Seasonal factors, such as daily amount of sunshine and global radiation, influence serotonin-1A receptor binding in limbic brain regions of healthy human subjects. Combined with recently demonstrated seasonal fluctuations in the serotonin transporter availability, our results underline the importance of seasonal factors in the regulation of the serotonergic transmission.
Background:Drug-induced liver injury is a common cause of liver damage and the most frequent reason for withdrawal of a drug in the United States. The symptoms of drug-induced liver damage are extremely diverse, with some patients remaining asymptomatic.Methods:This observational study is based on data of Arzneimittelsicherheit in der Psychiatrie, a multicenter drug surveillance program in German-speaking countries (Austria, Germany, and Switzerland) recording severe drug reactions in psychiatric inpatients. Of 184234 psychiatric inpatients treated with antidepressants between 1993 and 2011 in 80 psychiatric hospitals, 149 cases of drug-induced liver injury (0.08%) were reported.Results:The study revealed that incidence rates of drug-induced liver injury were highest during treatment with mianserine (0.36%), agomelatine (0.33%), and clomipramine (0.23%). The lowest probability of drug-induced liver injury occurred during treatment with selective serotonin reuptake inhibitors ([0.03%), especially escitalopram [0.01%], citalopram [0.02%], and fluoxetine [0.02%]). The most common clinical symptoms were nausea, fatigue, loss of appetite, and abdominal pain. In contrast to previous findings, the dosage at the timepoint when DILI occurred was higher in 7 of 9 substances than the median overall dosage. Regarding liver enzymes, duloxetine and clomipramine were associated with increased glutamat-pyruvat-transaminase and glutamat-oxalat-transaminase values, while mirtazapine hardly increased enzyme values. By contrast, duloxetine performed best in terms of gamma-glutamyl-transferase values, and trimipramine, clomipramine, and venlafaxine performed worst.Conclusions:Our findings suggest that selective serotonin reuptake inhibitors are less likely than the other antidepressants, examined in this study, to precipitate drug-induced liver injury, especially in patients with preknown liver dysfunction.
Dysregulation of the hypothalamic-pituitary-adrenocortical axis with deficient glucocorticoid feedback and alterations in the serotonergic system have been identified as biological correlates of mood disorders. Close examination of the interaction between these systems may offer insights into the pathophysiology of anxiety disorders and depression to understand how stress and these disorders are related. In this study, we investigated the relationship between plasma levels of cortisol and the dominant inhibitory serotonergic receptor, serotonin-1A (5-HT1A). Using positron emission tomography (PET) and the radioligand [carbonyl-11C]WAY-100635, we quantified the 5-HT1A receptor binding. Data from 12 male patients with social phobia and 18 matched control subjects were analysed. Seven brain regions were investigated: the anterior and posterior cingulate cortices, hippocampus, amygdala, medial orbitofrontal and retrosplenial cortices, and dorsal raphe nucleus. Partial correlation analysis, controlled for age and radiochemical variables, was performed to demonstrate the association between cortisol plasma levels and 5-HT1A receptor binding. Cortisol plasma levels were significantly lower in patients with social phobia compared to healthy controls. Moreover, we found strong negative correlations between cortisol plasma levels and 5-HT1A binding in the amygdala (r=-0.93, p=0.0004), hippocampus (r=-0.80, p=0.009), and retrosplenial cortex (r=-0.48, p=0.04) in patients with social phobia. Within the former two regions, these associations were significantly higher in patients than in healthy controls. This PET study confirms a negative association between plasma cortisol levels and the 5-HT1A receptor distribution consistent with studies in rodents and non-human primates. Dysregulation of the cortisol level might increase the vulnerability for mood disorders by altering limbic 5-HT1A receptors.
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