title: Antidepressant-like effects of cranial stimulation within a low-energy magnetic field in rats.
abstract: BACKGROUND
  Evidence suggests that a novel type of magnetic resonance imaging (MRI) scan called echo planar magnetic resonance spectroscopic imaging (EP-MRSI) has mood-elevating actions in humans during the depressive phases of bipolar disorder. We examined whether a low-energy component of EP-MRSI (low-field magnetic stimulation [LFMS]) has antidepressant-like, locomotor-stimulating, or amnestic effects in rats.
  
  
  METHODS
  We examined the effects of LFMS on immobility in the forced swim test (FST) and activity within an open field in separate groups of rats. After exposure to forced swimming, rats received LFMS (three 20-min sessions at 1.5 G/cm and .75 V/m) before behavioral testing. We also examined the effects of LFMS on fear conditioning (FC), a learning paradigm that also involves exposure to stressful conditions.
  
  
  RESULTS
  Low-field magnetic stimulation reduced immobility in the FST, an antidepressant-like effect qualitatively similar to that of standard antidepressants. Low-field magnetic stimulation did not alter locomotor activity or FC.
  
  
  CONCLUSIONS
  Low-field magnetic stimulation has antidepressant-like effects in rats that seem unrelated to locomotor-activating or amnestic effects. These findings raise the possibility that electromagnetic fields can affect the brain biology and might have physiologic consequences that offer novel approaches to therapy for psychiatric disorders. These same consequences might render MRI-based scans more invasive than previously appreciated.
authors.affiliation: Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, MA 02478, USA. carlezon@mclean.harvard.edu
authors.forename: William A
authors.initials: WA
authors.lastname: Carlezon
authors.forename: Michael L
authors.initials: ML
authors.lastname: Rohan
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Mague
authors.forename: Edward G
authors.initials: EG
authors.lastname: Meloni
authors.forename: Aram
authors.initials: A
authors.lastname: Parsegian
authors.forename: Kenroy
authors.initials: K
authors.lastname: Cayetano
authors.forename: Hilarie C
authors.initials: HC
authors.lastname: Tomasiewicz
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Rouse
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Cohen
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
mesh_terms: D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use; D000929:Antidepressive Agents, Tricyclic / Q000627:therapeutic use; D001522:Behavior, Animal / Q000187:drug effects / Q000528:radiation effects; D001921:Brain / Q000187:drug effects / Q000503:physiopathology / Q000528:radiation effects*; D003213:Conditioning, Psychological / Q000528:radiation effects; D003863:Depression / Q000628:therapy*; D003891:Desipramine / Q000627:therapeutic use; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D017352:Echo-Planar Imaging / Q000379:methods*; D004574:Electromagnetic Fields; D005239:Fear; D005473:Fluoxetine / Q000627:therapeutic use; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D009043:Motor Activity / Q000528:radiation effects; D010812:Physical Stimulation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000528:radiation effects; D013550:Swimming; D013997:Time Factors
chemical_list: D018687:Antidepressive Agents, Second-Generation; D000929:Antidepressive Agents, Tricyclic; D005473:Fluoxetine; D003891:Desipramine