Publication Type Academic Article
Authors Dubin M, Mao X, Banerjee S, Goodman Z, Lapidus K, Kang G, Liston C, Shungu D
Journal J Psychiatry Neurosci
Volume 41
Issue 3
Pagination E37-45
Date Published 04/01/2016
ISSN 1488-2434
Keywords Depressive Disorder, Major, Prefrontal Cortex, Transcranial Magnetic Stimulation, gamma-Aminobutyric Acid
Abstract BACKGROUND: GABAergic and glutamatergic neurotransmitter systems are central to the pathophysiology of depression and are potential targets of repetitive transcranial magnetic stimulation (rTMS). We assessed the effect of 10-Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) of patients with major depressive disorder on the levels of medial prefrontal cortex (MPFC) γ-aminobutyric acid (GABA) and the combined resonance of glutamate and glutamine (Glx) as assessed in vivo with proton magnetic resonance spectroscopy ((1)H MRS). METHODS: Currently depressed individuals between the ages of 23 and 68 years participated in a 5-week naturalistic, open-label treatment study of rTMS, with (1)H MRS measurements of MPFC GABA and Glx levels at baseline and following 5 weeks of the rTMS intervention. We applied rTMS pulses over the left DLPFC at 10 Hz and 80%-120% of motor threshold for 25 daily sessions, with each session consisting of 3000 pulses. We assessed therapeutic response using the 24-item Hamilton Rating Scale for Depression (HAMD24). The GABA and Glx levels are expressed as ratios of peak areas relative to the area of the synchronously acquired and similarly fitted unsuppressed voxel water signal (W). RESULTS: Twenty-three currently depressed individuals (7 men) participated in the study. GABA/W in the MPFC increased 13.8% (p = 0.013) in all depressed individuals. There were no significant effects of rTMS on Glx/W. GABA/W and Glx/W were highly correlated in severely depressed patients at baseline but not after TMS. LIMITATIONS: The primary study limitations are the open-label design and the inclusion of participants currently taking stable regimens of antidepressant medications. CONCLUSION: These results implicate GABAergic and glutamatergic systems in the mechanism of action of rTMS for major depression, warranting further investigation in larger samples.
DOI 10.1503/jpn.150223
PubMed ID 26900793
PubMed Central ID PMC4853214
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