A single photon emission computed tomography scan study of striatal dopamine D2 receptor binding with 123I-epidepride in patients with schizophrenia and controls.
The usefulness of 123I-epidepride as a single photon emission computed tomography (SPECT) scan D2 receptor ligand was examined in vivo in 13 medicated patients with schizophrenia and age- and sex-matched normal controls. To establish the effect of endogenous dopamine on 123I-epidepride binding, 4 of the 13 controls also received 20 mg D-amphetamine. The results showed that 123I-epidepride had high specific binding to the striatum in both patients with schizophrenia and normal controls. There was a trend for the total striatal binding of medicated patients with schizophrenia, as measured by total basal ganglia: frontal cortex (TBG:FC) ratios, to be less than the binding of controls (P = 0.053). This trend confirms previous work showing that antipsychotic medication decreases the number of D2 receptors available for binding to the radioligand. Interestingly, there was also a significant relationship between 123I-epidepride binding ratios and global functioning scales (Global Assessment of Functioning scale [GAF]) for schizophrenia (r = 0.56, P = 0.045), although there was no such relationship with the Brief Psychiatric Rating Scale (BPRS). In addition, our results showed that amphetamine-induced dopamine release did not alter 123I-epidepride binding, confirming the high specific binding of 123I-epidepride to the D2 receptor. We conclude that 123I-epidepride appears to be a very useful SPECT ligand for imaging the D2 receptor.
Tibbo
P
P
Department of Psychiatry, University of Alberta, Edmonton, Canada.
Silverstone
P H
PH
McEwan
A J
AJ
Scott
J
J
Joshua
A
A
Golberg
K
K
D000328:Adult; D000661:Amphetamine / Q000008:administration & dosage / Q000494:pharmacology; D001479:Basal Ganglia / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D001549:Benzamides / Q000378:metabolism / Q000493:pharmacokinetics*; D001665:Binding Sites / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011759:Pyrrolidines / Q000378:metabolism / Q000493:pharmacokinetics*; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon
D001549:Benzamides; D000697:Central Nervous System Stimulants; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C063525:epidepride; D000661:Amphetamine