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Published on: September 8, 2021
Schizophrenia and dopamine receptors
1Department of Psychiatry, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6; Department of Pharmacology, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6.
Summary
Schizophrenia patients exhibit heightened sensitivity to dopamine drugs, potentially due to increased D2High receptors. This finding offers new insights into dopamine receptor function in psychosis.
Area of Science:
- Neuroscience
- Psychiatry
- Pharmacology
Background:
- Schizophrenia patients display behavioral supersensitivity to dopamine-like drugs, experiencing increased psychotic symptoms.
- This supersensitivity may be linked to elevated dopamine release or increased D2/D2High receptors in schizophrenia.
Purpose of the Study:
- To investigate the role of D2High receptors in the behavioral dopamine supersensitivity observed in schizophrenia.
- To explore the in vivo and in vitro evidence for elevated D2High receptor states in schizophrenia.
Main Methods:
- Review of brain imaging studies on D2 receptor levels in antipsychotic-free schizophrenia patients.
- Analysis of in vitro and in vivo studies examining D2High receptor states in animal models and human patients.
- Comparison of D2High receptor elevations in schizophrenia with those in animal models of psychosis.
Main Results:
- While pre-synaptic dopamine release is normal in stable schizophrenia, D2 receptors are elevated by 5.8% in antipsychotic-free patients.
- Two studies showed an 80% increase in apparent D2High receptors in schizophrenia patients after dopamine reduction.
- Elevated D2High receptors in vivo in schizophrenia align with in vitro findings in animal models of psychosis.
Conclusions:
- The elevation of apparent D2High receptors in vivo in schizophrenia patients is consistent with behavioral dopamine supersensitivity.
- Increased D2High receptor states may underlie the heightened drug response observed in schizophrenia.
- Further research into D2High receptor function could inform novel therapeutic strategies for schizophrenia.
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