- Catechol-O-Methyltransferase(COMT) > Metanephrin

- Monoaminooxidase (MAO): Metanephrin > Vanillinmandelsäure und 3-Methoxy-4-hydroxyphenylethylenglykol (MOPEG) > Urin

The concentration of adrenaline in the synaptic cleft is increased in:

• The presence of cocaine which inhibits adrenaline reuptake
• The presence of MAO inhibitors which block the metabolism of adrenaline by MAO
• The presence of noradrenaline receptor blockers and partial agonist of noradrenaline receptors.

Although COMT is also involved in the metabolism of adrenaline this occurs in the blood stream.