Efficacy of antidepressants in the treatment of chronic nonspecific low back pain: a systematic review and meta-analysis.

Aim: This study reassesses the efficacy and safety of antidepressants in treating nonspecific chronic low back pain (NCLBP).Materials & methods: A systematic review was conducted following PRISMA guidelines, including randomized clinical trials (RCTs) from PubMed, Embase, Scopus, LILACS, SciELO and Cochrane CENTRAL, published through August 2024. Studies compared antidepressants with placebo or active comparators. The primary outcomes were pain relief and quality of life. Protocol registration: www.crd.york.ac.uk/prospero identifier is CRD42023307516.Results: Nine RCTs involving 1758 patients were analyzed. The antidepressants examined included duloxetine, escitalopram, bupropion, amitriptyline, imipramine and desipramine. Duloxetine 60 mg significantly reduced pain (MD = -0.57; 95% CI = -0.78 to -0.36) and improved quality of life compared with placebo, with side effects that were generally tolerable. Notably, higher doses of duloxetine (120 mg) were associated with an increase in adverse events. However, other antidepressants like amitriptyline and escitalopram demonstrated only modest or inconsistent effects.Conclusion: Duloxetine at 60 mg provides consistent pain relief and improves the quality of life in NCLBP, but higher doses increase adverse events. Escitalopram might offer modest benefits but should be considered a third-line treatment. Other antidepressants, such as amitriptyline, bupropion, imipramine and desipramine, have limited evidence supporting their efficacy and are associated with adverse effects.

Chronic lower back pain is a condition that persists for a long time and can be difficult to manage. While the exact cause isn't always clear, it affects many people and can be difficult to manage. Doctors sometimes prescribe antidepressants, which are typically used for treating depression, but they may also help to reduce pain by influencing how the brain processes it.In this paper, we examined several studies to determine whether these antidepressants are effective in treating chronic lower back pain. We analyzed nine studies involving 1758 participants who were treated with different medications: bupropion, duloxetine, escitalopram, amitriptyline, imipramine and desipramine.Among these medications, duloxetine stood out as the most effective. It not only helped to relieve pain but also improved the participants' ability to carry out daily activities. Additionally, duloxetine had fewer side effects than some of the other medications, although it can still cause mild issues such as nausea.In conclusion, duloxetine appears to be a promising option for managing chronic lower back pain, as long as the appropriate dosage is used to balance pain relief and side effects.

The Antidepressant- and Anxiolytic-Like Effects of the Phosphodiesterase Type-5 Inhibitor Tadalafil are Associated with the Modulation of the Gut-Brain Axis During CNS Autoimmunity.

Multiple Sclerosis (MS) is a debilitating disease that severely affects the central nervous system (CNS). Apart from neurological symptoms, it is also characterized by neuropsychiatric comorbidities, such as anxiety and depression. Phosphodiesterase-5 inhibitors (PDE5Is) such as Sildenafil and Tadalafil have been shown to possess antidepressant-like effects, but the mechanisms underpinning such effects are not fully characterized. To address this question, we used the EAE model of MS, behavioral tests, immunofluorescence, immunohistochemistry, western blot, and 16 S rRNA sequencing. Here, we showed that depressive-like behavior in Experimental Autoimmune Encephalomyelitis (EAE) mice is due to neuroinflammation, reduced synaptic plasticity, dysfunction in glutamatergic neurotransmission, glucocorticoid receptor (GR) resistance, increased blood-brain barrier (BBB) permeability, and immune cell infiltration to the CNS, as well as inflammation, increased intestinal permeability, and immune cell infiltration in the distal colon. Furthermore, 16 S rRNA sequencing revealed that behavioral dysfunction in EAE mice is associated with changes in the gut microbiota, such as an increased abundance of Firmicutes and Saccharibacteria and a reduction in Proteobacteria, Parabacteroides, and Desulfovibrio. Moreover, we detected an increased abundance of Erysipelotrichaceae and Desulfovibrionaceae and a reduced abundance of Lactobacillus johnsonii. Surprisingly, we showed that Tadalafil likely exerts antidepressant-like effects by targeting all aforementioned disease aspects. In conclusion, our work demonstrated that anxiety- and depressive-like behavior in EAE is associated with a plethora of neuroimmune and gut microbiota-mediated mechanisms and that Tadalafil exerts antidepressant-like effects probably by targeting these mechanisms. Harnessing the knowledge of these mechanisms of action of Tadalafil is important to pave the way for future clinical trials with depressed patients.

Mechanisms involved in the antidepressant-like action of orally administered 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) in male and female mice.

RATIONALE: The compound 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) has recently been shown to inhibit in vitro acetylcholinesterase activity, reduce cognitive damage, and improve neuropsychic behavior in mice, making it a promising molecule to treat depression. OBJECTIVES: This study investigated the antidepressant-like action of MTDZ in mice and its potential mechanisms of action. RESULTS: Molecular docking assays were performed and suggested a potential inhibition of monoamine oxidase A (MAO-A) by MTDZ. The toxicity study revealed that MTDZ displayed no signs of toxicity, changes in oxidative parameters, or alterations to biochemistry markers, even at a high dose of 300 mg/kg. In behavioral tests, MTDZ administration reduced immobility behavior during the forced swim test (FST) without adjusting the climbing parameter, suggesting it has an antidepressant effect. The antidepressant-like action of MTDZ was negated with the administration of 5-HT1A, 5-HT1A/1B, and 5-HT3 receptor antagonists, implying the involvement of serotonergic pathways. Moreover, the antidepressant-like action of MTDZ was linked to the NO system, as L-arginine pretreatment inhibited its activity. The ex vivo assays indicated that MTDZ normalized ATPase activity, potentially linking this behavior to its antidepressant-like action. MTDZ treatment restricted MAO-A activity in the cerebral cortices and hippocampi of mice, proposing a selective inhibition of MAO-A associated with the antidepressant-like effect of the compound. CONCLUSIONS: These findings suggest that MTDZ may serve as a promising antidepressant agent due to its selective inhibition of MAO-A and the involvement of serotonergic and NO pathways.

Carvacrol alleviates CUMS-induced depressive-like behaviors and cognitive impairment by reducing oxidative stress and neuroinflammation in mice.

The present study aimed to evaluate the protective potential of carvacrol against depressive-like behavior and cognitive impairment prompted by chronic unpredictable mild stress (CUMS) in mice. The animals were divided into six groups: Control (non-stressed), CARV (carvacrol at 50 mg/kg, p.o.), FLU (fluoxetine at 10 mg/kg, p.o.), CUMS (stressed), CUMS + CARV and CUMS + FLU, and the groups with CUMS were subjected to different stressors for 28 days. After treatment, mice underwent behavioral testing (open field, forced swimming, sucrose preference, social interaction, novel object recognition and Y-maze) and brain areas were removed for oxidative stress (MDA, nitrite/nitrate and GSH levels) and cytokine (IL-1ß and TNF-α) content assays. The results revealed that CARV administration reversed depressive-like behavior and significantly ameliorated the cognitive deficit induced by CUMS, as well as was able to attenuate oxidative stress (decreased MDA and nitrite/nitrate levels and increased GSH levels). In addition, a significant reduction in hippocampal IL-1ß and TNF-α levels was observed, demonstrating a potential anti-neuroinflammatory activity. Taken together, the antioxidant and anti-inflammatory activities observed in this study indicate that CARV is a promising drug for antidepressant treatment.

Development and pharmacological evaluation of liposomes and nanocapsules containing paroxetine hydrochloride.

Depression is one of the most common psychiatric disorders. Nanotechnology has emerged to optimize the pharmacological response. Therefore, the aim of this work was to develop and characterize liposomes and nanocapsules containing paroxetine hydrochloride and evaluate their antidepressant-like effect using the open field and tail suspension tests in mice. Liposomes and nanocapsules were prepared using the reverse-phase evaporation and nanoprecipitation methods, respectively. The particle size of the formulation ranged from 121.81 to 310.73 nm, the polydispersity index from 0.096 to 0.303, the zeta potential from -11.94 to -34.50 mV, the pH from 5.31 to 7.38, the drug content from 80.82 to 94.36 %, and the association efficiency was 98 %. Paroxetine hydrochloride showed slower release when associated with liposomes (43.82 %) compared to nanocapsules (95.59 %) after 10 h. In Vero cells, in vitro toxicity showed a concentration-dependent effect for paroxetine hydrochloride nanostructures. Both nanostructures decreased the immobility time in the TST at 2.5 mg/kg without affecting the number of crossings in the open field test, suggesting the antidepressant-like effect of paroxetine. In addition, the nanocapsules decreased the number of groomings, reinforcing the anxiolytic effect of this drug. These results suggest that the nanostructures were effective in preserving the antidepressant-like effect of paroxetine hydrochloride even at low doses.

Rapid and long-lasting effects of subcutaneous esketamine on suicidality: An open-label study in patients with treatment-resistant depression.

Therapeutics for suicide management is limited, taking weeks to work. This open-label clinical trial with 18 treatment-resistant depressive patients tested subcutaneous esketamine (8 weekly sessions) for suicidality. We noted a rapid and enduring effect of subcutaneous esketamine, lasting from one week to six months post-treatment, assessed by the Beck Inventory for Suicidality (BSI). There was an immediate drop in suicidality, 24 h following the initial dose, which persisted for seven days throughout the eight-week dosing period. Additionally, this study is the first to examine a six-month follow-up after multiple administrations of subcutaneous esketamine, finding consistently lower levels of suicidality throughout this duration. Conversely, suicidality also was measured along the 8-weeks of treatment by a psychiatrist using the Montgomery-Asberg Depression Rating Scale (MADRS), which showed significant reduction only after two treatment sessions expanding until the last session. Moreover, notably, 61% of patients achieved remission on suicidality (MADRS). These results suggest that weekly subcutaneous esketamine injections offer a cost-effective approach that induces a rapid and sustained response to anti-suicide treatment. This sets the stage for further, more controlled studies to corroborate our initial observations regarding the effects of SC esketamine on suicidality. Registered trial at: https://ensaiosclinicos.gov.br/rg/RBR-1072m6nv.

Geografías de prescripción y consumo de antidepresivos en servicios de salud pública de Montevideo (Uruguay) / Geographies of prescription and consumption of antidepressants in public health services in Montevideo (Uruguay)

El uso de antidepresivos está ampliamente extendido a nivel mundial y junto con las benzodiacepinas son los psicofármacos más prescritos. Son utilizados en un amplio rango de condiciones clínicas, observándose un aumento en su prescripción y consumo a nivel internacional, regional y nacional. En ese sentido, el enfoque que considera el espacio geográfico como dimensión activa en dicha problemática es de incipiente desarrollo. En el presente estudio y a partir de un diseño mixto se analizaron las dimensiones sociotécnicas que generaron geografías de prescripción y consumo de antidepresivos en servicios de salud pública de Montevideo, en usuarios mayores de 14 años, entre marzo 2018 y marzo 2019. Se identificaron espacios de la ciudad con diferentes niveles de consumo y la emergencia del antidepresivo como objeto cultural aglutinante de múltiples situaciones sociosanitarias, siendo nexo entre grupos sociales diversos y distintivo en el reconocimiento de áreas de la ciudad, en tanto problemáticas socioeconómicas y padecimientos psíquicos.

The use of antidepressants is widely spread worldwide; they are the most prescribed psychotropic drugs, together with benzodiazepines. They are used in a wide range of clinical conditions, with an increase in their prescription and use at an international, regional and national level. In that sense, the consideration of geographic space as an active dimension in this problem is an incipient development. In the present study and based on a mixed design, an analysis is presented of the sociotechnical dimensions that generated geographies of prescription and use of antidepressants in public health services of Montevideo, in users over 14 years of age, between March 2018 and March 2019. Authors identify city areas with different levels of antidepressants use and describe its emergence as a cultural object that brings together multiple socio-health situations, becoming a link between diverse social groups and distinctive in the recognition of city areas, with specific socioeconomic problems and psychological sufferings.

Análisis del conocimiento sobre los inhibidores selectivos de la recaptura de serotonina (ISRS) en el manejo de la depresión por médicos residentes y concurrentes de clínica médica de 5 hospitales de CABA / Review of the Knowledge on Selective Serotonin Reuptake Inhibitors (SSRIs) for Depression Management by Resident and Intern Physicians of the Medical Clinic of 5 Hospitals in CABA

Introducción: la depresión es un trastorno cada vez más prevalente alrededor del mundo. Los médicos generales son los profesionales de la salud más consultados por pacientes deprimidos. Más del 70% de los pacientes con depresión son vistos por médicos generales y no por especialistas en Psiquiatría. Según estudios realizados en Buenos Aires, más del 25% de los pacientes internados en Servicios de Clínica Médica en hospitales generales presenta depresión. Estos pacientes suelen ser atendidos y seguidos por médicos en formación, sean residentes o concurrentes de Clínica Médica. El objetivo del trabajo fue analizar el conocimiento sobre los inhibidores selectivos de la recaptura de serotonina (ISRS) que tienen los médicos residentes y concurrentes de Clínica Médica de 5 hospitales de la Ciudad Autónoma de Buenos Aires (CABA) y describir el tratamiento de un paciente depresivo por ellos. Material y métodos: se realizó un estudio descriptivo de corte transversal con un muestreo de tipo no probabilístico. Se utilizó como instrumento de medición un cuestionario semiestructurado organizado en dos secciones, una de datos demográficos que permiten caracterizar la muestra. La otra, de 15 ítems, explora los conocimientos sobre los ISRS y el tratamiento de la depresión. Dicho cuestionario fue revisado por 4 expertos. El instrumento es anónimo. Se aplicó a 59 médicos en formación en Clínica Médica, residentes y concurrentes, de 5 hospitales de la CABA, que participaron de forma voluntaria, durante el período agosto-septiembre de 2022. Resultados: la mayoría de los médicos en formación en Clínica Médica no tratan cuadros depresivos y, ante un paciente deprimido, solicitan la evaluación por un especialista en Salud Mental. Solo un 6,8% lo medica con un antidepresivo. Más del 75% de la muestra refiere recordar los conocimientos que tiene sobre de los ISRS de la cursada de Farmacología y un 13,6 de la cursada de Psiquiatría en la Facultad de Medicina. Conclusión: se observa un conocimiento deficitario sobre los ISRS en médicos residentes y concurrentes de Clínica Médica. Se considera necesario reforzar la formación sobre depresión y manejo de antidepresivos durante la residencia/concurrencia de Clínica Médica. (AU)

Introduction: depression is an increasingly common disorder around the world. General practitioners are the most frequently consulted health professionals by depressed patients. More than 70% of all depressed patients receive treatment by general practitioners and not by psychiatric specialists. According to studies conducted in Buenos Aires, more than 25% of all patients admitted to the Clinical Services in public hospitals present depression. These patients are usually under the care and follow-up of clinical trainee physicians, residents, or interns.This study aimed to analyze the knowledge about selective serotonin reuptake inhibitors (SSRIs) of clinical trainee residents and interns in five hospitals in the Ciudad Autónoma de Buenos Aires (CABA) and to describe their treatment of a depressive patient. Material and methods: we conducted a descriptive cross-sectional study with a non-probabilistic sampling. We used a semi-structured questionnaire arranged into two sections as a measuring tool. One, with demographic data to describe the sample. The other, with 15 items, explores respondents' knowledge of SSRIs and the treatment of depression. Four experts reviewed the questionnaire, which was anonymous. We applied it to 59 clinical medical trainees, residents, and interns from five CABA hospitals who volunteered to participate during August-September 2022. Results: most clinical trainees do not treat depressive conditions and, when confronted with a depressed patient, request an assessment by a Mental Health specialist. Only 6.8% medicate the patient with an antidepressant. More than 75% of the sample reported remembering their knowledge of SSRIs from the Pharmacology course and 13.6% from the Psychiatry course at the School of Medicine. Conclusion: there is a deficient knowledge about SSRIs in trainee residents and interns of Clínica Médica. We believe it is necessary to reinforce training on depression and management of antidepressants during residency/internship practice in Clínica Médica. (AU)

Diretrizes clínicas para tratamento da depressão: análise de fatores associados à qualidade e comparação de recomendações para pacientes não respondedores e com depressão resistente / Clinical guidelines for the treatment of depression: analysis of factors associated with quality and comparison of recommendations for nonresponding patients and for patients with resistant depression

Diretrizes clínicas (DCs) de alta qualidade são importantes para a assistência efetiva de pacientes com doenças crônicas, incluindo a depressão. A depressão é um dos principais problemas de saúde mundial, sendo um dos transtornos psiquiátricos mais comumente encontrados na prática médica, afetando cerca de 300 milhões de pessoas. Além de sua natureza debilitante e onerosa, muitas vezes pode levar a desfechos graves, tal como o suicídio, principalmente em pacientes que não respondem aos tratamentos. Assim, o objetivo geral desta tese foi identificar fatores das DCs associados à qualidade metodológica desses documentos e de suas recomendações, e comparar as recomendações para duas situações de falhas da farmacoterapia: pacientes não respondedores e pacientes com depressão resistente ao tratamento (DRT). Operacionalmente, foram feitas revisões sistemáticas da literatura em bases científicas e específicas de DCs, e incluídas DCs publicadas nos últimos onze anos que contivessem recomendações para o tratamento farmacológico de adultos com depressão. Para avaliação geral das DCs, foi aplicado o instrumento AGREE II, e para avaliação específica das recomendações, o instrumento AGREE-REX. As DCs foram consideradas de alta qualidade quando pontuaram com escores maiores ou iguais a 60% (no estudo descrito no capítulo 2) e maiores ou iguais a 80% (no estudo descrito no capítulo 3) no domínio 3 (Rigor de desenvolvimento) do AGREE II. As DCs com recomendações de alta qualidade foram as que pontuaram com mais de 60% no domínio 1 (Aplicabilidade Clínica) do AGREE-REX. Das 63 DCs selecionadas, 17 (27%) apresentaram alta qualidade, e 7 (11%) apresentaram recomendações de alta qualidade. Os fatores associados à maior qualidade foram gerenciamento de conflitos de interesses, equipe multiprofissional e tipo de instituição. A inclusão de representante do paciente na equipe também foi associada a recomendações de maior qualidade. Verificou-se que a maioria das DCs concorda com a necessidade de: reavaliar o diagnóstico, a presença de comorbidades, a adesão ao tratamento, ajustar a dosagem do antidepressivo e adicionar psicoterapia como os primeiros passos para aqueles que não respondem ao tratamento antidepressivo de primeira linha. Em relação às recomendações, há falhas importantes, incluindo a não apresentação de definição padronizada de resposta adequada/inadequada/parcial, e o não estabelecimento de tempo de tratamento necessário para declarar DRT. Todas as DCs incluíram a possibilidade de substituição do antidepressivo, potencialização com outros medicamentos e combinação de antidepressivos. Todavia, três DCs não recomendaram uma sequência entre eles. Por fim, verificou-se que das 17 DCs de alta qualidade e das 7 DCs com recomendações de alta qualidade, apenas duas incluíram definição e recomendações para DRT. Não existe consenso entre as DCs de alta qualidade quanto à definição e uso do termo DRT. Não foi possível extrair uma estratégia terapêutica convergente para DRT em adultos. Os resultados obtidos reforçam a necessidade de maior foco no aprimoramento da qualidade das DCs e de suas recomendações, especialmente nos subgrupos relativos à resposta inadequada ao tratamento e a DRT, nas quais as definições não são claras

High-quality clinical practice guidelines (CPGs) are important for treating patients with chronic diseases such as depression. Depression is a major health concern worldwide, affecting approximately 300 million people. It is one of the most prevalent psychiatric disorders in medical practice. It is not only debilitating and costly but can also lead to tragic consequences such as suicide, particularly in patients who do not respond to treatment. The objective of this thesis was to identify CPGs factors associated with the methodological quality of these documents and their recommendations. Furthermore, this thesis aimed to compare the recommendations in two pharmacotherapy failure situations: inadequate response to treatment and treatment-resistant depression (TRD). Systematic literature reviews were conducted on scientific and CPG-specific databases. Reviews were also conducted on CPGs published in the last eleven years that included recommendations for pharmacological treatment of adults with depression. The AGREE II instrument was used for the CPGs general assessment, while the AGREE-REX instrument was used specifically to assess their recommendations. CPGs were considered high quality if they achieved a score of at least 60% in the study mentioned in Chapter 2 and a score of at least 80% in the study mentioned in Chapter 3 in the AGREE II, rigour of development domain. The CPGs with high-quality recommendations were those that scored greater than 60% in Domain 1 (Clinical Applicability) of the AGREE-REX. Of the 63 selected CPGs, 17 (27%) were high quality, and 7 (11.1%) had recommendations of high quality. Factors associated with higher quality were conflict of interest management, multi-professional team, and type of institution. Inclusion of a patients representative on the team was associated with higher quality recommendations. Most CPGs agreed with the need to reassess diagnoses, comorbidities, and treatment adherence. They also agreed on adjusting antidepressant dosage and providing psychotherapy as a first step for patients who do not respond to first-line antidepressant treatment. There are significant shortcomings in the recommendations. In particular, the lack of a standardized definition of adequate, inadequate, or partial response to treatment and the lack of clarity surrounding the duration of treatment required to establish TRD. All CPGs included the possibility of antidepressant substitution, potentiation with other drugs, and a combination of antidepressants. However, three CPGs did not recommend a preferred sequence for these interventions. Finally, of the 17 high-quality CPGs and the 7 CPGs with high-quality recommendations, only two included definition and recommendations for TRD. There is no consensus among the high-quality CPGs regarding the definition and use of the term TRD. Ultimately, finding a convergent therapeutic strategy for TRD in adults was not possible. These results highlighted the need to focus more on improving the quality of CPGs and their recommendations, especially in the subgroups related to inadequate response to treatment and TRD, where definitions are unclear

Use of ketamine and esketamine for depression: an overview of systematic reviews with meta-analyses.

PURPOSE: To summarize the evidence of efficacy and safety of the use of ketamine and esketamine for depression. METHODS: A literature search was performed in Medline, the Cochrane Library, LILACS, and CRD until November 2020. We included systematic reviews with meta-analyses of randomized controlled trials on the use of ketamine and esketamine in adult patients with depression. Two authors independently performed the study selection and data extraction. The AMSTAR-2 tool was used to appraise the quality of included reviews. RESULTS: A total of 118 records were identified, and 11 studies fully met the eligibility criteria. Compared to control, ketamine improved the clinical response at 40 min to 1 week and clinical remission at 80 min to 72 h, and esketamine improved both outcomes at 2 h to 4 weeks. Ketamine and esketamine also had a beneficial effect on the depression scales score and suicidality. For adverse events, oral ketamine did not show significant change compared to control, while intranasal esketamine showed difference for any events, such as dissociation, dizziness, hypoesthesia, and vertigo. Most reviews were classified as "critically low quality," and none of them declared the source of funding of the primary studies and assessed the potential impact of risk of bias in primary studies. CONCLUSION: Ketamine and esketamine showed a significant antidepressant action within a few hours or days after administration; however, the long-term efficacy and safety are lacking. In addition, the methodological quality of the reviews was usually critically low, which may indicate the need for higher quality evidence in relation to the theme.

Low Doses of Ketamine and Melatonin in Combination Produce Additive Antidepressant-like Effects in Mice.

Major depressive disorder is a disabling disease with the number of affected individuals increasing each year. Current antidepressant treatments take between three to six weeks to be effective with forty percent of patients being resistant to treatment, making it necessary to search for new antidepressant treatments. Ketamine, a phencyclidine hydrochloride derivative, given intravenously, induces a rapid antidepressant effect in humans. In mice, it causes increased neurogenesis and antidepressant-like effects. However, it also produces psychomimetic effects in humans and in rodents increases the locomotor activity. In contrast, melatonin, a hormone secreted by the pineal gland and synthesized in extrapineal sites, increases new neuron formation and causes antidepressant-like effects in adult rodents with no collateral effects. Here, we assessed the effects of a non-effective dose of ketamine in combination with melatonin (KET/MEL), both on neurogenesis as well as on the antidepressant-like effect in mice. Our results showed that KET/MEL combination increased neurogenesis and produced antidepressant-like effects without altering locomotor activity after both single and triple administration protocols. Our data strongly suggest that KET/MEL combination could be used to simultaneously promote neurogenesis, reverting neuronal atrophy and inducing antidepressant-like effects.

Behavioral and neurochemical effects of folic acid in a mouse model of depression induced by TNF-α.

Folic acid has been reported to exert antidepressant effects, but its ability to abrogate the depressive-like behavior and signaling pathways alterations elicited by an inflammatory model of depression remains to be established. This study examined: a) the efficacy of folic acid in a mouse model of depression induced by tumor necrosis factor (TNF-α); b) whether the administration of subthreshold doses of folic acid and antidepressants (fluoxetine, imipramine, and bupropion), MK-801, or 7-nitroindazole cause antidepressant-like effects; c) the effects of TNF-α and/or folic acid on hippocampal p38MAPK, Akt, ERK, and JNK phosphorylation. Folic acid reduced the immobility time in the tail suspension test (TST) in control mice (10-50 mg/kg, p.o) and abolished the depressive-like behavior elicited by TNF-α (0.001 fg/site, i.c.v.) in this test (1-50 mg/kg, p.o). Coadministration of subthreshold doses of folic acid (1 mg/kg, p.o.) and fluoxetine, imipramine, bupropion, MK-801, or 7-nitroindazole produced an antidepressant-like effect in mice exposed or not to TNF-α. TNF-α-treated mice presented increased p38MAPK phosphorylation and decreased Akt phosphorylation, and the later effect was prevented by folic acid (10 mg/kg, p.o.). Additionally, ERK1 phosphorylation was increased in mice treated with TNF-α + folic acid (1 mg/kg), but no effects on ERK2 or JNK1/2/3 phosphorylation were found in any group. The results indicate the efficacy of folic acid to counteract the depressive-like behavior induced by a pro-inflammatory cytokine, an effect that might be associated with the activation of monoaminergic systems, inhibition of N-methyl-d-aspartate (NMDA) receptors and nitric oxide (NO) synthesis, as well as Akt modulation.

Involvement of dopamine D2 and glutamate NMDA receptors in the antidepressant-like effect of amantadine in mice.

The present study investigated the pharmacological mechanisms of the antidepressant-like effects of amantadine in mice and their influence on hippocampal neurogenesis. To improve the translational validity of preclinical results, reproducibility across laboratories and replication in other animal models and species are crucial. Single amantadine administration at doses of 50 and 75 mg/kg resulted in antidepressant-like effects in mice in the tail suspension test (TST), reflected by an increase in immobility time. The effects of amantadine were seen at doses that did not alter locomotor activity. The tyrosine hydroxylase inhibitor α-methyl-ρ-tyrosine did not influence the anti-immobility effect of amantadine in the TST. Pretreatment with the α1 adrenergic receptor antagonist prazosin, ß adrenergic receptor antagonist propranolol, α2 adrenergic receptor antagonist yohimbine, and α2 adrenergic receptor agonist clonidine did not alter the antidepressant-like effect of amantadine. However, amantadine's effect was blocked by the dopamine D2 receptor antagonist haloperidol and glutamate receptor agonist N-methyl-D-aspartate (NMDA). Repeated amantadine administration (50 mg/kg) also exerted an antidepressant-like effect, paralleled by an increase in hippocampal neurogenesis. The present results demonstrate that the antidepressant-like effects of amantadine may be mediated by its actions on D2 and NMDA receptors and likely involve hippocampal neurogenesis.

Co-administration of cannabidiol and ketamine induces antidepressant-like effects devoid of hyperlocomotor side-effects.

BACKGROUND AND PURPOSE: Although useful as a rapid-acting antidepressant drug, ketamine is known to induce psychotomimetic effects, which may interfere with its therapeutic use. Cannabidiol (CBD) is a non-psychostimulant compound from Cannabis sativa, which has shown promising antidepressant effects without inducing hyperlocomotion. AMPA receptor activation is involved in the antidepressant effect induced by ketamine, but its relevance for the effects of CBD is not known. Moreover, given that CBD has antipsychotic and antidepressant properties, it is unknown whether adding CBD to ketamine could potentiate the antidepressant properties of ketamine while also attenuating its psychostimulant effects. EXPERIMENTAL APPROACH: S-Ketamine (2.5, 3, 5, 10, 30 mg/kg) and cannabidiol (3, 10, 30 mg/kg) were administered alone or in combination to male Swiss mice. Independent groups received NBQX (AMPA receptor antagonist) 5 min before administration of CBD or S-ketamine. The antidepressant-like effect was assessed in the forced swimming test (FST), and the open field test (OFT) evaluated the psychostimulant effect. KEY RESULTS: CBD induced significant dose-dependent antidepressant effects without causing hyperlocomotion in the OFT. S-ketamine produced an antidepressant effect associated with hyperlocomotion in the higher dose. NBQX inhibited the antidepressant effect of both ketamine and CBD. Pretreatment with CBD (10 mg/kg) attenuated the ketamine-induced hyperlocomotion while preserving its antidepressant effect. CONCLUSION: AND IMPLICATIONS: Similar to ketamine, the antidepressant-like effect elicited by CBD involves AMPA receptor activation. Additionally, CBD prevents the hyperlocomotion induced by S-ketamine without affecting its antidepressant-like effect. Our findings suggest that CBD and ketamine's combined administration can be a promising therapeutic strategy for achieving an appropriate antidepressant effect without unwanted side-effects. This article is part of the special issue on 'Cannabinoids'.

Repeated subcutaneous esketamine for treatment-resistant depression: Impact of the degree of treatment resistance and anxiety comorbidity.

BACKGROUND: A large number of studies indicate that subanesthetic doses of ketamine induce a fast antidepressant effect. Limited studies have investigated the subcutaneous (SC) route, and it remains unclear for whom this treatment is most suitable. AIMS: The aim of this study was to examine the effect on depressive symptoms of repeated subanesthetic doses of SC esketamine in unipolar and bipolar treatment-resistant depression (TRD) and clinical predictors of response. METHODS: A retrospective analysis of 70 patients who received six SC esketamine doses weekly as an adjunctive treatment was carried out. Doses started at 0.5 mg/kg and it could be titrated up to 1 mg/kg, according to response. The primary outcome was reduction in depressive symptoms. Statistical analysis to investigate clinical predictors of effectiveness included logistic regression analysis using a dependent variable of a 50% reduction in rating scale scores at the end of treatment. Comparisons between groups were made through analysis of variance and treatment effects. RESULTS: At baseline, our sample presented with severe treatment resistance in 65.7%, as assessed by the Maudsley Staging Method (MSM), and 47.1% had anxiety disorder comorbidity. The response rate was 50%. A better outcome was predicted by mild and moderate MSM scores (OR = 3.162, p = 0.041) and anxiety disorder comorbidity (OR = 3.149, p = 0.028). CONCLUSIONS: Our results suggest that higher levels of treatment resistance may be associated with a poor response to SC esketamine. Unlike traditional pharmacotherapies, it might benefit those with poor prognosis such as patients with depression and comorbid anxiety. Therefore, future research could investigate whether esketamine should receive a more prominent place in the treatment algorithm for TRD.

Ketamine treatment protects against oxidative damage and the immunological response induced by electroconvulsive therapy.

BACKGROUND: Electroconvulsive therapy (ECT) is often recommended for major depressive disorder (MDD) for those who do not respond to the first and second antidepressant trials. A combination of two therapies could improve antidepressant efficacy. Thus, this study aimed to investigate the synergistic effects of ECT combined to antidepressants with a different mechanism of action. METHODS: Rats were treated once a day, for five days with ketamine (5 mg/kg), fluoxetine (1 mg/kg), and bupropion (4 mg/kg) alone or in combination with ECT (1 mA; 100 V). After, oxidative damage and antioxidant capacity were assessed in the prefrontal cortex (PFC) and hippocampus, and pro-inflammatory cytokines levels were evaluated in the serum. RESULTS: ECT alone increased lipid peroxidation in the PFC and hippocampus. In the PFC of rats treated with ECT in combination with fluoxetine and bupropion, and in the hippocampus of rats treated with ECT combined with ketamine and bupropion there was a reduction in the lipid peroxidation. The nitrite/nitrate was increased by ECT alone but reverted by combination with ketamine in the hippocampus. Superoxide dismutase (SOD) was increased by ECT and maintained by fluoxetine and bupropion in the PFC. ECT alone increased interleukin-1ß (IL-1ß) and the administration of ketamine was able to revert this increase showing a neuroprotective effect of this drug when in combination with ECT. CONCLUSION: The treatment with ECT leads to an increase in oxidative damage and alters the immunological system. The combination with ketamine was able to protect against oxidative damage and the immunological response induced by ECT.

Intravenous arketamine for treatment-resistant depression: open-label pilot study.

We aimed to analyze the efficacy and safety of arketamine, the R(-)-enantiomer of ketamine, for treatment-resistant depression (TRD) in humans. Open-label pilot trial, seven subjects with TRD received a single intravenous infusion of arketamine (0.5 mg/kg); primary outcome was change in Montgomery-Åsberg Depression Rating Scale (MADRS) 24 h after. Mean MADRS dropped from 30.7 before infusion to 10.4 after one day, a mean difference of 20.3 points [CI 95% 13.6-27.0; p < 0.001]; dissociation was nearly absent. Arketamine might produce fast-onset and sustained antidepressant effects in humans with favorable safety profile, like previously reported with animals; further controlled-trials are needed.

Calea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects, and increases the hippocampal activity during REM sleep in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Calea zacatechichi is a plant with an extensive popular and ritual use in Mexico. In healthy volunteers, it induces well-being and tranquility senses, and facilitates superficial stages of sleep. However, anxiolytic, and antidepressant-like effects and changes on the sleep-waking stages have not been explored. AIM: To determine anxiolytic and antidepressant-like effects of an aqueous extract of C. zacatechichi (CZ) in rodents and to analyze their effects on hippocampal activity in the rat sleep-waking cycle. MATERIAL AND METHODS: CZ anxiolytic- and antidepressant-like effects were evaluated in several mice and rat behavioral paradigms. CZ effects on temporal distribution of sleep were described, and hippocampus EEG frequency patterns were analyzed during the sleep-waking cycle; absolute and relative powers were analyzed during Rapid Eye Movements (REM) and non-REM sleep stages. CZ chemical analysis was performed by UPLC-ESI-MS. RESULTS: CZ produced specific and robust anxiolytic- and antidepressant-like effects in mice and rats, similar to those of prototypical drugs, at doses ranging from 0.5 to 50 mg/kg. CZ at 100 mg/kg produced visible mild sedative effects in rats, associated with a significant increase in Slow Wave Sleep episodes during a 6 h recording, and enhanced fast frequencies of hippocampus (gamma-band:31-50 Hz) during REM sleep. CONCLUSION: Results could support the well-being and tranquility senses reported by healthy consumers, and to explain the oneiric content during dreams and some improvements in cognitive processes described by consumers. Anxiolytic- and antidepressant-like effects of this species, reported for first time in this study could improve some aspects of mental health.

Potential antidepressant-like effect of piperazine derivative LQFM212 in mice: Role of monoaminergic pathway and brain-derived neurotrophic factor.

Major depression disorder (MDD) is one of the most widespread and debilitating psychiatric diseases and may be associated with other mental disorders such as anxiety. Despite advances in neurobiology studies, currently no established mechanism can explain all facets of MDD, and available drugs often show therapeutic delay for clinical effectiveness and response rates in patients are around 50 %. Previous activities of piperazine derivatives on CNS are indicators of its therapeutic potential for treating mental disorders. In this regard, we have previously shown that the piperazine derivative 2,6-di-tert-butyl-4-((4-(2-hydroxyethyl)piperazin-1-yl)methyl)phenol (LQFM212) has anxiolytic-like activity which involves serotonergic pathway, nicotinic receptors and BZD-site of GABAA receptor, without cognitive impairments. Herein, was evaluated the potential antidepressant-like effect of LQFM212 on forced swimming test (FST) after a single dose of 54 µmol/kg and after repeated treatment for 15 days in mice. Pretreatment with WAY-100635, PCPA, prazosin, SCH-23390, sulpiride or AMPT reversed the antidepressant-like effect on FST, suggesting that monoaminergic pathway contributes for effects of LQFM212. Furthermore, repeated treatment with LQFM212 increased hippocampal BDNF levels dosed by ELISA kit. In assessment of possible adverse effects, repeated treatment with LQFM212 did not alter the body weight of the animals, glutathione levels in the liver, and serum levels of AST, ALT, urea, and creatinine. Taken together, the results showed that LQFM212 has an antidepressant-like effect that involves monoaminergic pathway and increased BDNF levels. This compound represents promising candidate for prototype of psychoactive drugs for treatment of anxiety and depression disorders since these pathological conditions may exist in comorbidities.

Adaptogenic effects of curcumin on depression induced by moderate and unpredictable chronic stress in mice.

Curcumin has been investigated for the prevention and treatment of diseases due to its anti-oxidant, anti-inflammatory, immunomodulatory, and neuroprotective actions. This current study evaluated the adaptogenic effects of a subchronic oral administration of curcumin to Swiss mice that were submitted to a chronic unpredictable mild stress (CUMS) model of depression. Four groups of mice (vehicle control, CO; curcumin control, COC; CUMS + vehicle, CUMS; CUMS + curcumin, CUMSC) were evaluated for the biochemical parameters. The CUMS model caused depressive-like and anxiety-like behavior in the animals when they were viewed in the Forced Swimming Test and in the Elevated Plus Maze Test. The treatments with curcumin prevented the depressive-like behavior in the Forced Swimming Test and they had anxiolytic effects on the non-stressed animals. This was confirmed by the Elevated Plus Maze Test. Curcumin showed antioxidant effects (IC50 of 38.86 ± 1.78 µg/mL) in the in vitro DPPH (2,2-diphenyl-1-picryl-hydrozole) test. The compound also showed antioxidant effects in vivo, increasing the catalase (CAT) levels in the brains of the stressed animals. The biochemical analyses did not reveal potential renal and hepatic damage. Together, these results have demonstrated the antidepressant and antioxidant effects of curcumin, highlighting in this mice model, the compound's novel adaptogenic potential.