Acetylcholine receptors and the autonomic nervous system

Acethylcholine acts on central and peripheral nervous systems ( the latter is divided into somatic and autonomic). The autonomic nervous system (ANS)  exerts its actions through its two antagonic branches: sympathetic ( adrenergic) and parasympathetic (cholinergic).

Looking the diagram below we can see that both sympathetic and parasympathetic branches are modulated at the preganglionic level by the neurotransmitter acetylcholine. This molecule binds nicotinic receptors at the autonomic ganglia to trigger the release of norepinephrine (if a sympathetic synapse is stimulated) or acetylcholine that binds to tissue muscarinic receptors, which will produce a parasympathetic or cholinergic response.