Efficacy and safety of low-dose amisulpride versus olanzapine-fluoxetine combination in post-schizophrenic depression: A randomized controlled trial.

Post-schizophrenic depression (PSD) increases the morbidity, mortality, and health burden in patients with schizophrenia. However, treatment of PSD is challenging due to the lack of substantial evidence of standard clinical practice. This study was aimed at comparing the efficacy and safety of low-dose amisulpride versus olanzapine-fluoxetine combination (OFC) in PSD. This was a randomized controlled trial conducted in sixty patients with PSD fulfilling the eligibility criteria. Recruited patients were randomized to receive either amisulpride at low dose (i.e., 100-300 mg/day) or OFC (5/10 mg + 20 mg) for eight weeks. The Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression-Severity (CGI-S) and serum BDNF levels were assessed at baseline and after eight weeks of treatment. The change in the CDSS scores from baseline over eight weeks was significant in both the amisulpride and OFC groups. However, the changes were not significant when compared between the groups. Similarly, the changes in CGI-S scores and serum BDNF levels were significant in each group; but non-significant between the groups. A significant negative correlation was found between the changes in the CDSS scores and the serum BDNF levels in each group. No significant adverse events were noted in either group. Thus, to conclude, low-dose amisulpride can be a potential monotherapy in PSD with a favourable clinical outcome and safety profile (ClinicalTrials.gov ID: NCT04876521).

Temperature-dependent toxicity of fluoxetine alters the thermal plasticity of marine diatoms.

Anthropogenic activities have led to the emergence of pharmaceutical pollution in marine ecosystems, posing a significant threat to biodiversity in conjunction with global climate change. While the ecotoxicity of human drugs on aquatic organisms is increasingly recognized, their interactions with environmental factors, such as temperature, remain understudied. This research investigates the physiological effects of the selective serotonin reuptake inhibitor (SSRI), fluoxetine, on two diatom species, Phaeodactylum tricornutum and Thalassiosira weissflogii. Results demonstrate that fluoxetine significantly reduces growth rate and biomass production, concurrently affecting pigment contents and the thermal performance curve (TPC) of the diatoms. Fluoxetine reduces the synthesis of chlorophyll a (Chl a) and carotenoid (Car), indicating inhibition of photosynthesis and photoprotection. Furthermore, fluoxetine decreases the maximum growth rate (µmax) while increasing the optimum temperature (Topt) in both species, suggesting an altered thermal plasticity. This shift is attributed to the observed decrease in the inhibition rate of fluoxetine with rising temperatures. These findings emphasize the physiological impacts and ecological implications of fluoxetine on phytoplankton and underscore the significance of considering interactions between multiple environmental drivers when accessing the ecotoxicity of potential pollutants. The present study provides insights into crucial considerations for evaluating the impacts of pharmaceutical pollution on marine primary producers.

Parental exposure to antidepressants has lasting effects on offspring? A case study with zebrafish.

Fish have common neurotransmitter pathways with humans, exhibiting a significant degree of conservation and homology. Thus, exposure to fluoxetine makes fish potentially susceptible to biochemical and physiological changes, similarly to what is observed in humans. Over the years, several studies demonstrated the potential effects of fluoxetine on different fish species and at different levels of biological organization. However, the effects of parental exposure to unexposed offspring remain largely unknown. The consequences of 15-day parental exposure to relevant concentrations of fluoxetine (100 and 1000 ng/L) were assessed on offspring using zebrafish as a model organism. Parental exposure resulted in offspring early hatching, non-inflation of the swimming bladder, increased malformation frequency, decreased heart rate and blood flow, and reduced growth. Additionally, a significant behavioral impairment was also found (reduced startle response, basal locomotor activity, and altered non-associative learning during early stages and a negative geotaxis and scototaxis, reduced thigmotaxis, and anti-social behavior at later life stages). These behavior alterations are consistent with decreased anxiety, a significant increase in the expression of the monoaminergic genes slc6a4a (sert), slc6a3 (dat), slc18a2 (vmat2), mao, tph1a, and th2, and altered levels of monoaminergic neurotransmitters. Alterations in behavior, expression of monoaminergic genes, and neurotransmitter levels persisted until offspring adulthood. Given the high conservation of neuronal pathways between fish and humans, data show the possibility of potential transgenerational and multigenerational effects of pharmaceuticals' exposure. These results reinforce the need for transgenerational and multigenerational studies in fish, under realistic scenarios, to provide realistic insights into the impact of these pharmaceuticals.

The relationship between serum resolvin D1, NLRP3, cytokine levels, and adolescents with first-episode medication-naïve major depressive disorder.

BACKGROUND: Inflammation has become a critical pathological mechanism of Major Depressive Disorder (MDD). NLRP3 is a critical inflammatory pathway to maintain the immune balance. Recently, preclinical evidence showed that Resolvin D1 might potentially offer a new option for antidepressant treatment due to its protective effects through the inhibition of neuroinflammation. However, whether they have clinical value in the diagnosis and treatment evaluation of adolescent depression was unclear. METHODS: Forty-eight untreated first-episode adolescent patients with moderate to severe major depressive disorder, as well as 30 healthy adolescents (HCs, age and gender-matched), were enrolled for this study. Their ages ranged from 13 to 18 (15.75 ± 1.36) years. The patients were treated with fluoxetine for 6-8 weeks. HDRS-17 was used to evaluate the severity of depressive symptoms. Venous blood samples were collected at baseline for the two groups and at the time-point of post-antidepressant treatment for the patients. Serum concentrations of RvD1, NLRP3, IL-1ß, IL-18, and IL-4 were measured by enzyme-linked immunosorbent assays (ELISA) pre- and post-fluoxetine treatment. RESULTS: Serum levels of RvD1 and anti-inflammatory cytokine IL-4 were significantly elevated in adolescents with MDD compared to healthy adolescents, but no significant difference in NLRP3, IL-1ß, and IL-18 between the two groups. Meanwhile, RvD1 (positively) and IL-4 (negatively) were correlated with the severity of symptoms (HDRS-17 scores) after adjusting age, gender, and BMI. Interestingly, fluoxetine treatment significantly reduced the serum levels of RvD1, NLRP3, IL-1ß, and IL-18 in MDD adolescents but increased the levels of IL-4 relative to baseline. Furthermore, we observed that serum levels of RvD1 might be an excellent distinguishing indicator for depression and healthy adolescents. CONCLUSIONS: Our study is the first to compare RvD1 and NLRP3 between adolescent MDD and HCs. Our findings of reactive increase of RvD1 in adolescent MDD comprised a novel and critical contribution. Our results showed the presence of inflammation resolution unbalanced in adolescents with MDD and indicated that RvD1 might be an ideal biomarker for diagnosing and treating adolescent MDD.

Effectiveness of Antidepressants in Combination with Psychotherapy.

BACKGROUND: Consensus-guidelines for prescribing antidepressants recommend that clinicians should be vigilant to match antidepressants to patient's medical history but provide no specific advice on which antidepressant is best for a given medical history. AIMS OF THE STUDY: For patients with major depression who are in psychotherapy, this study provides an empirically derived guideline for prescribing antidepressant medications that fit patients' medical history. METHODS: This retrospective, observational, cohort study analyzed a large insurance database of 3,678,082 patients. Data was obtained from healthcare providers in the U.S. between January 1, 2001, and December 31, 2018. These patients had 10,221,145 episodes of antidepressant treatments. This study reports the remission rates for the 14 most commonly prescribed single antidepressants (amitriptyline, bupropion, citalopram, desvenlafaxine, doxepin, duloxetine, escitalopram, fluoxetine, mirtazapine, nortriptyline, paroxetine, sertraline, trazodone, and venlafaxine) and a category named "Other" (other antidepressants/combination of antidepressants). The study used robust LASSO regressions to identify factors that affected remission rate and clinicians' selection of antidepressants. The selection bias in observational data was removed through stratification. We organized the data into 16,770 subgroups, of at least 100 cases, using the combination of the largest factors that affected remission and selection bias. This paper reports on 2,467 subgroups of patients who had received psychotherapy. RESULTS: We found large, and statistically significant, differences in remission rates within subgroups of patients. Remission rates for sertraline ranged from 4.5% to 77.86%, for fluoxetine from 2.86% to 77.78%, for venlafaxine from 5.07% to 76.44%, for bupropion from 0.5% to 64.63%, for desvenlafaxine from 1.59% to 75%, for duloxetine from 3.77% to 75%, for paroxetine from 6.48% to 68.79%, for escitalopram from 1.85% to 65%, and for citalopram from 4.67% to 76.23%. Clearly these medications are ideal for patients in some subgroups but not others. If patients are matched to the subgroups, clinicians can prescribe the medication that works best in the subgroup. Some medications (amitriptyline, doxepin, nortriptyline, and trazodone) always had remission rates below 11% and therefore were not suitable as single antidepressant therapy for any of the subgroups. DISCUSSIONS: This study provides an opportunity for clinicians to identify an optimal antidepressant for their patients, before they engage in repeated trials of antidepressants. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: To facilitate the matching of patients to the most effective antidepressants, this study provides access to a free, non-commercial, decision aid at http://MeAgainMeds.com. IMPLICATIONS FOR HEALTH POLICIES:  Policymakers should evaluate how study findings can be made available through fragmented electronic health records at point-of-care. Alternatively, policymakers can put in place an AI system that recommends antidepressants to patients online, at home, and encourages them to bring the recommendation to their clinicians at their next visit. IMPLICATIONS FOR FURTHER RESEARCH:  Future research could investigate (i) the effectiveness of our recommendations in changing clinical practice, (ii) increasing remission of depression symptoms, and (iii) reducing cost of care. These studies need to be prospective but pragmatic. It is unlikely random clinical trials can address the large number of factors that affect remission.

Theoretical insights of the pharmaceutical compound fluoxetine in water: Role in direct photolysis and indirect photolysis by free radicals.

The frequent detection of pharmaceutical compounds in the environment has led to a growing awareness, which may pose a major threat to the aquatic environment. In this study, photodegradation (direct and indirect photolysis) of two different dissociation states of fluoxetine (FLU) was investigated in water, mainly including the determination of photolytic transition states and products, and the mechanisms of indirect photodegradation with ·OH, CO3*- and NO3*. The main direct photolysis pathways are defluorination and C-C bond cleavage. In addition, the indirect photodegradation of FLU in water is mainly through the reactions with ·OH and NO3*, and the photodegradation reaction with CO3*- is relatively difficult to occur in the water environment. Our results provide a theoretical basis for understanding the phototransformation process of FLU in the water environment and assessing its potential risk.

The hippocampal salt-inducible kinase 2-CREB-regulated transcription co-activator 1 system mediates the antidepressant actions of paroxetine in mice.

The hippocampal salt-inducible kinase 2 (SIK2)-CREB-regulated transcription co-activator 1 (CRTC1) system has been demonstrated to participate in not only the pathogenesis of depression but also the antidepressant mechanisms of several antidepressant medications including fluoxetine, paroxetine, and mirtazapine. Like fluoxetine, paroxetine is also a widely used selective serotonin (5-HT) reuptake inhibitor (SSRI). Recent studies have indicated that paroxetine also modulates several pharmacological targets other than the 5-HT system. Here, we speculate that paroxetine regulates the hippocampal SIK2-CRTC1 system. Chronic stress models of depression, various behavioral tests, western blotting, co-immunoprecipitation, quantitative real-time reverse transcription PCR, and genetic knockdown were used together in the present study. Our results show that the antidepressant actions of paroxetine in mice models of depression were accompanied by its preventing effects against chronic stress on hippocampal SIK2, CRTC1, and CRTC1-CREB binding. In contrast, genetic knockdown of hippocampal CRTC1 notably abrogated the antidepressant effects of paroxetine in mice. In summary, regulating hippocampal SIK2 and CRTC1 participates in the antidepressant mechanism of paroxetine, extending the knowledge of its pharmacological targets.

Reversible Morphological Remodeling of Prefrontal and Hippocampal Serotonergic Fibers by Fluoxetine.

Serotonin-releasing fibers depart from the raphe nuclei to profusely innervate the entire central nervous system, displaying in some brain regions high structural plasticity in response to genetically induced abrogation of serotonin synthesis. Chronic fluoxetine treatment used as a tool to model peri-physiological, clinically relevant serotonin elevation is also able to cause structural rearrangements of the serotonergic fibers innervating the hippocampus. Whether this effect is limited to hippocampal-innervating fibers or extends to other populations of axons is not known. Here, we used confocal imaging and three-dimensional (3-D) modeling analysis to expand our morphological investigation of fluoxetine-mediated effects on serotonergic circuitry. We found that chronic treatment with a behaviorally active dose of fluoxetine affects the morphology and reduces the density of serotonergic axons innervating the medial prefrontal cortex, a brain region strongly implicated in the regulation of depressive- and anxiety-like behavior. Axons innervating the somatosensory cortex were unaffected, suggesting differential susceptibility to serotonin changes across cortical areas. Importantly, a 1-month washout period was sufficient to reverse morphological changes in both the medial prefrontal cortex and in the previously characterized hippocampus, as well as to normalize behavior, highlighting an intriguing relationship between axon density and an antidepressant-like effect. Overall, these results further demonstrate the bidirectional plasticity of defined serotonergic axons and provide additional insights into fluoxetine effects on the serotonergic system.

Nanoplastics increase in vitro oestrogenic activity of neurotherapeutic drugs.

Environmental pollution with plastic nanoparticles (PNPs) has rendered hazard assessment of unintentional human exposure to neurotherapeutic drugs through contaminated water and food ever more complicated. Due to their small size, PNPs can easily enter different cell types and cross different biological barriers, while their high surface-to-volume ratio enables higher adsorption of chemicals. This is how PNPs take the role of a Trojan horse as they enhance bioaccumulation of many different pollutants. One of the health concerns related to water pollution with neurotherapeutic drugs is endocrine disruption, already evidenced for the anticonvulsant drug carbamazepine (Cbz) and antidepressant fluoxetine (Flx). Our study aimed to evaluate endocrine disrupting effects of Cbz and Flx in mixtures with polystyrene nanoparticles (PSNPs) using the in vitro luciferase assay to measure oestrogen receptor activity in T47D-KBluc cells treated with Cbz-PSNPs or Flx-PSNPs mixtures and compare it with the activities observed in cells treated with individual mixture components (Cbz, Flx, or PSNPs). Dose ranges used in the study were 0.1-10 mg/L, 1-100 µmol/L, and 0.1-10 µmol/L for PSNPs, Cbz, and Flx, respectively. Our findings show that none of the individual components activate oestrogen receptors, while the mixtures induce oestrogen receptor activity starting with 0.1 mg/L for PSNPs, 10 µmol/L for Cbz, and 0.5 µmol/L for Flx. This is the first study to evidence that PSNPs increase oestrogen receptor activity induced by neurotherapeutic drugs at their environmentally relevant concentrations and calls for urgent inclusion of complex mixtures in health hazard assessments to inform regulatory response.

Prenatal Fluoxetine Exposure Influences Glucocorticoid Receptor-Mediated Activity in the Prefrontal Cortex of Adolescent Rats Exposed to Acute Stress.

Any deviation from the programmed processes of brain development may modify its formation and functions, thereby precipitating pathological conditions, which often become manifest in adulthood. Exposure to a challenge during crucial periods of vulnerability, such as adolescence, may reveal molecular changes preceding behavioral outcomes. Based on a previous study showing that prenatal fluoxetine (FLX) leads to the development of an anhedonic-like behavior in adult rats, we aimed to assess whether the same treatment regimen (i.e., fluoxetine during gestation; 15 mg/kg/day) influences the ability to respond to acute restraint stress (ARS) during adolescence. We subjected the rats to a battery of behavioral tests evaluating the development of various phenotypes (cognitive deficit, anhedonia, and anxiety). Furthermore, we carried out molecular analyses in the plasma and prefrontal cortex, a brain region involved in stress response, and whose functions are commonly altered in neuropsychiatric conditions. Our findings confirm that prenatal manipulation did not affect behavior in adolescent rats but impaired the capability to respond properly to ARS. Indeed, we observed changes in several molecular key players of the hypothalamic pituitary adrenal axis, particularly influencing genomic effects mediated by the glucocorticoid receptor. This study highlights that prenatal FLX exposure influences the ability of adolescent male rats to respond to an acute challenge, thereby altering the functionality of the hypothalamic-pituitary-adrenal axis, and indicates that the prenatal manipulation may prime the response to challenging events during this critical period of life.

Quercetin attenuates brain apoptosis in mice with chronic unpredictable mild stress-induced depression.

BACKGROUND: Depression is a common psychiatric disorder with limited effective treatments. Research suggests that depression involves apoptosis mechanisms. Quercetin (QUE) has been reported to have anti-apoptotic activities. In this study, we aimed to investigate the effects and mechanisms of QUE in chronic unpredictable mild stress (CUMS)-induced depression. METHODS: After establishing mouse models of CUMS-induced depression, the mice were randomly assigned into four groups: control, CUMS, CUMS+QUE, and CUMS+Fluoxetine (FLX). The body weight of the mice was measured during the study. Then, depression-associated behaviors were evaluated using the sucrose preference test (SPT), novelty suppressed feeding test (NSFT), forced swim test (FST) and tail suspension test (TST). Apoptosis in the hippocampus and prefrontal cortex was determined using flow cytometry. Bcl-2 and Nrf2 protein expressions in the hippocampus and prefrontal cortex were also detected. Furthermore, Western blot was used to measure the protein levels of p-ERK, ERK, p-CREB, CREB, and Nrf2 in brain tissues. RESULTS: QUE or FLX administration increased the body weight of the CUMS mice. Behavioral tests indicated that CUMS mice developed a state of depression, but QUE or FLX treatment improved their depression-associated behaviors. Meanwhile, QUE or FLX treatment decreased apoptosis in the hippocampus and prefrontal cortex. Furthermore, the decreased Nrf2 protein expression, ERK and CREB phosphorylation in CUMS group were enhanced by QUE or FLX administration. CONCLUSION: QUE could attenuate brain apoptosis in mice with CUMS-induced depression, and the mechanism may be related to the ERK/Nrf2 pathway, indicating that QUE could be a potential treatment for depression.

The risk of acute infections in new users of antidepressants: An observational cohort study.

BACKGROUND: Preclinical studies suggested that drugs that functionally inhibit acid sphingomyelinase (FIASMA)may enhance immune cell longevity and potentially offer protection against infections. Many antidepressants have shown FIASMA activity. METHODS: We conducted a cohort study using primary-care data from the UK-based Clinical Practice Research Datalink (2000-2021). We assessed the association of composite diagnosed acute infections in new users of fluoxetine, sertraline, paroxetine, or venlafaxine aged 18-80 years compared to citalopram. We compared SARS-CoV-2 infections between groups in a secondary analysis. We estimated incidence rates (IR) and IR ratios (IRR) of acute infections in four pairwise comparisons using negative binomial regression. We applied propensity score (PS) fine stratification to control for confounding. RESULTS: In the PS-weighted cohorts, we included 353,138 fluoxetine, 222,463 sertraline, 69,963 paroxetine, 32,608 venlafaxine, and between 515,996 and 516,583 new citalopram users. PS-weighted IRs ranged between 76.8 acute infections /1000 person-years (py) (sertraline) and 98.9 infections/1000 py (citalopram). We observed PS-weighted IRRs around unity for paroxetine (0.97, 95 % CI, 0.95-1.00), fluoxetine (0.94, 95 % CI, 0.92-0.95), and venlafaxine (0.90, 95 % CI, 0.87-0.94) vs citalopram. Reduced IRR for sertraline vs citalopram (0.84, 95 % CI, 0.82-0.85), became null within subgroups by cohort entry date. In the analysis of SARS-CoV-2 infection, no statistically relevant risk reduction was seen. LIMITATIONS: Analysis not limited to patients with diagnosed depression, possible underestimation of infection incidence, and unclear FIASMA activity of citalopram. CONCLUSIONS: Fluoxetine, sertraline, paroxetine, and venlafaxine were not associated with a reduced risk of acute infection when compared with the presumably weak FIASMA citalopram.

Psychoactive substance consumption after the Fundão dam mine tailing disaster in Minas Gerais State, Brazil.

Disasters cause changes in morbidity, mortality, and medicine use. Brazil is one of the main producers of mineral ores at great environmental cost. Mine tailings are stored in dams and ruptures have led to major disasters. We investigated the consumption of psychoactive medicines in the municipalities affected by the Fundão dam disaster in Minas Gerais State. An ecological study was carried out on drug consumption, estimated using public purchases in Minas Gerais and dispensing data from private retail pharmacies. Consumption (in number of defined daily doses/100,000 inhabitants per day) was analyzed descriptively in eight municipalities, stratified according to consumption level during a 25-month period. Six comparisons of mean consumption values for both data sets were done for pre- and post-disaster periods. The means of medicine consumption before and after the event were plotted and linear trends were added. Public purchase data evinced high consumption levels. Only pharmaceutical retail showed significant differences between the strata in the pre-disaster versus two post-disaster periods. Smaller municipalities showed an increase in consumption 15 months after the disaster. Clonazepam led the way in pharmaceutical retail consumption, followed by fluoxetine. Medicines showed an upward trend after the disaster. The high public provision may have stifled significant consumption patterns of psychoactive drugs; however, peak consumption were observed in private retail, suggesting a modification in use patterns after the disaster. The decrease in consumption immediately after the event was probably related to lower care-seeking behavior on the part of the population, and significant peaks after the disaster may reflect economic consequences of it.

Antidepressant fluoxetine alleviates colitis by reshaping intestinal microenvironment.

BACKGROUND: The impact of antidepressants on Inflammatory bowel diseases (IBD) has been extensively studied. However, the biological effects and molecular mechanisms of antidepressants in alleviating colitis remain unclear. METHODS: We systematically assessed how antidepressants (fluoxetine, fluvoxamine and venlafaxine) affected IBD and chose fluoxetine, the most effective one, for mechanism studies. We treated the C56BL/6 mice of the IBD model with fluoxetine and their controls. We initially assessed the severity of intestinal inflammation in mice by body weight loss, disease Activity Index scores and the length of the colon. The H&E staining and immunohistochemical staining of MUC2 of colon sections were performed to observe the pathological changes. RT-qPCR and western blot were conducted to assess the expression level of the barrier and inflammation-associated genes. Then, single-cell RNA sequencing was performed on mouse intestinal mucosa. Seurat was used to visualize the data. Uniform Manifold Approximation and Projection (UMAP) was used to perform the dimensionality reduction. Cell Chat package was used to perform cell-cell communication analysis. Monocle was used to conduct developmental pseudotime analysis. Last, RT-qPCR, western blot and immunofluorescence staining were conducted to test the phenomenon discovered by single-cell RNA sequencing in vitro. RESULTS: We found that fluoxetine treatment significantly alleviated colon inflammation. Notably, single-cell RNA sequencing analysis revealed that fluoxetine affected the distribution of different cell clusters, cell-cell communication and KEGG pathway enrichment. Under the treatment of fluoxetine, enterocytes, Goblet cells and stem cells became the dominating cells. The pseudotime analysis showed that there was a trend for M1 macrophages to differentiate into M2 macrophages. Lastly, we tested this phenomenon in vitro, which exhibited anti-inflammatory effects on enterocytes. CONCLUSIONS: Fluoxetine exhibited anti-inflammatory effects on intestinal mucosa via remodeling of the intestinal cells and macrophages, which reveals that fluoxetine is a promising therapeutic drug for the treatment of IBD and psychiatric comorbidities.

[Modulating gut microbiota improves neurological function and depressive symptoms in rats with post-stroke depression].

OBJECTIVE: To evaluate the effect of modulating gut microbiota for improving brain injury in rats with post-stroke depression. METHODS: Adult SD rats were randomized into normal control, middle cerebral artery occlusion (MCAO), post-stroke depression (PSD), PSD with fecal transplantation, PSD with antibiotics (rifaximin), PSD with probiotics (lactobacilli), and PSD with fluoxetine treatment groups (n=9). Neurological function scores of the rats were determined, and the changes in sugar water preference and immobility time in forced swimming test were observed; plasma levels of trimethylamine N-oxide (TMAO) and hydrogen sulfide (H2S) were detected with ELISA, Occludin, and the expressions of occludin, caudin-5 and IgG proteins Ⅰ the brain tissues were determined using Western blotting. RESULTS: Compared with those in the control group, the rats in MCAO and PSD groups had significantly increased neurological function scores, TMAO level, the ratio of TMAO/H2S, and immobility time in forced swimming test with a lowered level of H2S (P < 0.05). These changes were more obvious in PSD rats, which also exhibited a reduced sugar water preference with increased IgG protein and decreased occluding and caudin-5 expressions in the brain tissue (P < 0.05). TMAO/H2S ratio in PSD rats was positively correlated with neurological function score (R2=0.3235, P=0.0269) and immobility time in swimming (R2=0.6290, P=0.0004) and negatively with sugar water preference (R2=-0.4534, P=0.0059). Treatment with fecal transplantation, antibiotics, probiotics and fluoxetine all significantly reduced neurological function scores, immobility time in forced swimming, TMAO/H2S ratio, and IgG protein expression and increased sugar water preference and brain occludin and caudin-5 expressions of the PSD rats (P < 0.05). CONCLUSION: In PSD rats, TMAO/H2S ratio is correlated with neurological function score, immobility time in forced swimming and sugar water preference, and modulating intestinal flora can improve neurological function and depressive symptoms and improve the integrity of the blood-brain barrier.

Fluoxetine attenuates stress-induced depression-like behavior due to decrease in pro-inflammatory cytokines in male rats.

Background: Pro-inflammatory cytokines are implicated in depression caused by both environmental- and alcohol-induced stress. The purpose of the study was to investigate the cytokine levels in serum and hippocampus following induction of depression-like behaviors (DLB) by either forced swimming test (FST) or ethanol-induced DLB (EID). We also investigated the effect of prior administration of antidepressant drug fluoxetine on cytokines in animals exposed to both models of DLB. Methods: Animals were pretreated with fluoxetine before inducing DLB, while DLB was induced in some animals using FST and ethanol in different groups of rats without fluoxetine pretreatment. The ELISA was used to detect changes in cytokine (IL-1ß, IL-6, and TNF-α) levels in serum and hippocampus. Results: The mean levels of IL-1ß and IL-6 measured in serum and hippocampus were significantly higher in FST and EID models when compared to the control group. The serum concentrations of IL-1ß and IL-6 were significantly reduced in animals pre-treated with 5 mg/kg and 10 mg/kg of fluoxetine in both FST and EID models when compared to the untreated FST and EID groups respectively. Conclusions: In conclusion, both environment and alcohol can induce stress and DLB in rats with similar intensity, and their mechanisms of DLB induction involve activation of pro-inflammatory cytokines. Moreover, fluoxetine can prevent stress-induced inflammation in models of DLB.

Involvement of the GABAA Receptor in the Antidepressant-Like Effects Produced by Low and High Doses of the Flavonoid Chrysin in the Rat: A Longitudinal Study.

BACKGROUND: The flavonoid chrysin produces rapid and long-lasting anxiolytic- and antidepressant-like effects in rats. However, it is not known whether low and high doses of chrysin produce differential anti-immobility effects through the Gamma-Aminobutyric Acid sub-type A (GABAA) receptor. The goal of this work was therefore to compare low and high doses of chrysin for their effects on depression-like behavior in a longitudinal study. Moreover, chrysin was compared with the serotonergic fluoxetine and Gamma-Aminobutyric Acid (GABA)ergic allopregnanolone, and its involvement with the GABAA receptor after chronic treatment was also investigated. METHODS: Male Wistar rats were assigned to five groups (n = 8 each): vehicle, 1 mg/kg chrysin, 5 mg/kg chrysin, 1 mg/kg fluoxetine, and 1 mg/kg allopregnanolone. In the first experiment, treatments were injected daily and the effects on locomotor activity and the forced swim test were evaluated at 0, 1, 14, and 28 days of treatment, and 48 h after the final treatment. In the second experiment, similar groups were treated for 28 days with injection of 1 mg/kg picrotoxin to investigate the role of the GABAA receptor. Depending on the experimental design, one- and two-way analysis of variance (ANOVA) tests were used for statistical analysis, with p < 0.05 set as the criteria for significance. RESULTS: In both experiments, the treatments did not alter locomotor activity. However, low and high doses of chrysin, allopregnanolone, and fluoxetine gradually produced antidepressant-like effects in the forced swim test, and maintained this effect for 48 h post-treatment, except with low dose chrysin. Picrotoxin blocked the antidepressant-like effects produced by low dose chrysin, but did not affect those produced by high dose chrysin, allopregnanolone, or fluoxetine. CONCLUSIONS: The differential antidepressant-like effects caused by low and high doses of chrysin are time-dependent. Low dose chrysin produces a rapid antidepressant-like effect, whereas high dose chrysin produces a delayed but sustained the effect, even 48 h after withdrawal. The effect with high dose chrysin was similar to that observed with allopregnanolone and fluoxetine. The mechanism for the antidepressant-like effect of low chrysin appears to be GABAergic, whereas the effect of high dose chrysin may involve other neurotransmission and neuromodulation systems related to the serotonergic system.

Prebiotics modulate the microbiota-gut-brain axis and ameliorate anxiety and depression-like behavior in HFD-fed mice.

Previous research has demonstrated that Prebiotics can influence the composition of the gut microbiota, consequently impacting mood regulation. This study aimed to assess the effects of Prebiotics, specifically Fructooligosaccharides (FOS) and Galactooligosaccharides (GOS) on neuroinflammation, depression, and anxiety-like behavior in a mouse model fed a high-fat diet (HFD). Initially, mice were divided into two groups: a control group on a standard diet (n = 15) and a group on an HFD for 18 weeks (n = 45). By the 13th week, the HFD group was further divided into experimental groups: Control (n = 15), HFD (n = 15), HFD receiving Prebiotics (n = 15), and HFD receiving Fluoxetine (n = 15). From the 13th week onward, the HFD + Prebiotics group received both the high-fat diet and a combination of FOS and GOS, while the HFD + Fluoxetine group received Fluoxetine in their drinking water. In the 18th week, all mice underwent tests to evaluate behavior, including the Tail Suspension Test (TST), Forced Swimming Test (FST), Sucrose Preference Test (SPT), and the Plus Maze Test (PMT), after which they were euthanized. Mice on the HFD exhibited increased body weight, abdominal size, blood glucose, triglyceride levels, cholesterol, insulin, HOMA index, and higher serum IL-1ß. These obese mice also displayed an increased number of microglia and astrocytes, activation of the TLR4 pathway, and elevated levels of neuroinflammatory markers like TNF-α, IL-1ß, and COX-2. Moreover, obese mice showed increased activation of the IDO pathway and decreased levels of NMDA receptors. Additionally, markers of neurogenesis and synaptic plasticity, such as PSD, SAP 102, CREB-p, and BDNF, were lower. Treatment with FOS and GOS reversed symptoms of depression and anxiety in mice subjected to HD. This improvement in behavior resulted from a reduction in dysbiosis with an increase in acetate-producing bacteria (B. acidifaciens and B. dorei) and intestinal permeability, leading to a decrease in chronic peripheral and central inflammation. Furthermore, the modulation of the gut-brain axis by FOS and GOS promoted elevated acetate and GPR43 levels in the brain and a reduction in the levels of pro-inflammatory cytokines, positively impacting signaling pathways of neuronal proliferation and survival in the hippocampus and prefrontal cortex.

Neonatal hypoxia impairs serotonin release and cognitive functions in adult mice.

Children who experienced moderate perinatal asphyxia (MPA) are at risk of developing long lasting subtle cognitive and behavioral deficits, including learning disabilities and emotional problems. The prefrontal cortex (PFC) regulates cognitive flexibility and emotional behavior. Neurons that release serotonin (5-HT) project to the PFC, and compounds modulating 5-HT activity influence emotion and cognition. Whether 5-HT dysregulations contribute to MPA-induced cognitive problems is unknown. We established a MPA mouse model, which displays recognition and spatial memory impairments and dysfunctional cognitive flexibility. We found that 5-HT expression levels, quantified by immunohistochemistry, and 5-HT release, quantified by in vivo microdialysis in awake mice, are reduced in PFC of adult MPA mice. MPA mice also show impaired body temperature regulation following injection of the 5-HT1A receptor agonist 8-OH-DPAT, suggesting the presence of deficits in 5-HT auto-receptor function on raphe neurons. Finally, chronic treatment of adult MPA mice with fluoxetine, an inhibitor of 5-HT reuptake transporter, or the 5-HT1A receptor agonist tandospirone rescues cognitive flexibility and memory impairments. All together, these data demonstrate that the development of 5-HT system function is vulnerable to moderate perinatal asphyxia. 5-HT hypofunction might in turn contribute to long-term cognitive impairment in adulthood, indicating a potential target for pharmacological therapies.