D-DOPA is an enantiomer of the dopamine precursor L-DOPA . It can be converted to L-DOPAviasequential oxidation and transamination, which are mediated by D-amino acid oxidase (DAAO) and DOPA transaminase, respectively, in rat kidney homogenates.¹It reduces the number of dopaminergic neurons in primary rat embryonic mesencephalic cultures in a concentration-dependent manner.²Intraventricular administration of D-DOPA (200 ?g/animal) increases striatal dopamine levels in rats.³D-DOPA (20 mg/kg, i.p.) induces contralateral turns in a rat model of Parkinson's disease induced by 6-OHDA .⁴

1.Wu, M., Zhou, X.-J., Konno, R., et al.D-dopa is unidirectionally converted to L-dopa by D-amino acid oxidase, followed by dopa transaminaseClin. Exp. Pharmacol. Physiol.33(11)1042-1046(2006) 2.Ling, Z.-D., Pieri, S.C., and Carvey, P.M.Comparison of the neurotoxicity of dihydroxyphenylalanine stereoisomers in cultured dopamine neuronsClin. Neuropharmacol.19(4)360-365(1996) 3.Karoum, F., Freed, W.J., Chuang, L.-W., et al.D-dopa and L-dopa similarly elevate brain dopamine and produce turning behavior in ratsBrain Res.440(1)190-194(1988) 4.Moses, J., Siddiqui, A., and Silverman, P.B.Sodium benzoate differentially blocks circling induced by D-and L-dopa in the hemi-parkinsonian ratNeurosci. Lett.218(3)145-148(1996)