Up-regulation of the D1 dopamine receptor-interacting protein, calcyon, in patients with schizophrenia.
BACKGROUND
The dopamine hypothesis remains a prominent influence on research into the pathogenesis of schizophrenia, yet the presence of consistent schizophrenia-linked abnormalities in the presynaptic components of the dopamine system or in dopamine receptors still remains a matter of debate. The present study focuses on a recently recognized group of dopamine receptor-interacting proteins as possible novel sites of dysfunction in schizophrenia. Specifically, we examined whether the D1 dopamine receptor-interacting protein calcyon and the D2 dopamine receptor-interacting proteins filamin-A and spinophilin are affected in the dorsolateral prefrontal cortex of patients with schizophrenia.


METHODS
Slot blots of dorsolateral prefrontal cortical tissue were used to compare the levels of the 3 proteins of interest in control, schizophrenic, bipolar, and major depression groups (n = 15 per group). The nonschizophrenic psychiatric groups were included to determine the specificity of the detected abnormalities.


RESULTS
The dorsolateral prefrontal cortex in schizophrenic patients displayed nearly twice the normal levels of calcyon, whereas filamin-A and spinophilin levels were unaltered. Patients with bipolar disorder or major depression showed no changes in all 3 proteins examined.


CONCLUSIONS
Our findings provide the first evidence that abnormalities in the dopamine system of patients with schizophrenia may lie in altered levels of dopamine receptor-interacting proteins.
Koh
Phil Ok
PO
Department of Oral and Craniofacial Biological Sciences, University of Maryland, Baltimore 21201, USA.
Bergson
Clare
C
Undie
Ashiwel S
AS
Goldman-Rakic
Patricia S
PS
Lidow
Michael S
MS
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001714:Bipolar Disorder / Q000175:diagnosis / Q000378:metabolism; D015153:Blotting, Western; D002452:Cell Count; D003285:Contractile Proteins / Q000032:analysis / Q000378:metabolism; D003866:Depressive Disorder / Q000175:diagnosis / Q000378:metabolism; D005260:Female; D064448:Filamins; D007839:Functional Laterality; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D008840:Microfilament Proteins / Q000032:analysis / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000378:metabolism; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D017397:Prefrontal Cortex / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D017447:Receptors, Dopamine D1 / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D012559:Schizophrenia / Q000175:diagnosis / Q000378:metabolism*; D015854:Up-Regulation; D000099273:Neurabins
D014150:Antipsychotic Agents; D003285:Contractile Proteins; D064448:Filamins; D006220:Haloperidol; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D017447:Receptors, Dopamine D1; D000099273:Neurabins; C405464:calcyon