Dopamine is a catecholamine neurotransmitter (a chemical used to transmit impulses between cells), mainly in the brain and a hormone. It is also a precursor of adrenalin and noradrenaline. Catecholamines are chemically-similar small molecules that are derived from the amino acid Tyrosine. The major catecholamines are dopamine, norepinephrine, and epinephrine (adrenalin).Dopamine is present in regions of the brain that regulate movement, emotion, motivation and feelings of pleasure.