 Norepinephrine is the main neurotransmitter used by the sympathetic nervous system , which consists of about two dozen sympathetic chain ganglia located next to the spinal cord , plus a set of <unk> ganglia located in the chest and abdomen . These sympathetic ganglia are connected to numerous organs , including the eyes , salivary glands , heart , lungs , liver , gallbladder , stomach , intestines , kidneys , urinary bladder , reproductive organs , muscles , skin , and adrenal glands . Sympathetic activation of the adrenal glands causes the part called the adrenal medulla to release norepinephrine into the bloodstream , from which , functioning as a hormone , it gains further access to a wide variety of tissues . 
