title: The significance of 3-O-methyldopa concentrations in the cerebrospinal fluid in the pathogenesis of wearing-off phenomenon in Parkinson's disease.
abstract: We determined concentrations of 3-O-methyldopa (3-OMD), L-3,4-dihydroxyphenylalanine (L-dopa), dopamine (DA) and other related substances in the cerebrospinal fluid in patients with Parkinson's disease (PD) 15 h after L-dopa/carbidopa medication, and compared patients with and without the wearing-off phenomenon. Concentrations of 3-OMD significantly increased, and the ratio of DA to 3-OMD was significantly shifted in favor of 3-OMD in patients with the wearing-off compared with patients without the wearing-off. However, concentrations of L-dopa, DA, and homovanillic acid (HVA) were not different between the groups. These results suggest that even if 3-OMD is related to the pathogenesis of the wearing-off, it is not through competition with L-dopa for uptake into the brain, but through other unknown mechanisms within the brain.
authors.affiliation: Department of Neurology, Iwate Medical University, Morioka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tohgi
authors.forename: T
authors.initials: T
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Kikuchi
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Nozaki
mesh_terms: D015306:Biogenic Monoamines / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid; D002230:Carbidopa / Q000627:therapeutic use*; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008875:Middle Aged; D010300:Parkinson Disease / Q000134:cerebrospinal fluid* / Q000188:drug therapy / Q000503:physiopathology; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000134:cerebrospinal fluid
chemical_list: D015306:Biogenic Monoamines; D015415:Biomarkers; D014443:Tyrosine; D007980:Levodopa; D002230:Carbidopa; C008404:3-methoxytyrosine