Catecholamine

A catecholamine is a monoamine, an organic compound that has a catechol (benzene with two hydroxyl side groups at carbons 1 and 2) and a side-chain amine. They are derived from the amino acid tyrosine, which is sourced from diet, or from hydroxylation of phenylalanine, another amino acid. Tyrosine may be modified first into dopamine, then into norepinephrine, or even further into epinephrine before being released into blood circulation or act locally. Dopamine is a central nervous system neurotransmitter and neuromodulator produced in the brain which regulates behavior as well as motor control. Norepinephrine and epinephrine, also neurotransmitters and neuromodulators, are released by the adrenal gland with roles in activating the fight-or-flight response of the autonomic nervous system. Norepinephrine and epinephrine effect cells through binding both alpha and beta adrenergic receptors on various tissues with different affinities depending on receptor type. Dopamine binds primarily to dopamine receptors, but is also known to bind adrenergic receptors at sufficiently high concentrations.