Notes: L-DOPA (Item No. 13248) is a metabolic precursor of dopamine that is capable of crossing the blood brain barrier to act as a dopamine D1 receptor agonist. It is produced from L-tyrosine by trysosine hydroxylase. In the brain, L-DOPA is converted to dopamine by the enzyme aromatic L-amino acid decarboxylase. It is conventionally used to increase dopamine concentrations in the brain as a treatment for Parkinson’s disease and stroke recovery.{17819} L-DOPA methyl ester is a neutral derivative of L-DOPA formulated for increased solubility compared to the parent compound.{26614}