NEUROTRANSMITTER
Acetylcholine (major
transmitter of
parasympathetic
nervous system)
SOURCE
Many areas of the brain;
autonomic nervous
system
Serotonin
Brain stem,
hypothalamus, dorsal
horn of the spinal cord
Dopamine
Substantia nigra and
basal ganglia
Norepinephrine (major
transmitter of the
sympathetic nervous
system)
Brain stem,
hypothalamus,
postganglionic neurons
of the sympathetic
nervous system
Spinal cord, cerebellum,
basal ganglia, some
cortical areas
Nerve terminals in the
spine, brain stem,
thalamus and
hypothalamus, pituitary
gland
Gamma-aminobutyric
acid (GABA)
Enkephalin, endorphin
ACTION
Usually excitatory;
parasympathetic
effects sometimes
restrain (stimulation
of heart by vagal
nerve)
Restraining, helps
control mood and
sleep, inhibits pain
pathways
Usually restrains,
affects behavior
(attention, emotions)
and fine movement
Usually excitatory;
affects mood and
overall activity
Excitatory amino acid
Excitatory;
pleasurable
sensation, inhibits
pain transmission