High Yield Acetylcholine and Ach Receptors

A summary of high yield clinical topics related to acetylcholine chemistry and acetylcholine receptors.

Myasthenia Gravis

In myasthenia gravis there are antibodies to nicotinic Ach receptors, so over the course of a day the nAchR in the NMJ get blocked and movement becomes sluggish.

Acetylcholinesterase inhibitors, that slow the degradation of Ach therefore increasing the Ach concentration in at the NMJ, is a good treatment. Thymectomy is often curative, although the mechanism of cure is not well understood.

Botulinum Toxin (botox)

Ach is the neurotransmitter at the NMJ, so toxins that block vesicle fusion (botulinum toxin) prevent Ach release so effectively paralyze the muscle. This is useful therapeutically for blepharospasm (spasm of the eyelid), strabismus, spasmodic torticollis, drooling associated with cerebral palsy, and more recently, for cosmetic wrinkle reduction.


Pilocarpine, a muscarinic agonist, is used to reduced intraocular pressure in glaucoma.

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About the Author: Naoum P. Issa MD PhD