title: Transcranial magnetic stimulation potentiates glutamatergic neurotransmission in depressed adolescents.
abstract: Abnormalities in glutamate neurotransmission may have a role in the pathophysiology of adolescent depression. The present pilot study examined changes in cortical glutamine/glutamate ratios in depressed adolescents receiving high-frequency repetitive transcranial magnetic stimulation. Ten adolescents with treatment-refractory major depressive disorder received up to 30 sessions of 10-Hz repetitive transcranial magnetic stimulation at 120% motor threshold with 3000 pulses per session applied to the left dorsolateral prefrontal cortex. Baseline, posttreatment, and 6-month follow-up proton magnetic resonance spectroscopy scans of the anterior cingulate cortex and left dorsolateral prefrontal cortex were collected at 3T with 8-cm(3) voxels. Glutamate metabolites were quantified with 2 distinct proton magnetic resonance spectroscopy sequences in each brain region. After repetitive transcranial magnetic stimulation and at 6 months of follow-up, glutamine/glutamate ratios increased in the anterior cingulate cortex and left dorsolateral prefrontal cortex with both measurements. The increase in the glutamine/glutamate ratio reached statistical significance with the TE-optimized PRESS sequence in the anterior cingulate cortex. Glutamine/glutamate ratios increased in conjunction with depressive symptom improvement. This reached statistical significance with the TE-optimized PRESS sequence in the left dorsolateral prefrontal cortex. High-frequency repetitive transcranial magnetic stimulation applied to the left dorsolateral prefrontal cortex may modulate glutamate neurochemistry in depressed adolescents.
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States. Electronic address: croarkin.paul@mayo.edu.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Croarkin
authors.affiliation: Department of Clinical Sciences, Division of Biostatistics, UT Southwestern Medical Center, Dallas, Texas, United States.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Nakonezny
authors.affiliation: PrairieCare, Rochester, Minnesota, United States.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Wall
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Lauren L
authors.initials: LL
authors.lastname: Murphy
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Shirlene M
authors.initials: SM
authors.lastname: Sampson
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Frye
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, United States; Department of Radiology, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: John D
authors.initials: JD
authors.lastname: Port
mesh_terms: D000293:Adolescent; D001921:Brain / Q000503:physiopathology; D003865:Major Depressive Disorder / Q000378:metabolism / Q000523:psychology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D018698:Glutamic Acid / Q000378:metabolism*; D006179:Gyrus Cinguli / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008297:Male; D010865:Pilot Projects; D017397:Prefrontal Cortex / Q000378:metabolism* / Q000503:physiopathology; D011446:Prospective Studies; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D009435:Synaptic Transmission; D050781:Transcranial Magnetic Stimulation / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D018698:Glutamic Acid
keywords: Adolescent depression; Glutamate; Glutamine; Proton magnetic resonance spectroscopy; Repetitive transcranial magnetic stimulation