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5-HT2A receptor blockade in patients with schizophrenia treated with risperidone or clozapine. A SPET study using the novel 5-HT2A ligand 123I-5-I-R-91150.
- Source :
-
The British journal of psychiatry : the journal of mental science [Br J Psychiatry] 1998 Sep; Vol. 173, pp. 236-41. - Publication Year :
- 1998
-
Abstract
- Background: 5-HT2A receptor antagonism may be crucial to the action of atypical antipsychotics. Previous work has related 5-HT2A receptor blockade to clinical efficacy and protection from extrapyramidal side-effects.<br />Method: We developed a SPET imaging protocol for assessing 5-HT2A receptor binding using the selective ligand 123I-5-I-R91150. Six healthy volunteers, five clozapine- and five risperidone-treated subjects with DSM-IV schizophrenia were studied. Multi-slice SPET was performed on each subject.<br />Results: Cortex:cerebellum ratios were significantly lower in both clozapine- and risperidone-treated subjects compared with the healthy volunteers in all cortical regions. There was no difference in occupancy between the two drug-treated groups. No correlation was found between the percentage change in the Global Assessment Scale (GAS) and 5-HT2A receptor binding indices in the drug-treated groups.<br />Conclusions: Clozapine and risperidone potently block 5-HT2A receptors in vivo. The lack of relationship between receptor binding indices and change in GAS suggests that 5-HT2A receptor blockade may be unrelated to clinical improvement. Future studies will substantiate this finding by studying 5-HT2A receptor binding in large groups of patients treated with both typical and novel atypical antipsychotics.
- Subjects :
- Adult
Basal Ganglia Diseases chemically induced
Basal Ganglia Diseases metabolism
Clozapine metabolism
Female
Humans
Iodine Radioisotopes
Male
Piperidines
Risperidone metabolism
Schizophrenia diagnostic imaging
Schizophrenia metabolism
Serotonin Antagonists metabolism
Tomography, Emission-Computed, Single-Photon
Clozapine therapeutic use
Receptors, Serotonin metabolism
Risperidone therapeutic use
Schizophrenia drug therapy
Serotonin Antagonists therapeutic use
Subjects
Details
- Language :
- English
- ISSN :
- 0007-1250
- Volume :
- 173
- Database :
- MEDLINE
- Journal :
- The British journal of psychiatry : the journal of mental science
- Publication Type :
- Academic Journal
- Accession number :
- 9926100
- Full Text :
- https://doi.org/10.1192/bjp.173.3.236