Abstract
d-3,4-Dihydroxyphenylalanine ( d-dopa) and l-3,4-dihydroxyphenylalanine ( l-dopa) induce circling in rats with a unilateral 6-hydroxydopamine lesion of substantia nigra with similar potency. d-Dopa is not a substrate for aromatic l-amino acid decarboxylase, the enzyme which metabolizes l-dopa to dopamine. This raises the question of how d-dopa has behavioral effect. Two pathways have been suggested to result in conversion of d-dopa to l-dopa, one involving oxidation of d-dopa to dihydroxyphenylpyruvic acid (DHPPA) by d-amino acid oxidase, the other involving transamination of d-dopa to DHPPA. Here we show that sodium benzoate, an inhibitor of d-amino acid oxidase, blocks d-dopa-induced circling while having no effect on circling induced by l-dopa. The results suggest that conversion of d-dopa to l-dopa via DHPPA is highly dependent on oxidase activity and that sodium benzoate effectively inhibits this process in vivo in rat.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
