乙酰胆碱(ACh)是一个分子功能n the brain and body of many types of animals, including humans, as aneurotransmitter. Those parts of the body that use or are affected by acetylcholine are referred to as cholinergic, while substances that interfere with acetylcholine activity are called anticholinergics.

ACh is used at the neuromuscular junction in the skeletal muscle and also in theautonomic nervous systemto control the smooth and cardiac muscle, both as an internal transmitter for thesympathetic nervous systemand as the final product released by theparasympathetic nervous system.

Like many other biologically active substances, acetylcholine exerts its effects by binding to and activating receptors located on the surface of cells. There are two main classes of acetylcholine receptor, nicotinic and muscarinic.

ACh is broken down by the acetylcholinesterase, which is found in the chemical synapses of the cholinergic type, where its activity serves to terminate the synaptic transmission.