Striatal L-dopa metabolism studied in vivo in rats with nigrostriatal lesions

T. Brannan, A. Bhardwaj, J. Martinez-Tica, J. Weinberger, M. Yahr

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

We have used cerebral dialysis to monitor striatal metabolism of exogenously administered L-dopa (L-dihydroxyphenylalanine) in rats with unilateral lesions of the substantia nigra. The concentration of extracellular dopamine (DA) increased in both striata following L-dopa administration but the increase was markedly attenuated in the lesioned striatum. The formation of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the major DA metabolites, was also reduced in the lesioned striata following L-dopa administration; however, the reduction was not as great as was that of DA formation. A significant metabolism of exogenous L-dopa to 3-O-methyldopa occurred in both striata. L-dopa administration transiently increased extracellular levels of 5-hydroxyindoleacetic acid (5 HIAA) in both the lesioned and intract striata. These results suggest that the striatum with a reduction in DA nerve terminals is deficient both in the capacity to synthesize DA and in the storage mechanisms necessary to protect the newly synthesized DA from oxidative metabolism.

Original languageEnglish (US)
Pages (from-to)15-22
Number of pages8
JournalJournal of Neural Transmission - Parkinson's Disease and Dementia Section
Volume2
Issue number1
DOIs
StatePublished - Mar 1 1990

Keywords

  • L-dopa
  • Parkinson's disease
  • cerebral dialysis
  • dopamine

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology

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