Norepinephrine

Norepinephrine, known as noradrenaline outside the USA, is a catecholamine and a phenethylamine with chemical formula C8H11NO3. It is released from the adrenal glands as a hormone into the blood, but it is also a neurotransmitter in the nervous system where it is released from noradrenergic neurons during synaptic transmission. It is one of the 'stress hormones' and affects parts of the human brain where attention and impulsivity are controlled. Along with epinephrine this compound effects the fight-or-flight response, activating the sympathetic nervous system to directly increase heart rate, release energy from fat, and increase muscle readiness.

Synthesis

Norepinephrine is synthesized by a series of enzymatic steps in the adrenal medulla from the amino acid tyrosine. The first reaction is the oxidation into Dihydroxyphenylalanine (L-DOPA), followed by decarboxylation into the neurotransmitter dopamine, and the final β-oxidation into norepinephrine. Norepinephrine can be further methylated to epinephrine (called adrenaline outside the USA).

Related Topics:
Adrenal medulla - Amino acid - Tyrosine - Oxidation - Dihydroxyphenylalanine (L-DOPA) - Decarboxylation - Neurotransmitter - Dopamine - Methylated - Epinephrine

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