Catecholamines are derivatives of the chemical dihroxyphenyl (catechol) ethylamine. The prominent naturally occurring catecholamines are dopamine, norepinephrine, and epinephrine. These agents are intrinsic neurotransmitters of the sympathetic nervous system and mediate the “fight or flight” reactions to stressful situations. Examples of sympathetic responses include: tachycardia, hypertension, bronchodilation, pupillary dilation, sweating, tremor, and liberation of fuel sources. Catecholamines also are prominent neurotransmitters in specific regions of the brain, typically being associated with pleasure, excitement, and movement.
Catecholamine synthesis involves conversion of the amino acid, Tyrosine, to dihydroxyphenylalanine (DOPA). DOPA is converted to dopamine by removal of a carboxyl group by Aromatic amino acid decarboxylase. Dopamine is both an important neurotransmitter in the brain and a precursor to norepinephrine. The latter is produced by an enzyme,...