L-3,4-dihydroxyphenylalanine (L-DOPA)

L-DOPA, also known as levodopa or L-3,4-dihydroxyphenylalanine, is an amino acid derivative and the direct biosynthetic precursor to the neurotransmitter dopamine. It is synthesized from L-tyrosine by tyrosine hydroxylase and then converted into dopamine by aromatic L-amino acid decarboxylase (AADC). L-DOPA can cross the blood-brain barrier while dopamine cannot, making it the principal medicinal agent for replenishing brain dopamine in Parkinson’s disease and other dopamine-deficiency disorders. In addition to being a metabolic precursor, L-DOPA is proposed to have direct neuromodulatory activity and may bind specific receptors such as GPR143. Its long-term administration is associated with complications such as motor fluctuations and dyskinesias.

Other names

LevodopaL-DopaL-3,4-dihydroxyphenylalanine

Crosses blood-brain barrier, converted to dopamine by AADC; Restores dopamine levels to ameliorate motor symptoms in Parkinson’s disease; May have direct neuromodulatory/transmitter actions apart from conversion.