PRESYNAPTIC DOPAMINERGIC FUNCTION IN THE STRIATUM OF SCHIZOPHRENIC-PATIENTS

The dopaminergic hypothesis of schizophrenia postulates increased brai n dopaminergic activity. Two previous studies reported increased F-18- DOPA uptake with positron emission tomography in schizophrenic patient s (n=5, n=7). In the present study, striatal dopaminergic function was assessed in vivo in six untreated schizophrenics and seven control su bjects, comparable for age and sex. The F-18-fluoro-L-DOPA (F-18-DOPA) uptake rate constant K-i was determined in the caudate and putamen us ing coregistered positron emission tomography and magnetic resonance i maging. No difference between groups for mean K-i was found. The varia bility of the F-18-DOPA uptake values was higher in the caudate (p<0.0 1) and in the putamen (p<0.001) in schizophrenic patients than in cont rol subjects, suggesting that schizophrenia is a disorder involving he terogeneous states of the striatal presynaptic dopaminergic function.