Cannabis Sativa October 12, 2016October 12, 2016 thcscience_admin Dihydroxyphenylalanine may refer to either of two chemical compounds: D-DOPA (R), 3,4-dihydroxyphenylalanine L-DOPA (S), 3,4-dihydroxyphenylalanine, a precursor of a neurotransmitter