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Ligand-gated ion channel: nicotinic acetylcholine receptor
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acetylcholine receptor

biology
Also known as: cholinergic receptor
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Ligand-gated ion channel: nicotinic acetylcholine receptor
Ligand-gated ion channel: nicotinic acetylcholine receptor The nicotinic acetylcholine receptor is an example of a ligand-gated ion channel. It is composed of five subunits arranged symmetrically around a central conducting pore. Upon binding acetylcholine, the channel opens and allows diffusion of sodium (Na+) and potassium (K+) ions through the conducting pore.

The acetylcholine receptor is a crucial component in the nervous system, particularly at the neuromuscular junction. It is a protein found on muscle cell membranes that binds to the neurotransmitter acetylcholine. This binding triggers the opening of ion channels, allowing ions to pass through the membrane and initiating a signal that can lead to muscle contraction.12

There are two main types of acetylcholine receptors: nicotinic and muscarinic. Nicotinic receptors are ion channels that open directly when acetylcholine binds, allowing for rapid signaling. Muscarinic receptors, on the other hand, indirectly affect ion channels through a secondary messenger system, resulting in slower signaling.1

A condition called myasthenia gravis involves an autoimmune attack on acetylcholine receptors, where antibodies block or reduce the number of functional receptors. This impairs the transmission of nerve impulses to muscles, leading to muscle weakness and fatigue.34

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5 Britannica Sources
  1. nervous system - Acetylcholine
  2. muscle - Release of acetylcholine from the nerve terminal
  3. muscle - Acetylcholine receptors
  4. muscle disease - Myasthenia gravis
  5. nervous system disease - Disease of the neuromuscular junction

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