Acetylcholine (ACh) functions as a neurotransmitter in both the central and peripheral nervous systems of all vertebrates, and is the principal neurotransmitter used at the neuromuscular junction. This neurotransmitter is synthesized from choline (Ch) and acetyl-coenzyme A by choline acetyltransferase (ChAT). For this pathway choline is required, which neurons acquire through high-affinity choline transporters (ChTs). ChT have been found on the presynaptic membrane but also on ACh containing synaptic vesicles.