Effects of repetitive transcranial magnetic stimulation on [11C]raclopride binding and cognitive function in patients with depression.
BACKGROUND
Several studies have demonstrated that repetitive transcranial magnetic stimulation (rTMS) elicits moderate antidepressant effects. Several previous studies suggested that the dopaminergic system might be related to this therapeutic action of rTMS. We attempted to determine the effects of chronic rTMS on central dopaminergic function in depression using positron emission tomography (PET) with [11C]raclopride.


METHODS
Nine patients with depression were treated with 10 daily sessions of rTMS (10 Hz, 5 s train, 20 trains at 100% motor threshold per session) over the left dorsolateral prefrontal cortex (DLPFC). Each patient underwent two [11C]raclopride PET scans and neuropsychological tests - before rTMS and 1 day after rTMS.


RESULTS
In five patients, the Hamilton Rating Scale for Depression (HRSD) significantly decreased. Patients showed significant improvement in verbal memory following rTMS. There were no changes in [11C]raclopride binding in the caudate nucleus and putamen after rTMS treatment.


CONCLUSIONS
Our sample size was limited, and our study was an open trial lacking sham-treated controls.


CONCLUSIONS
This study suggests that rTMS may be effective for the treatment of depression and also may improve verbal memory function. We observed no changes in [11C]raclopride binding, suggesting that there was no measurable increase in the release of dopamine at the second PET scan. Several animal studies and healthy human studies have indicated that dopamine can be released soon after acute rTMS. Our results suggest that release of striatal dopamine induced by rTMS may be only transient, or that dopamine release may be attenuated following chronic rTMS.
Kuroda
Yuko
Y
Section of Psychiatry and Behavioral Science, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan.
Motohashi
Nobutaka
N
Ito
Hiroshi
H
Ito
Shigeo
S
Takano
Akihiro
A
Nishikawa
Toru
T
Suhara
Tetsuya
T
D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use; D003071:Cognition / Q000187:drug effects*; D003865:Major Depressive Disorder / Q000378:metabolism* / Q000523:psychology / Q000628:therapy; D004298:Dopamine / Q000096:biosynthesis; D018492:Dopamine Antagonists / Q000378:metabolism*; D005260:Female; D016666:Fluvoxamine / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D020891:Raclopride / Q000378:metabolism*; D012720:Severity of Illness Index; D050781:Transcranial Magnetic Stimulation
D018687:Antidepressive Agents, Second-Generation; D018492:Dopamine Antagonists; D020891:Raclopride; D016666:Fluvoxamine; D004298:Dopamine