Higher striatal dopamine transporter density in PTSD: an in vivo SPECT study with [(99m)Tc]TRODAT-1.
BACKGROUND
Some evidence suggests a hyperdopaminergic state in posttraumatic stress disorder (PTSD). The 9-repetition allele (9R) located in the 3' untranslated region of the dopamine transporter (DAT) gene (SLC6A3) is more frequent among PTSD patients. In vivo molecular imaging studies have shown that healthy 9R carriers have increased striatal DAT binding. However, no prior study evaluated in vivo striatal DAT density in PTSD.


OBJECTIVE
The objective of this study was to evaluate in vivo striatal DAT density in PTSD.


METHODS
Twenty-one PTSD subjects and 21 control subjects, who were traumatized but asymptomatic, closely matched comparison subjects evaluated with the Clinician-Administered PTSD Scale underwent a single-photon emission computed tomography scan with [(99m)TC]-TRODAT-1. DAT binding potential (DAT-BP) was calculated using the striatum as the region of the interest and the occipital cortex as a reference region.


RESULTS
PTSD patients had greater bilateral striatal DAT-BP (mean ± SD; left, 1.80 ± 0.42; right, 1.78 ± 0.40) than traumatized control subjects (left, 1.62 ± 0.32; right, 1.61 ± 0.31; p = 0.039 for the left striatum and p = 0.032 for the right striatum).


CONCLUSIONS
These results provide the first in vivo evidence for increased DAT density in PTSD. Increases in DAT density may reflect higher dopamine turnover in PTSD, which could contribute to the perpetuation and potentiation of exaggerated fear responses to a given event associated with the traumatic experience. Situations that resemble the traumatic event turn to be interpreted as highly salient (driving attention, arousal, and motivation) in detriment of other daily situations.
Instituto do Cérebro, Instituto de Ensino e Pesquisa do Hospital Israelita Albert Einstein, São Paulo, Brazil. mqhoexter@gmail.com
Marcelo Q
MQ
Hoexter
Gustavo
G
Fadel
André C
AC
Felício
Mariana B
MB
Calzavara
Ilza R
IR
Batista
Marilia A
MA
Reis
Ming C
MC
Shih
Roger K
RK
Pitman
Sérgio B
SB
Andreoli
Marcelo F
MF
Mello
Jair J
JJ
Mari
Rodrigo A
RA
Bressan
D000293:Adolescent; D000328:Adult; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes; D055815:Young Adult
D050483:Dopamine Plasma Membrane Transport Proteins; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; D004298:Dopamine