Changes in putamen N-acetylaspartate and choline ratios in untreated and levodopa-treated Parkinson's disease: a proton magnetic resonance spectroscopy study.
We have carried out single-voxel proton magnetic resonance spectroscopy centered on the putamen both ipsilateral and contralateral to the worst affected side in nine subjects with drug naive idiopathic Parkinson's disease (IPD); seven chronically levodopa-treated dyskinetic IPD subjects; and 11 age-matched healthy controls. Measurements of N-acetylaspartate (NAA)/choline (Cho), NAA/(Creatine + Phosphocreatine) (Cr + PCr), and Cho/(Cr + PCr) were made. We found a significant reduction in NAA/Cho ratios from the putamen contralateral to the most affected side in the drugnaive group (p = 0.009), but not the levodopa-treated IPD groups compared with controls. There were no significant differences in NAA/(Cr + PCr) or Cho/(Cr + PCr) ratios. In untreated IPD, reduced putaminal NAA/Cho ratios may reflect loss of nigrostriatal dopamine terminals or alternatively indicate a functional abnormality of striatal putaminal neurons, such as membrane dysfunction due to striatal deafferentation. This study suggests that NAA/Cho ratios may be affected by L-dopa therapy and this may provide a reversible marker of neuronal dysfunction in the striatum.
Ellis
C M
CM
Movement Disorders and Neurodegeneration Unit, King's College Hospital, London, UK.
Lemmens
G
G
Williams
S C
SC
Simmons
A
A
Dawson
J
J
Leigh
P N
PN
Chaudhuri
K R
KR
D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002794:Choline / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism; D015259:Dopamine Agents / Q000627:therapeutic use*; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D011522:Protons; D011699:Putamen / Q000378:metabolism*; D012016:Reference Values
D000978:Antiparkinson Agents; D015259:Dopamine Agents; D011522:Protons; D010725:Phosphocreatine; D001224:Aspartic Acid; D007980:Levodopa; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline