dopamine

n. (C₈H₁₁NO₂) A catecholamine neurotransmitter and hormone that is important in controlling motor coordination, the pleasure pathway, and numerous mental disorders. Dopamine is metabolized into epinephrine and norepinephrine in the adrenal medulla. A lack of dopaminergic cells in the substantia nigra is associated with the development of Parkinson's disease, and many antipsychotic medications seem to work by blocking dopamine receptors.