Figure 1.

The role of acetylcholine at synapses. Choline is the main precursor for the formation of acetylcholine (Ach). Via the activity of choline acetyltransferase (ChAT), Ach is formed from choline and Acetyl-CoA. Once released at synapses, Ach binds to nicotinic or muscarinic receptors on postsynaptic neurons to regulate cholinergic signaling in different brain regions. Excess Ach at synapses is converted to choline and acetate via the activity of acetylcholine esterase (AchE). Choline is then recycled back to the presynaptic neuron via the presence of specific choline transporters such as CHT1.