It cannot be ruled out, however, that some of the cellular alterations in mood Brefeldin A disorders are related to prior treatment with antidepressants and lithium (for further discussion see reference 85). The question of whether cell abnormalities can be attributed to the effect of therapeutic medications is open to debate. There have been no
systematic studies on the effect of antidepressant and mood-stabilizing medications on cell Inhibitors,research,lifescience,medical number and morphology in the postmortem human brain, most likely due to an insufficient number of treated versus untreated subjects. Conclusion Cellular abnormalities in mood disorders are observed in the dorsolateral prefrontal cortex, anterior cingulated cortex, orbitofrontal cortex, hippocampus, and amygdala. In these same brain regions, neuroimaging studies reveal volumetric, metabolic, and neurochemical alterations in subjects with mood disorders. Structural neuroimaging
studies in mood disorders Inhibitors,research,lifescience,medical provide evidence of modest but intriguing volumetric changes that suggest cell loss and/or atrophy.86 Some studies, but not all, report, enlargement of the lateral and third ventricles in mood disorders87 that may be indicative of atrophy of surrounding cortical and subcortical regions. Functional neuroimaging studies in MDD and BPD lend further support to physiological abnormalities in cortical and subcortical Inhibitors,research,lifescience,medical frontolimbic regions. Abnormal regulation of glucose metabolism, regional cerebral blood flow, and high-energy phosphate metabolism are observed in the prefrontal and temporal cortex, basal ganglia, and amygdala, in mood disorders.88 Neuroimaging studies that
examine neurochemical changes in the living brain provide further support for the hypothesis that mood disorders are associated with changes Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical in cell viability and function. For example, high-resolution magnetic resonance spectroscopy in unmedicated subjects with BPD report decreased N-acetylaspartate (NAA) levels bilaterally in the hippocampus89 and in the dorsolateral prefrontal cortex,90 as compared to healthy controls. In contrast, therapeutic doses of lithium increase levels of NAA in the brain of subjects with BPD.91 Such increases in NAA are found in a number of regions including frontal cortex, and are localized almost exclusively in the gray matter. NAA is regarded as a measure of neuronal viability and function, and therefore the changes in NAA levels seen in BPD strongly implicate ADP ribosylation factor alterations in neuronal viability, which may be related to alterations in cell number, cell density, and size, and related volumetric changes. Interestingly, recent magnetic resonance spectroscopic studies of nonhuman primates exposed to early life stressors or repeated stressors also reveal a significant decrease in NAA. The NAA decrease in the animals exposed to repeated stressors was normalized by chronic treatment with the antidepressant tianeptine.