Flashcards in Nictotinic Acetylcholine Receptor (nAChR) Deck (7):
Pentametric Ligand-gated Receptors (GABAaR, GlyR, and 5-HT3R)
Non-selective cation channel, allows Na and other cations, strictly impermeable to anions. Results in depolarization and AP in neurons and muscle cells
ACh, Nicotine, Choline, carbachol, etc
*Needs two molecules of ACh to bind for activation
*Dissociation of ACh is slow, so channel may open and close several times before the ACh is removed
* Agonist usually remain bound until the channel closes, then they leave.
alpha-bungarotoxin (snake venom), tubocurarine (arrow head poison for South American Indians) - Competitively and irreversibly block nAChR = spastic paralysis, respiratory failure, and death.
*Synthesized antagonists include mecamylamine and memantine.
Prolonged or repeated exposure to ACh can result in desensitization and lack of response. Can also desensitize due to receptor phosphorylation by PKA or PKC
ACh usually acts as a messenger at the neuromuscular junction, results in depolarization of the muscle cell and generation of an AP.