Excitatory amino acids, monoamines, neuropeptide Y and cholecystokinin in cerebrospinal fluid of Parkinson patients

The levels of excitatory amino acids (EAA), monoamines, neuropeptide Y (NPY) and cholecystokinin were quantitated in cerebrospinal fluid (CSF) in the patients with Parkinson's disease (PD). The results accumulated showed that the levels of aspartate (ASP), glutamate (GLU) and noradrenaline (NA) in the CSF were higher while that of dopamine (DA) and cholecystokinin octapeptide (CCK-8) were lower in untreated PD patients. There were no change in NPY and 5-hydroxy tryptamine (5-HT) levels in L-DOPA treated or untreated PD patients. With the exception of the low level of CCK-8 and the unchanged NPY, these alterations in ASP, GLU and DA levels were partially or completely reversed after treatment with L-DOPA. These results suggest that GLU secretion is enhanced in PD and that DAergic treatment normalizes not only DA, but also ASP and GLU levels. These findings support the hypothesis that GLU and DA interact in the human brain. The unchanged levels of NPY and 5-HT reflect non-depression state in PD patients.