GABA system in schizophrenia and mood disorders. A mini review on third generation imaging studies

Frontiers in Psychiatry

Gianfranco eSpalletta¹  Federica ePiras²  Fabrizio ePiras³  Carlo eCaltagirone⁴  Chiara eChiapponi⁴ 

[1] Baylor College of Medicine;Fondazione Santa Lucia;Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi;University of Rome Tor Vergata;

关键词: Bipolar Disorder;    Schizophrenia;    GABA;    Major Depressive Disorder;    Multimodal Imaging;    MRS;   

DOI  :  10.3389/fpsyt.2016.00061

来源: DOAJ

【 摘 要 】

Third-generation neuroimaging research has been enriched by advances in magnetic resonance spectroscopy (MRS) measuring the concentration of important neurotrasmitters, such as the inhibitory amino acid GABA. Here, we performed a systematic mini-review on brain MRS studies measuring GABA concentration in patients affected by schizophrenia (SZ), bipolar disorder (BD) and major depressive disorder (MDD). We wondered whether multimodal investigations could overcome intrinsic technical limits of MRS giving a broader view of mental disorders pathogenesis.In SZ unimodal studies gave mixed results, as increased, decreased or unaltered GABA levels were reported depending on region, disease phase and treatment. Conversely, multimodal results showed reduced level of glutamate, but not of GABA, in patients, mirrored by in vitro biochemical findings revealing hippocampal reduction in glutamate signalling in SZ, and no deficits in GABA synthesis. Moreover, a mouse model confirmed the unique pathological characteristic of glutamate function in SZ.Unimodal studies in BD revealed, again, inconsistent results, while no multimodal investigations including MRS on GABA exist. In MDD, unimodal studies could not differentiate patients from controls, nor characterize high-risk subjects and remitted patients. However, a multimodal study combining functional magnetic resonance imaging and MRS revealed that cingulate cortex activity is related to glutamate and N-acetylaspartate levels and anhedonia in patients, and to GABA concentration in healthy subjects, improving the distinction between MDD and physiology.Overall, our results show that unimodal studies do not indicate GABA as a biomarker for the psychiatric disorders considered. Conversely, multimodal studies can widen the understanding of the link between psychopathology, genetics, neuroanatomy and functional-biochemical brain activity in mental disorders. Although scarce, multimodal approaches seem promising for moving from GABA MRS unimodal-descriptive to causal level, and for integrating GABA results into a more comprehensive interpretation of mental disorder pathophysiology.

【 授权许可】

Unknown