[J] [PINEAL: BIOPTERIN] Treatment with sapropterin dihydrochloride, a synthetic form of tetrahydrobiopterin (BH4)

'Disorders of tetrahydrobiopterin metabolism and their treatment.'

www.ncbi.nlm.nih.gov/pubmed/12003346

https://en.wikipedia.org/wiki/Tetrahydrobiopterin

"Tetrahydrobiopterin deficiency also disrupts the levels of certain neurotransmitters in the brain, which affects the function of the central nervous system (CNS), and dysregulation of the nitric oxide cycle leads to a buildup of peroxynitrite, an inflammatory oxidant that further degrades BH4 and perpetuates a state of inflammation."

https://en.wikipedia.org/wiki/Tetrahydrobiopterin_deficiency

https://en.wikipedia.org/wiki/Biopterin