title: Levodopa and 3-O-methyldopa in cerebrospinal fluid after levodopa-carbidopa association.
abstract: Since motor fluctuations in Parkinsonian patients might be, at least in part, explained by an antagonism between levodopa (LD) and its metabolite 3-O-methyldopa (3-OMD) at blood-brain-barrier (BBB), we decided to study LD and 3-OMD plasma and cerebrospinal fluid (CSF) levels in subjects undergoing lumbar puncture for diagnostic purposes. After informed consent, 70 subjects took a tablet of carbidopa-levodopa association (Sinemet or Sinemet-CR) 0.5, 1, 2, 4, 8, 12 h before blood and lumbar cerebrospinal fluid collection. LD and 3-OMD were determined by an HPLC-electrochemical method. The subjects treated with Sinemet-CR had lower LD cerebrospinal fluid concentrations along with lower LD and higher 3-OMD plasma concentrations. This pattern of LD cerebrospinal fluid concentrations may be explained by means of a transport competition between LD and 3-OMD at blood brain barrier level.
authors.affiliation: Institute of Neurology, University of Padua, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Benetello
authors.forename: M
authors.initials: M
authors.lastname: Furlanut
authors.forename: M
authors.initials: M
authors.lastname: Fortunato
authors.forename: F
authors.initials: F
authors.lastname: Pea
authors.forename: M
authors.initials: M
authors.lastname: Baraldo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000134:cerebrospinal fluid* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D004338:Drug Combinations; D004563:Electrochemistry; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000134:cerebrospinal fluid* / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D014443:Tyrosine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics
chemical_list: D000978:Antiparkinson Agents; D004338:Drug Combinations; D014443:Tyrosine; D007980:Levodopa; C008404:3-methoxytyrosine