UNCHANGED BASAL GANGLIA N-ACETYLASPARTATE AND GLUTAMATE IN IDIOPATHICPARKINSONS-DISEASE MEASURED BY PROTON MAGNETIC-RESONANCE SPECTROSCOPY

The lentiform nucleus of five patients with idiopathic Parkinson's dis ease (IPD) was studied by quantitative magnetic resonance spectroscopy (MRS), both before and after administration of apomorphine, and the s pectra were compared with those from a group of age-matched normal sub jects. The concentrations of the three major metabolites, choline, cre atine, and N-acetylaspartate (NAA), were quantified using tissue water content as an internal concentration reference. Glutamate concentrati on was assessed as the (glutamate + glutamine; GLX)/creatine peak area ratio. In normal subjects, the mean +/- SD concentrations of the thre e metabolites were 2.4 +/- 0.4 mu mol/g wet wt for choline, 11.5 +/- 0 .8 mu mol/g for creatine, and 14.7 +/- 2.8 mu mol/g for NAA. The Glx/c reatine ratio was 1.26 +/- 0.12. There was no significant difference i n these parameters in the lentiform nucleus of patients with IPD eithe r before or after apomorphine. The absence of detectable differences i n IPD in this study implies that the changes in glutamate metabolism i n the basal ganglia predicted by animal work are more subtle than thos e currently observable by MRS.