Dual-isotope SPECT imaging of striatal dopamine: first episode, drug naïve schizophrenic patients.
OBJECTIVE
The aim of this investigation was to evaluate the usefulness of a dual-isotope SPECT technique to assess simultaneously striatal dopamine binding structures - presynaptic dopamine transporter (DAT) and postsynaptic dopamine D(2) receptor - in first-episode, drug-naive schizophrenic patients compared to healthy control persons. Additionally, relations between radioligand binding to DAT and D(2) and positive symptoms were assessed.


METHODS
Twenty acutely ill inpatients suffering from a first acute schizophrenic episode and 12 healthy control persons participated in the study. Patients were naïve with respect to neuroleptic or antidepressant medication. A dual-isotope SPECT protocol was performed using combined application of [99mTc]TRODAT-1 and [123I]IBZM. On the day of SPECT, psychopathology was assessed in the patient group by PANSS rating.


RESULTS
In the patient but not in the healthy control group there was a significant correlation between DAT and D(2) receptor availability. Patients with predominant positive symptoms (n=12) had a significantly higher DAT availability compared to the healthy control group. An inverse correlation between DAT and D(2) availability and the extent of "delusions", "conceptual disorganization", and "hallucinatory behaviour" could be demonstrated.


CONCLUSIONS
The data obtained with this dual-isotope SPECT technique show a change in interaction between striatal DAT and D(2) receptor in first-episode, never-treated schizophrenic patients. Additionally, an association between dopamine transmission and the core symptoms of the acute psychotic syndrome was found.
Schmitt
G J E
GJ
Department of Psychiatry, Ludwig-Maximilians-University Munich, Nussbaumstr. 7, 80336 München, Germany. gisela.schmitt@med.uni-muenchen.de
la Fougère
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C
Dresel
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Frodl
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Hahn
K
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Möller
H-J
HJ
Meisenzahl
E M
EM
D000328:Adult; D000704:Analysis of Variance; D001549:Benzamides; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D015609:Organotechnetium Compounds; D011569:Psychiatric Status Rating Scales; D011759:Pyrrolidines; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
D001549:Benzamides; D015609:Organotechnetium Compounds; D011759:Pyrrolidines; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide; D004298:Dopamine