DECREASED CEREBROSPINAL-FLUID LEVELS OF NEUTRAL AND BASIC-AMINO-ACIDSIN PATIENTS WITH PARKINSONS-DISEASE

We measured the CSF levels of 21, and the plasma levels of 26, amino a cids in 31 patients with Parkinson's disease (PD) and in 45 matched co ntrols. We used an ion-exchange chromatography method. When compared t o controls, PD patients had lower CSF levels of taurine, alanine, vali ne, leucine, isoleucine, ethanolamine, citrulline, ornithine, lysine, histidine, arginine, and alpha-aminobutyric acid. PD patients not trea ted with levodopa or with dopamine agonists had higher CSF tyrosine an d phenylalanine levels than those not treated with these drugs and als o than controls. PD patients had higher plasma levels of phosphoserine , threonine, methionine, tyrosine, sarcosine and alpha-aminoadipic aci d, and lower plasma levels of valine, leucine, and tryptophan, than co ntrols. The CSF/plasma ratio of many of these amino acids was signific antly lower in PD patients than those of controls, suggesting that PD patients might have a dysfunction in the transport of neutral and basi c amino acids across the blood-brain barrier. (C) 1997 Elsevier Scienc e B.V.