Acetylcholine

Acetylcholine is a neurotransmitter found within the central and peripheral nervous systems (including the autonomic nervous system). It is one of the neurotransmitters responsible for excitatory neuronal transmission, as well as excitatory stimulation of skeletal muscle action potentials that produce contraction. In the autonomic nervous system, it is released from post-ganglionic neurons of the parasympathetic system, including the Vagus nerve that innervates the gastrointestinal system and heart.