The enzyme is supposed to regulate monoamine, which are neurotransmitters :
* Catecholamines:
o Dopamine (DA)
o Norepinephrine (NE) (noradrenaline, NA)
o Epinephrine (Epi) (adrenaline)
* Serotonin (5-HT)
* Melatonin
* Histamine
* Thyronamines, a new group of compounds derived from thyroid hormones
* Trace amines:
o ?-Phenylethylamine (PEA, ?-PEA)
o Tyramine
o Tryptamine
I just don't see what the link is with therobromine since it does not share any chemical structure with the above listed substances. I've searched for relations with methylxanthines (even if they aren't neurotransmitters), and found nothing...