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Dose relationship of limbic-cortical D2-dopamine receptor occupancy with risperidone
1National Institute of Radiological Sciences, Chiba-shi, Japan. suhara@nirs.go.jp
Psychopharmacology
|April 9, 2001
Summary
This study measured limbic-cortical dopamine D2 receptor occupancy in schizophrenia patients treated with risperidone. Results show occupancy similar to the striatum, suggesting comparable efficacy to typical antipsychotics.
Area of Science:
- Neuroscience
- Psychopharmacology
- Radiochemistry
Background:
- Antipsychotic efficacy is linked to dopamine D2 receptor antagonism in limbic-cortical regions.
- Risperidone exhibits atypical properties, but its limbic-cortical D2 receptor effects remain uncharacterized.
Purpose of the Study:
- To investigate the relationship between risperidone dosage and limbic-cortical dopamine D2 receptor occupancy.
- To utilize positron emission tomography (PET) for quantitative receptor occupancy assessment.
Main Methods:
- Seven schizophrenia patients underwent PET scans with [11C]FLB 457 during steady-state risperidone treatment.
- Dopamine D2 receptor occupancy was quantified in limbic-cortical brain regions.
Main Results:
- Observed average D2 receptor occupancy ranged from 38% to 80% with daily risperidone doses of 1-6 mg.
- A saturation curve model effectively described the relationship between drug levels and receptor occupancy.
Conclusions:
- Risperidone achieves significant D2 receptor occupancy in limbic-cortical regions.
- This occupancy is comparable to that observed in the striatum and with typical antipsychotics, supporting its therapeutic potential.