Catecholamines are a group of biogenic amines primarily synthesized in the adrenal medulla or the cells of the sympathetic nervous system from the amino acid tyrosine through the intermediate product dopamine. Dopamine, adrenaline (epinephrine) and noradrenaline (norepinephrine) are members of this group. In response to the physical and emotional stress, catecholamines are released into the bloodstream and act as important hormones and neurotransmitters.