Subscribe to RSS
Pharmacological modulation of dopaminergic systems in neuropsychiatric disorders studied with positron emission tomography
We have recently shown that subchronic treatment with haloperidol downregulates dopamine synthesis capacity in patients with schizophrenia as measured with [18F]FDOPA PET (Gründer et al., Neuropsychopharmacology 2003). In order to further study the regulation of dopamine synthesis by pharmacological treatment, we administered haloperidol acutely to eight normal volunteers (5mg/day for 3 days) and performed [18F]FDOPA PET scans pre and post haloperidol. Preliminary analysis of data obtained in five subjects revealed no consistent change in Ki or k3 after acute haloperidol. On the other hand, acute levodopa seems to increase FDOPA influx in normal striatum, whereas it decreases this parameter in patients with Parkinson’s disease (Cumming et al., submitted). Moreover, data obtained in drug-free patients with schizophrenia and detoxified alcoholics show region-specific changes in FDOPA influx, which will be presented in more detail at the meeting. This presentation will review the factors that may influence the susceptibility of the method to detect changes in dopamine synthesis capacity in disease states and after drug challenges.