Sertraline reduces glutamate uptake in human platelets

Sertraline associated with gold nanoparticles reduce cellular toxicity and induce sex-specific responses in behavior and neuroinflammation biomarkers in a mouse model of anxiety

This study aimed to evaluate the effects of sertraline associated with gold nanoparticles (AuNPs) in vitro cell viability and in vivo behavior and inflammatory biomarkers in a mouse model of anxiety. Sertraline associated with AuNPs were synthesized and characterized. For the in vitro study, NIH3T3 and HT-22 cells were treated with different doses of sertraline, AuNPs, and sertraline + AuNPs and their viability was evaluated using the MTT assay. For the in vivo study, pregnant Swiss mice were administered a single dose of lipopolysaccharide (LPS) on the ninth day of gestation. The female and male offspring were divided into five treatment groups on PND 60 and administered chronic treatment for 28 days. The animals were subjected to behavioral testing and were subsequently euthanized. Their brains were collected and analyzed for inflammatory biomarkers. Sertraline associated with AuNPs exhibited significant changes in surface characteristics and increased diameters. Different doses of sertraline + AuNPs showed higher cell viability in NIH3T3 and HT-22 cells compared with sertraline alone. The offspring of LPS-treated dams exhibited anxiety-like behavior and neuroinflammatory biomarker changes during adulthood, which were ameliorated via sertraline + AuNPs treatment. The treatment response was sex-dependent and brain region-specific. These results suggest that AuNPs, which demonstrate potential to bind to other molecules, low toxicity, and reduced inflammation, can be synergistically used with sertraline to improve drug efficacy and safety by decreasing neuroinflammation and sertraline toxicity.

Different Effects of SSRIs, Bupropion, and Trazodone on Mitochondrial Functions and Monoamine Oxidase Isoform Activity

Mitochondrial dysfunction is involved in the pathophysiology of psychiatric and neurodegenerative disorders and can be used as a modulator and/or predictor of treatment responsiveness. Understanding the mitochondrial effects of antidepressants is important to connect mitochondria with their therapeutic and/or adverse effects. Pig brain-isolated mitochondria were used to evaluate antidepressant-induced changes in the activity of electron transport chain (ETC) complexes, monoamine oxidase (MAO), mitochondrial respiratory rate, and ATP. Bupropion, escitalopram, fluvoxamine, sertraline, paroxetine, and trazodone were tested. All tested antidepressants showed significant inhibition of complex I and IV activities at high concentrations (50 and 100 µmol/L); complex II + III activity was reduced by all antidepressants except bupropion. Complex I-linked respiration was reduced by escitalopram >> trazodone >> sertraline. Complex II-linked respiration was reduced only by bupropion. Significant positive correlations were confirmed between complex I-linked respiration and the activities of individual ETC complexes. MAO activity was inhibited by all tested antidepressants, with SSRIs causing a greater effect than trazodone and bupropion. The results indicate a probable association between the adverse effects of high doses of antidepressants and drug-induced changes in the activity of ETC complexes and the respiratory rate of mitochondria. In contrast, MAO inhibition could be linked to the antidepressant, procognitive, and neuroprotective effects of the tested antidepressants.

Analysis of neurotransmitters in Daphnia magna affected by neuroactive pharmaceuticals using liquid chromatography-high resolution mass spectrometry

Neurotransmission plays an essential role during the central nervous system (CNS) development. During the last years, several studies based on the changes produced in neurotransmitters of aquatic organisms caused by pharmaceuticals have been reported. Daphnia magna, the aquatic ecotoxicological model organism, shares several of the neurotransmitters targeted by antidepressant and other neuro-active drugs with vertebrates. Therefore, a method based on liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) has been applied for the first time to study the levels of 41 neurotransmitters in Daphnia magna under the effect of four different neuro-active pharmaceuticals (sertraline, venlafaxine, duloxetine and fluoxetine). In addition, the performance of LC-HRMS was studied in terms of linearity, sensitivity, intra- and inter-day precision, and overall robustness. The developed analytical method using LC-HRMS is a new tool for neurotoxicology research using the Daphnia magna model. As a result, general differences on the concentrations of those neurotransmitters exposed to the mentioned pharmaceuticals were observed.

Can a Selective Serotonin Reuptake Inhibitor Act as a Glutamatergic Modulator?

Sertraline (Zoloft) and fluoxetine (Prozac) are selective serotonin reuptake inhibitors whose antidepressant mechanism of action is classically attributed to an elevation of the extracellular levels of serotonin in the synaptic cleft. However, the biological effects of these drugs seem to be more complex than their traditionally described mechanism of action. Among their actions is the inhibition of different types of Na⁺ and K⁺ channels, as well as of glutamate uptake activity. The clearance of extracellular glutamate is essential to maintain the central nervous system within physiological conditions, and this excitatory neurotransmitter is removed from the synaptic cleft by astrocyte transporters. This transport depends upon a hyperpolarized membrane potential in astrocytes that is mainly maintained by Kir4.1 K⁺ channels. The impairment of the Kir4.1 channel activity reduces driving force for the glutamate transporter, resulting in an accumulation of extracellular glutamate. It has been shown that sertraline and fluoxetine inhibit Kir4.1 K⁺ channels. Recently, we demonstrated that sertraline reduces glutamate uptake in human platelets, which contain a high-affinity Na⁺-dependent glutamate uptake system, with kinetic and pharmacological properties similar to astrocytes in the central nervous system. Considering these similarities between human platelets and astrocytes, one might ask if sertraline could potentially reduce glutamate clearance in the synaptic cleft and consequently modulate glutamatergic transmission. This possibility merits investigation, since it may provide additional information regarding the mechanism of action and perhaps the side effects of these antidepressants.

Sertraline Induces Toxicity and Behavioral Alterations in Planarians

Toxicity attributed to sertraline has been demonstrated recently in different cell types and also in some organisms. We investigated the effect of sertraline on planarians, which are considered suitable for investigations in neurotoxicology and currently are widely used as an animal model in neuropharmacological studies. Planarians treated with 10 µM sertraline showed a rapid reduction in their spontaneous movement until they became completely motionless and then showed a series of asynchronous paroxysms (seizures) followed by progressive tissue damage, beginning 48 h after the sertraline treatment, and died approximately 72 h later. Our data showed that sertraline does not cause planarian death within the range of therapeutic concentrations; however, behavioral alterations were observed with concentrations that can be considered compatible with therapeutic ones, such as a significant reduction in planarian locomotory activity at 0.4 µM. Treatment with 4 µM sertraline had a significant effect, reducing planarian locomotory activity and increasing the number of asynchronous paroxysms; both effects were significantly maintained even 24 h after the sertraline was withdrawn. These behavioral changes observed at low micromolar concentrations suggest that sertraline might have residual biological consequences for planarians, even after it is withdrawn.