Monoamine depletion studies: implications for antidepressant discontinuation syndrome.
ABSTRACT The likelihood of a connection between serotonin reuptake inhibitor (SRI) discontinuation and an acute reduction in synaptic serotonin (5-HT) has ignited interest in the similarities between SRI discontinuation syndrome and the symptoms observed after acute tryptophan depletion, which reduces synaptic 5-HT levels. An open question is whether these 2 phenomena have shared characteristics because of a similar underlying mechanism. The evidence in support of a similar underlying mechanism includes the observation that comparable proportions of SRI-treated patients experience depressive symptoms following tryptophan depletion and SRI discontinuation. Furthermore, the proportion of people who have emotional changes with rapid antidepressant discontinuation may be parallel to the proportion of people who experience those changes with rapid tryptophan depletion.
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ABSTRACT: Xiao Yao San (XYS) is a classical Chinese medicine formula that has been widely used to treat mood disorders for hundreds of years. To confirm the effect of XYS and better understand its underlying mechanism, high-performance liquid chromatography-mass spectrometry analysis-based quality control of XYS extracts and proteomics-based identification of differential proteins in the hippocampus were adopted in social isolation and chronic unpredictable mild stress- (CUMS-) treated rats. The depressive-like behavior of rats induced by CUMS resembled the manifestation of human depression. The upregulated corticosterone (CORT) and urocortin 2 (UCN2) levels demonstrated the existence of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity. XYS was effective in ameliorating the depressive-like behavior and downregulating UCN2 and CORT. XYS decreased the expression of serine/threonine-protein phosphatase 2A subunit B and increased the expression of β-arrestin 2. The expressions of brain-derived neurotrophic factor (BDNF), tyrosine receptor kinase B (TrkB), and mammalian target of rapamycin (mTOR) were also elevated by XYS. In conclusion, XYS improves social isolation and CUMS-induced depressive-like behavior and ameliorates HPA hyperactivation through the downregulation of corticotrophin releasing hormone (CRH) receptor 2. The upregulation of BDNF/TrkB and the phosphorylation of mTOR require β-arrestin 2 as a scaffold to regulate stress signaling.Evidence-based Complementary and Alternative Medicine 01/2014; 2014:902516. · 2.18 Impact Factor
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ABSTRACT: Glucocorticoids can cause depression and anxiety. Mechanisms for glucocorticoid effects on mood are largely undefined. The dorsal raphé nucleus (DRN) produces the majority of serotonin in the brain, and expresses glucocorticoid receptors (GR). Because we previously showed that antidepressants used to treat depression and anxiety decrease DRN GR expression, we hypothesized that deleting DRN GR would have anxiolytic- and antidepressant-like effects. We also hypothesized that DRN GR deletion would disinhibit activity of the hypothalamic–pituitary–adrenal (HPA) axis. Adeno-associated virus pseudotype AAV2/9 expressing either Cre recombinase (DRNGRKO mice) or GFP (DRN-GFP mice) was injected into the DRN of floxed GR mice to test these hypotheses. Three weeks after injection, mice underwent 21 days of social defeat or control handling and were tested for anxiety-like behavior (open-field test, elevated-plus maze), depression-like behavior [sucrose preference, forced-swim test (FST), tail-suspension test (TST)], social interaction, and circadian and stress-induced HPA activity. DRN GR deletion decreased anxiety-like behavior in control but not in defeated mice. DRN GR deletion decreased FST and tended to decrease TST despair-like behavior in both control and defeated mice, but did not affect sucrose preference. Exploration of social (a novel mouse) as well as neutral (an empty box) targets was increased in DRNGRKO mice, suggesting that DRN GR deletion also promotes active coping. DRN GR deletion increased stress-induced HPA activity without strongly altering circadian HPA activity. We have shown a novel role for DRN GR to mediate anxiety- and despair-like behavior and to regulate HPA negative feedback during acute stress.European Journal of Neuroscience 03/2014; · 3.67 Impact Factor
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ABSTRACT: Discontinuation symptoms are described for almost all major groups of antidepressants. Crucial differences between discontinuation symptoms and symptoms after withdrawal of benzodiazepines are pointed out. Furthermore, it is important to discern from relapse of depression in order to manage the symptoms in primary care where the use of selective serotonin re-uptake inhibitors (SSRI) is substantial. In this paper we inform of the key symptoms after SSRI, present tools for understanding and recognizing the condition and suggest initiatives to manage it rationally.Ugeskrift for laeger 02/2014; 176(3):231-235.