Reference no: EM133522968

Assignment: Ion Channels

Instructions:

Consider the following questions in your responses.

Compare and contrast your initial posting with those of your peers.

A. How are they similar or how are they different?

B. What information can you add that would help support the responses of your peers?

C. Ask your peers a question for clarification about their post.

D. What most interests you about their responses?

E. Summaries at least 1 evidence based article that supports there point.

Discussion Post: Ion Channels

Part I

Compare and contrast the two different major classes of ion channels.

The two different major classes of ion channels are ligand-gated ion channels and voltage-gated ion channels, both of which are membrane proteins that play a vital role in regulating cell membrane potential and neuron communication (Stahl, 2021). Ligand-gated ion channels are also referred to as ionotropic receptors, this is because LGIC is both a receptor and channel and thus serves a dual function (Stahl, 2021). LGIC are made of amino acids and contain multiple binding sites to bind ligands such as neurotransmitters, ions, and drugs, allowing ions to either bind to a receptor or travel through the channel (Stahl, 2021). Voltage-gated ion channels are channels that mediate nerve conduction, action potential, and neurotransmitter release (Stahl, 2021). These channels are controlled by the change in ionic charge or voltage across the cell membrane (Stahl, 2021). Voltage-gated ion channels tend to be more selective, allowing the influx of only one ion at a time, whereas ligand-gated channels are less selective in nature and allow different types of ions to pass through the channel (Alberts, 2002).

Explain the difference between full agonists, partial agonists, antagonists, and inverse agonists.

An agonist is a ligand that binds to a receptor changing its state to result in a response (Stahl, 2021). The difference between full agonist, partial agonist, antagonist, and inverse agonist is that a full agonist leads to maximum signal transduction, whereas a partial agonist does not reach maximum signal transduction even with full receptor occupancy and can act as an antagonist in the presence of a full agonist (Stahl, 2021). Antagonists, on the other hand, is a ligand that binds to a receptor inhibiting its agonist-stimulated response (Stahl, 2021). Inverse agonists are ligands that when binding to a receptor cause a decrease in signal transduction, thus, their effect is the opposite of an agonist (Stahl, 2021).

Part II

Compare and contrast the two different major classes of ion channels.

To start this discussion board I would like to define what are ion channels. Ion channels are membrane proteins, which play a major role in regulating cellular excitability. There are 3 major ion channels but for this homework assignment, I will compare and contrast voltage-gated ion channels and Ligand-Gated Ion Channels (LGIC).

1. Ligand-gated ion channels open when a chemical ligand such as a neurotransmitter binds to the protein (Libretexts, 2023).

2. Voltage channels open and close in response to changes in membrane potential (Libretexts, 2023). Ion channels can be classified by how they respond to the environment.

3. Ligand-gated ion channel's permeability is greatly increased when some type of chemical ligand binds to the protein structure (Libretexts, 2023)

4. Voltage-gated channels respond to disturbances in cell membrane potential and are highly selective for specific ions such as sodium, potassium, calcium, and chloride (Ratan, 2018).

• Explain the difference between full agonists, partial agonists, antagonists, and inverse agonists.