Help with the question please Some voltage-gated channels can inactivate while s
ID: 164445 • Letter: H
Question
Help with the question please
Some voltage-gated channels can inactivate while some ligand-gated channels can desensitize. Describe the difference between inactivation and desensitization of an ion channel. Give one concrete example of a channel that is known to inactivate (besides the typical action potential Na^+ channel discussed in class) and one concrete example of a channel that is known to desensitize (besides the glutamate channel discussed in class). You will need to search the literature.Explanation / Answer
Answer:
2. a. Inactivation and desensitization are the terms typically associated with mechanisms in voltage-gated and ligand-gated ion channels, respectively.
When a voltage-gated ion channel enters a state in which activation does not occur even though the activation current is present, it is called inactivation.
Desensitization is the unresponsiveness of ligand-gated ion channels caused due to prolonged activation by a chemical stimuli. (Example: blocking the channels with a toxin)
b. Example of a voltage-gated ion channel known to inactivate is Voltage Gated Calcium Channel.
The fast inactivation of voltage-dependent calcium channels is an important, intrinsic regulatory mechanism that helps to precisely control the amount of calcium entering excitable cells during membrane depolarizations.
Example of a ligand-gated ion channel known to desensitize is TRPV1 (Transient Receptor Potential Vanilloid) ion channel.
Capsaicin and other vanilloids selectively excite and subsequently desensitize pain-conducting nerve fibers (nociceptors) and this process contributes to the analgesic effects of these compounds. Such a desensitization process is triggered by the activation of the TRPV1 receptor channels (TRPV1) that open their cationic pores, permeable to sodium, potassium and calcium ions.