The principal neurotransmitters of the autonomic nervous system.and their actions.

Type of neuron	Principal neurotransmitter	Actions of transmitter	
Preganglionic sympathetic
(presynaptic terminals in ganglion)	Acetylcholine	Stimulates neurons in a  sympathetic ganglion when it binds to nicotinic receptors 	
Preganglionic parasympathetic (presynaptic terminals in ganglion)	Acetylcholine	Stimulates neurons in a parasympathetic ganglion when it binds to nicotinic receptors 	
Sympathetic ganglion (presynaptic terminals on smooth muscle, cardiac muscle or secretory cells)	Noradrenaline

Acetylcholine	Different actions on cells with either alpha or beta receptors.
Alpha: Vasoconstriction in skin and internal organs; arrection or hairs; contraction of sphincters in G-I tract; dilation of pupil.
Beta: Vasodilation in muscle; increased heart rate and stroke volume; dilation of bronchioles; reduced propulsion in G-I tract.

Stimulation of ordinary (eccrine) sweat glands (muscarinic receptors)
	
Paraympathetic ganglion (presynaptic terminals on smooth muscle, cardiac muscle, or secretory cells)	Acetylcholine	Actions of all cells innervated by parasympathetic ganglia, by binding to muscarinic receptors.

Cranial outflow: 
  III (ciliary ganglion): Constriction of pupil and accommodation of lens.
 VII (pterygopalatine and submandibular ganglia): Secretion from lacrimal, sublingual and submandibular glands.
  IX (otic ganglion): Secretion from parotid gland.
   X: (cardiac ganglia): reduced heart rate;
        (ganglia associated with respiratory tract): constriction of bronchioles;
        (ganglia of the enteric nervous system): secretion of stomach acid and pancreatic juice; increased propulsion and relaxation of sphincters in G-I tract.
  
Sacral outflow (ganglia in the pelvic plexuses):
 Contraction of detrusor muscle (bladder); vasodilation in erectile tissue of genitalia.