Synapses ensure impulses can travel in only one direction. They allow a single impulse from a single neurone to be transmitted to multiple neurones via multiple synapses or a multiple neurones can connect to the same neurone so different neurones can interact to produce a single result.Cholinergic synapses in the CNS and at neuromuscular junctions use the neurotransmitter acetyl choline. Once the action potential has been triggered, acetyl choline (ACh) is broken down by an enzyme acetylcholinesterase into choline and acetate (ethanoic acid) and reabsorbed into the pre-synaptic knob.