importance of sodium and calcium channels on a neuron and and the reasons why action potentials do not occur when these channels are inhibited. Be sure to include the phases of an action potential, the channels involved, and the importance of an action potential.

Explanation:

Action potential

It is the potential or power or electrical energy required to generate impulses and provides communication between the neurons is called action potential. Normally cell membrane consists of potential is called resting membrane potential() -70mV. The action potential is due to exchange of different ions across the membrane.

Phases of the action potential in a neuron are

i. Depolarization- it is caused by the influx of sodium and calcium ions through the opening of voltage-gated sodium and calcium channels. sodium ion influx is rapid than the calcium ions membrane potential -70mV to +30mV.

ii. Repolarization - It causes the efflux of potassium ions into the cell through the opening of potassium channels. the membrane returning to resting membrane potential.

iii. After- Hyper polarization - in this stage the potassium channels remain open and causes re polarization and comes to normal membrane potential.

The generation of impulses(depolarization) in neuron mainly depends on influx sodium and calcium ions without these ions, no action potential developed and neuron firing does not occur.

If the drugs inhibit these channels, no depolarization, no action potential, no neuronal firing or communication.

The channels involved in an action potential are voltage-gated sodium channels, potassium channels, and calcium channels.

The action potential is required for transmission of information one are to another area in the body.

The responses to different stimuli is due to action potential.

answer; curiosity;

answer; bona fide occupational qualification; (bfoq);