Nicholas D Mitchell

University of Alberta, Edmonton, Alberta, Canada

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Publications (3)13.54 Total impact

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    ABSTRACT: The medial prefrontal cortex (MPFC) is a key brain area in depressive symptomatology; specifically, glutamate (Glu) has been reported to play a significant role in major depression (MD) in this area. MPFC Glu levels are sensitive to ovarian hormone fluctuations and pregnancy and the postpartum period are associated with the most substantial physiological alterations of female hormones. It is therefore logical to measure MPFC Glu levels in women with postpartum depression (PPD). Using in vivo magnetic resonance spectroscopy (MRS) at a field strength of 3 T, we acquired single-voxel spectra from the MPFC of 12 women with PPD and 12 healthy controls (HCs) matched for postpartum scan timing. Water-referenced MPFC Glu levels were measured using a MRS technique that allowed us to be specific for Glu with very little glutamine contamination. The concentrations of other water-quantified brain metabolites such as glycerophosphorylcholine plus phosphorylcholine, N-acetylaspartate (NAA), and creatine plus phosphocreatine were measured in the same MR spectra. MPFC Glu levels were higher in women with PPD (7.21±1.20) compared to matched HCs (6.04±1.21). There were no differences between groups for other brain metabolites measured. These findings suggest an association between Glu dysregulation in the MPFC and PPD. Whether the pathophysiology of PPD differs from the pathophysiology of MD remains to be determined. Further investigations are needed to determine the chronological associations between the occurrence of symptoms of PPD and the onset of changes in MPFC Glu levels.
    Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 07/2012; 37(11):2428-35. · 8.68 Impact Factor
  • Nicholas D Mitchell, G B Baker
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    ABSTRACT: To review the literature on the involvement of glutamate (Glu), including its interactions with other neurochemical systems, in the pathophysiology of depression. A MEDLINE search using the terms glutamate, depression and major depressive disorder, was performed. Alterations in proteins involved in glutamatergic signalling are implicated in variations in behaviour in animal models of depression. Drugs acting at Glu receptors appear to have antidepressant-like effects in these models, and traditional antidepressant pharmacotherapies act on the glutamatergic system. Recent evidence from genetic studies and in vivo spectroscopy also correlate glutamatergic dysfunction with depression. Trials of N-methyl-d-aspartate receptor antagonists in humans have provided mixed results. A growing body of evidence indicates that the glutamatergic system is involved in the pathophysiology of depression, and may represent a target for intervention.
    Acta Psychiatrica Scandinavica 09/2010; 122(3):192-210. · 4.86 Impact Factor
  • Glen B. Baker, Nicholas D. Mitchell
    05/2008; , ISBN: 9780470048672