Cholinergic

Cholinergic (meaning having to do with acetylcholine) is a term that denotes nerve cells (receptor or synapse) for which acetylcholine serves as a neurotransmitter. Acetylcholine is the primary transmitter of nerve impulses within the parasympathetic nervous system (part of the autonomic nervous system) that contracts smooth muscles and dilates blood vessels in reaction to fear or sudden stress.