Acetylcholine synthesis and inactivation

The Synthesis of acetylcholine (ACh) from acetyl CoA and choline is catalyzed by choline acetyl transferase (ChAT), a cytoplasmic enzyme. The Acetyl CoA is derived from glycolysis and should be transported out of the mitochondria of cholinergic neurons. This supply of acetyl CoA, instead of ChAT activity, is thought to be limiting rate for ACh synthesis. The Cholinergic neurons states a Na⁺-dependent choline transporter that is saturated at plasma choline concentrations and is answerable for the uptake of choline into the neurons. The ACh is loaded into vesicles by a transporter which is related to the vesicular monoamine transporters.

The synaptic action of ACh is completed by its hydrolysis in the cleft to choline and acetate by acetylcholinesterase (AChE). The choline liberated is recovered by the Na+-dependent choline transporter.