acetylcholine

American  

[uh-seet-l-koh-leen, uh-set-] / əˌsit lˈkoʊ lin, əˌsɛt- /

noun

1. Biochemistry. the acetic acid ester of choline, C 7 H 17 NO 3 , released and hydrolyzed during nerve conduction and causing muscle action by transmitting nerve impulses across synapses.

2. Pharmacology. this substance used in its chloride form in eye surgery. ACh

---

acetylcholine British  

/ -lɪn, ˌæsɪtaɪlˈkəʊliːn /

noun

1. a chemical substance secreted at the ends of many nerve fibres, esp in the autonomic nervous system, and responsible for the transmission of nervous impulses. Formula: CH 3 CO 2 (CH 2 ) 2 N (CH 3 ) 3 ⁺

---

acetylcholine Scientific  

/ ə-sēt′l-kō′lēn′ /

1. A substance that is released at the junction between neurons and skeletal muscle fibers, at the nerve endings of the parasympathetic nervous system, and across synapses in the central nervous system, where it acts as a neurotransmitter. Chemical formula: C ₇ H ₁₆ NO ₂ .

---

Other Word Forms

• acetylcholinic adjective

Etymology

Origin of acetylcholine

First recorded in 1905–10; acetyl + choline

Example Sentences

In Alzheimer's disease, acetylcholine levels are already reduced, which contributes to memory loss and cognitive decline.

From Science Daily • Feb. 8, 2026

What we know now is that nicotine is a chemical compound that acts on receptors in the brain called nicotinic acetylcholine receptors, or nAChRs.

From Slate • Jun. 11, 2025

Those receptors usually respond to acetylcholine, a neurotransmitter involved in everything from muscle activation to attention.

From Slate • Jun. 11, 2025

Too much acetylcholine in lab animals leads to muscle cramps, weakness, blurry vision, and paralysis.

From Science Magazine • Nov. 29, 2023

By this means a precise balance is struck and the body never builds up a dangerous amount of acetylcholine.

From "Silent Spring" by Rachel Carson