Activation of ATP-sensitive potassium channel by iptakalim normalizes stress-induced HPA axis disorder and depressive behaviour by alleviating inflammation and oxidative stress in mouse hypothalamus

Natural products target pyroptosis for ameliorating neuroinflammation: A novel antidepressant strategy

BACKGROUND

Depression is a common mental disorder characterized by prolonged loss of interest and low mood, accompanied by symptoms such as sleep disturbances and cognitive impairments. In severe cases, there may be a tendency toward suicide. Depression can be caused by a series of highly complex pathological mechanisms; However, its key pathogenic mechanism remains unclear. As a novel programmed cell death (PCD) pathway and inflammatory cell death mode, pyroptosis involves a series of tightly regulated gene expression events. It may play a significant role in the pathogenesis and management of depression by modulating neuroinflammatory processes. In addition, a large number of studies have shown that various pharmacologically active natural products can regulate pyroptosis through multiple targets and pathways, demonstrating significant potential in the treatment of depression. These natural products offer advantages such as low costs and minimal side effects, making them a viable supplement or alternative to traditional antidepressants. In this review, we summarized recent research on natural products that regulate pyroptosis and neuroinflammation to improve depression. The aim of this review was to contribute to a scientific basis for the discovery and development of more natural antidepressants in the future.

METHODS

To review the antidepressant effects of natural products targeting pyroptosis-mediated neuroinflammation, data were collected from the Web of Science, ScienceDirect databases, and PubMed to classify and summarize the relationship between pyroptosis and neuroinflammation in depression, as well as the pharmacological mechanisms of natural products.

RESULTS

Multiple researches have revealed that pyroptosis-mediated neuroinflammation serves as a pivotal contributory factor in the pathological process of depression. Natural products, such as terpenoids, terpenes, phenylethanol glycosides, and alkaloids, have antidepressant effects by regulating pyroptosis to alleviate neuroinflammation.

CONCLUSION

We comprehensively reviewed the regulatory effects of natural products in depression-related pyroptosis pathways, providing a uniquely insightful perspective for the research, development, and application of natural antidepressants. However, future research should further explore the modulatory mechanisms of natural products in regulating pyroptosis, which is of great importance for the genration of effective antidepressants.

Cross-continental environmental and genome-wide association study on children and adolescent anxiety and depression

Anxiety and depression in children and adolescents warrant special attention as a public health concern given their devastating and long-term effects on development and mental health. Multiple factors, ranging from genetic vulnerabilities to environmental stressors, influence the risk for the disorders. This study aimed to understand how environmental factors and genomics affect children and adolescents anxiety and depression across three cohorts: Adolescent Brain and Cognitive Development Study (US, age of 9-10; N=11,875), Consortium on Vulnerability to Externalizing Disorders and Addictions (INDIA, age of 6-17; N=4,326) and IMAGEN (EUROPE, age of 14; N=1888). We performed data harmonization and identified the environmental impact on anxiety/depression using a linear mixed-effect model, recursive feature elimination regression, and the LASSO regression model. Subsequently, genome-wide association analyses with consideration of significant environmental factors were performed for all three cohorts by mega-analysis and meta-analysis, followed by functional annotations. The results showed that multiple environmental factors contributed to the risk of anxiety and depression during development, where early life stress and school support index had the most significant and consistent impact across all three cohorts. In both meta, and mega-analysis, SNP rs79878474 in chr11p15 emerged as a particularly promising candidate associated with anxiety and depression, despite not reaching genomic significance. Gene set analysis on the common genes mapped from top promising SNPs of both meta and mega analyses found significant enrichment in regions of chr11p15 and chr3q26, in the function of potassium channels and insulin secretion, in particular Kv3, Kir-6.2, SUR potassium channels encoded by the KCNC1, KCNJ11, and ABCCC8 genes respectively, in chr11p15. Tissue enrichment analysis showed significant enrichment in the small intestine, and a trend of enrichment in the cerebellum. Our findings provide evidences of consistent environmental impact from early life stress and school support index on anxiety and depression during development and also highlight the genetic association between mutations in potassium channels, which support the stress-depression connection via hypothalamic-pituitary-adrenal axis, along with the potential modulating role of potassium channels.

The neurobiological mechanisms and therapeutic prospect of extracellular ATP in depression

BACKGROUND

Depression is a prevalent psychiatric disorder with high long-term morbidities, recurrences, and mortalities. Despite extensive research efforts spanning decades, the cellular and molecular mechanisms of depression remain largely unknown. What's more, about one third of patients do not have effective anti-depressant therapies, so there is an urgent need to uncover more mechanisms to guide the development of novel therapeutic strategies. Adenosine triphosphate (ATP) plays an important role in maintaining ion gradients essential for neuronal activities, as well as in the transport and release of neurotransmitters. Additionally, ATP could also participate in signaling pathways following the activation of postsynaptic receptors. By searching the website PubMed for articles about "ATP and depression" especially focusing on the role of extracellular ATP (eATP) in depression in the last 5 years, we found that numerous studies have implied that the insufficient ATP release from astrocytes could lead to depression and exogenous supply of eATP or endogenously stimulating the release of ATP from astrocytes could alleviate depression, highlighting the potential therapeutic role of eATP in alleviating depression.

AIM

Currently, there are few reviews discussing the relationship between eATP and depression. Therefore, the aim of our review is to conclude the role of eATP in depression, especially focusing on the evidence and mechanisms of eATP in alleviating depression.

CONCLUSION

We will provide insights into the prospects of leveraging eATP as a novel avenue for the treatment of depression.

NLRP3 inflammatory pathway. Can we unlock depression?

Depression holds the title of the largest contributor to worldwide disability, with the numbers expected to continue growing. Currently, there are neither reliable biomarkers for the diagnosis of the disease nor are the current medications sufficient for a lasting response in nearly half of patients. In this comprehensive review, we analyze the previously established pathophysiological models of the disease and how the interplay between NLRP3 inflammasome activation and depression might offer a unifying perspective. Adopting this inflammatory theory, we explain how NLRP3 inflammasome activation emerges as a pivotal contributor to depressive inflammation, substantiated by compelling evidence from both human studies and animal models. This inflammation is found in the central nervous system (CNS) neurons, astrocytes, and microglial cells. Remarkably, dysregulation of the NLRP3 inflammasome extends beyond the CNS boundaries and permeates into the enteric and peripheral immune systems, thereby altering the microbiota-gut-brain axis. The integrity of the brain blood barrier (BBB) and intestinal epithelial barrier (IEB) is also compromised by this inflammation. By emphasizing the central role of NLRP3 inflammasome activation in depression and its far-reaching implications, we go over each area with potential modulating mechanisms within the inflammasome pathway in hopes of finding new targets for more effective management of this debilitating condition.

Unleashing the Potential of Nrf2: A Novel Therapeutic Target for Pulmonary Vascular Remodeling

Pulmonary vascular remodeling, characterized by the thickening of all three layers of the blood vessel wall, plays a central role in the pathogenesis of pulmonary hypertension (PH). Despite the approval of several drugs for PH treatment, their long-term therapeutic effect remains unsatisfactory, as they mainly focus on vasodilation rather than addressing vascular remodeling. Therefore, there is an urgent need for novel therapeutic targets in the treatment of PH. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a vital transcription factor that regulates endogenous antioxidant defense and emerges as a novel regulator of pulmonary vascular remodeling. Growing evidence has suggested an involvement of Nrf2 and its downstream transcriptional target in the process of pulmonary vascular remodeling. Pharmacologically targeting Nrf2 has demonstrated beneficial effects in various diseases, and several Nrf2 inducers are currently undergoing clinical trials. However, the exact potential and mechanism of Nrf2 as a therapeutic target in PH remain unknown. Thus, this review article aims to comprehensively explore the role and mechanism of Nrf2 in pulmonary vascular remodeling associated with PH. Additionally, we provide a summary of Nrf2 inducers that have shown therapeutic potential in addressing the underlying vascular remodeling processes in PH. Although Nrf2-related therapies hold great promise, further research is necessary before their clinical implementation can be fully realized.

The Nrf2 Pathway in Depressive Disorders: A Systematic Review of Animal and Human Studies

There is increasing interest in the involvement of antioxidative systems in protecting from depression. Among these, Nrf2 occupies a central place. We aimed to review the role of Nrf2 in depression. For this reason, we conducted a PubMed search using as search strategy (psychiatr*[ti] OR schizo*[ti] OR psychot*[ti] OR psychos*[ti] OR depress*[ti] OR MDD[ti] OR BD[ti] OR bipolar[ti] OR Anxiety[ti] OR antidepress*[ti] OR panic[ti] OR obsess*[ti] OR compulsio*[ti] OR “mood disord*”[ti] OR phobi*[ti] OR agoraphob*[ti] OR anorex*[ti] OR anorect*[ti] OR bulimi*[ti] OR “eating disorder*”[ti] OR neurodevelopm*[ti] OR retardation[ti] OR autism[ti] OR autistic[ti] OR ASM[ti] OR adhd[ti] OR “attention-deficit”[ti]) AND nrf2, which on the 9th of March produced 208 results of which 89 were eligible for our purposes. Eligible articles were studies reporting data of Nrf2 manipulations or content by any treatment in human patients or animals with any animal model of depression. Most studies were on mice only (N = 58), 20 on rats only, and three on both rats and mice. There were two studies on cell lines (in vitro) and one each on nematodes and fish. Only four studies were conducted in humans, one of which was post mortem. Most studies were conducted on male animals; however, human studies were carried out on both men and women. The results indicate that Nrf2 is lower in depression and that antidepressant methods (drugs or other methods) increase it. Antioxidant systems and plasticity-promoting molecules, such as those in the Nrf2–HO-1, BDNF–TrkB, and cyclic AMP–CREB pathways, could protect from depression, while glycogen synthase kinase-3β and nuclear factor κB oppose these actions, thus increasing depressive-like behaviours. Since Nrf2 is also endowed with tumorigenic and atherogenic potential, the balance between benefits and harms must be taken into account in designing novel drugs aiming at increasing the intracellular content of Nrf2.

Microglia in depression: an overview of microglia in the pathogenesis and treatment of depression

Major depressive disorder is a highly debilitating psychiatric disorder involving the dysfunction of different cell types in the brain. Microglia are the predominant resident immune cells in the brain and exhibit a critical role in depression. Recent studies have suggested that depression can be regarded as a microglial disease. Microglia regulate inflammation, synaptic plasticity, and the formation of neural networks, all of which affect depression. In this review, we highlighted the role of microglia in the pathology of depression. First, we described microglial activation in animal models and clinically depressed patients. Second, we emphasized the possible mechanisms by which microglia recognize depression-associated stress and regulate conditions. Third, we described how antidepressants (clinical medicines and natural products) affect microglial activation. Thus, this review aimed to objectively analyze the role of microglia in depression and focus on potential antidepressants. These data suggested that regulation of microglial actions might be a novel therapeutic strategy to counteract the adverse effects of devastating mental disorders.

The combination of living Bifidobacterium, Lactobacillus, and Streptococcus improves social ranking and relieves anxiety-like behaviors in competitive mice in a social dominance tube test

INTRODUCTION

Social rank has a profound influence on the behavior and health of humans and animals.

METHODS

To explore the effect of a combination of living Bifidobacterium, Lactobacillus and Streptococcus (CLB) on anxiety- and depression-like behaviors and social rank, mice were subjected to a social dominance tube test (SDTT). The behaviors, rank, gut microbiota, and expression of inflammatory cytokines and brain-derived neurotrophic factor (BDNF) in the hippocampus were measured.

RESULTS

The results indicated that CLB improved the SDTT ranking score of the losers and alleviated anxiety-like behaviors of the winners. CLB decreased the level of Desulfovibrio and augmented the level of Mollicutes in the feces, increased BDNF content, and reduced the level of tumor necrosis factor-α in the hippocampus.

CONCLUSION

These findings indicated that CLB may be used for the treatment of anxiety and improvement of the rank score via regulation of gut microbiota and anti-inflammatory effects.

Antidepressant effect of catalpol on corticosterone-induced depressive-like behavior involves the inhibition of HPA axis hyperactivity, central inflammation and oxidative damage probably via dual regulation of NF-κB and Nrf2

This study aimed to investigate the antidepressant effect and mechanism of catalpol on corticosterone (CORT)-induced depressive-like behavior in mice for the first time. As a result, CORT injection induced depressive-like behaviors of mice in behavioral tests, aggravated the serum CORT, adrenocorticotropic hormone, and corticotropin-releasing hormone levels, and conspicuously elevated the phosphorylations of nuclear factor kappa-B (NF-κB) in the hippocampus and frontal cortex, and down-regulated the expression levels of nuclear factor erythroid-2-related factor 2 (Nrf2). Furthermore, CORT exposure dramatically augmented the levels of inflammatory factors (interleukin-1β, tumor necrosis factor-α, nitric oxide synthase, and nitric oxide) and lipid peroxidation product malondialdehyde, and attenuated the levels of antioxidants including reduced glutathione, glutathione S-transferase, total superoxide dismutase, and heme oxygenase-1 in the mouse hippocampus and frontal cortex. On the contrary, catalpol administration markedly suppressed the abnormalities of the above indicators. From the overall results, this study displayed that catalpol exerted a beneficial effect on CORT-induced depressive-like behavior in mice possibly via the inhibition of hypothalamus-pituitary-adrenal (HPA) axis hyperactivity, central inflammation and oxidative damage at least partially through dual regulation of NF-κB and Nrf2.

Iptakalim alleviates synaptic damages via targeting mitochondrial ATP-sensitive potassium channel in depression

Synaptic plasticity damages play a crucial role in the onset and development of depression, especially in the hippocampus, which is more susceptible to stress and the most frequently studied brain region in depression. And, mitochondria have a major function in executing the complex processes of neurotransmission and plasticity. We have previously demonstrated that Iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could improve the depressive-like behavior in mice. But the underlying mechanisms are not well understood. The present study demonstrated that Ipt reversed depressive-like phenotype in vivo (chronic mild stress-induced mice model of depression) and in vitro (corticosterone-induced cellular model). Further study showed that Ipt could upregulate the synaptic-related proteins postsynaptic density 95 (PSD 95) and synaptophysin (SYN), and alleviated the synaptic structure damage. Moreover, Ipt could reverse the abnormal mitochondrial fission and fusion, as well as the reduced mitochondrial ATP production and collapse of mitochondrial membrane potential in depressive models. Knocking down the mitochondrial ATP-sensitive potassium (Mito-KATP) channel subunit MitoK partly blocked the above effects of Ipt. Therefore, our results reveal that Ipt can alleviate the abnormal mitochondrial dynamics and function depending on MitoK, contributing to improve synaptic plasticity and exert antidepressive effects. These findings provide a candidate compound and a novel target for antidepressive therapy.

Crocetin ameliorates chronic restraint stress-induced depression-like behaviors in mice by regulating MEK/ERK pathways and gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

This study aimed at determining the effects of saffron on depression as well as its neuroprotective and pharmacological effects on the intestinal function of crocetin in mice exposed to chronic restraint stress.

MATERIALS AND METHODS

Chronic stress was induced in two-week-old ICR mice by immobilizing them for 6 h per day for 28 days. The mice were orally administered with crocetin (20, 40, 80 mg/kg), fluoxetine (20 mg/kg) or distilled water. The treatments were administered daily and open field and tail suspension tests were performed. Immunofluorescent and Western-bolt (WB) assays were conducted to determine the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1), the precursor of brain-derived neurotrophic factor (proBDNF), extracellular signal-regulated kinase 1/2 (ERK1/2), phosphorylated cAMP response element-binding (CREB) protein in the hippocampus. Serum levels of dopamine (DA), proBDNF, MKP-1 and CREB were measured by Elisa kits. High-throughput sequencing was carried out to analyze the composition of intestinal microbiota.

RESULTS

Crocetin ameliorated depressive-like behaviors caused by chronic restraint stress-induced depressive mice. It significantly attenuated the elevated levels of MKP-1, proBDNF, alanine transaminase, aspartate transaminase and increased the serum levels of DA as well as CREB. Histopathological analysis showed that crocetin suppressed hippocampus injury in restraint stress mice by protecting neuronal cells. Immunofluorescent and WB analysis showed elevated expression levels of ERK1/2, CREB and inhibited expression levels of MKP-1, proBDNF in the hippocampus. The intestinal ecosystem of the crocetin group partially recovered and was close to the control group.

CONCLUSIONS

Crocetin has neuroprotective properties and ameliorates the effects of stress-associated brain damage by regulating the MKP-1-ERK1/2-CREB signaling and intestinal ecosystem.

Targeting Nrf2-Mediated Oxidative Stress Response Signaling Pathways as New Therapeutic Strategy for Pituitary Adenomas

Oxidative stress and oxidative damage are the common pathophysiological characteristics in pituitary adenomas (PAs), which have been confirmed with many omics studies in PA tissues and cell/animal experimental studies. Nuclear factor erythroid 2 p45-related factor 2 (Nrf2), the core of oxidative stress response, is an oxidative stress sensor. Nrf2 is synthesized and regulated by multiple factors, including Keap1, ERK1/2, ERK5, JNK1/2, p38 MAPK, PKC, PI3K/AKT, and ER stress, in the cytoplasm. Under the oxidative stress status, Nrf2 quickly translocates from cytoplasm into the nucleus and binds to antioxidant response element /electrophile responsive element to initiate the expressions of antioxidant genes, phases I and II metabolizing enzymes, phase III detoxifying genes, chaperone/stress response genes, and ubiquitination/proteasomal degradation proteins. Many Nrf2 or Keap1 inhibitors have been reported as potential anticancer agents for different cancers. However, Nrf2 inhibitors have not been studied as potential anticancer agents for PAs. We recommend the emphasis on in-depth studies of Nrf2 signaling and potential therapeutic agents targeting Nrf2 signaling pathways as new therapeutic strategies for PAs. Also, the use of Nrf2 inhibitors targeting Nrf2 signaling in combination with ERK inhibitors plus p38 activators or JNK activators targeting MAPK signaling pathways, or drugs targeting mitochondrial dysfunction pathway might produce better anti-tumor effects on PAs. This perspective article reviews the advances in oxidative stress and Nrf2-mediated oxidative stress response signaling pathways in pituitary tumorigenesis, and the potential of targeting Nrf2 signaling pathways as a new therapeutic strategy for PAs.

Effects of different drying methods on the chemical constituents of Lilium lancifolium Thunb. based on UHPLC-MS analysis and antidepressant activity of the main chemical component regaloside A

The Lilium lancifolium Thunb. is a herb with multiple functions in both medicine and food in China, and its extracts have shown antidepressant effects. In this study, fresh bulbs of Lilium lancifolium Thunb. were processed to study the effects of different drying processes on changes in its main chemical components. We found that different drying methods can affect the chemical constituents of the herb. Among these components, Regaloside A has been found as the characteristic component. Here, Cell Counting Kit-8 assay, and Western blotting were used to evaluate the neuroprotective antidepressant effects of Regaloside A. The results showed the cell survival rate was improved, the phosphorylation levels of brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphatidylinositol 3 kinase, protein kinase B, and mammalian target of rapamycin were increased after Regaloside A treatment. In general, different drying methods have a significant influence on the chemical composition of the herb, and Regaloside A may be the main chemical component of the herb. It can alleviate the damage of corticosterone in SH-SY5Y cells, and phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin signaling mediated by brain-derived neurotrophic factor/tyrosine kinase receptor B may play an important role in the neuroprotective antidepressant effects of Regaloside A.

Oxidative Stress at the Crossroads of Aging, Stroke and Depression

Epidemiologic studies have shown that in the aging society, a person dies from stroke every 3 minutes and 42 seconds, and vast numbers of people experience depression around the globe. The high prevalence and disability rates of stroke and depression introduce enormous challenges to public health. Accumulating evidence reveals that stroke is tightly associated with depression, and both diseases are linked to oxidative stress (OS). This review summarizes the mechanisms of OS and OS-mediated pathological processes, such as inflammation, apoptosis, and the microbial-gut-brain axis in stroke and depression. Pathological changes can lead to neuronal cell death, neurological deficits, and brain injury through DNA damage and the oxidation of lipids and proteins, which exacerbate the development of these two disorders. Additionally, aging accelerates the progression of stroke and depression by overactive OS and reduced antioxidant defenses. This review also discusses the efficacy and safety of several antioxidants and antidepressants in stroke and depression. Herein, we propose a crosstalk between OS, aging, stroke, and depression, and provide potential therapeutic strategies for the treatment of stroke and depression.

Antidepressant Activity of Euparin: Involvement of Monoaminergic Neurotransmitters and SAT1/NMDAR2B/BDNF Signal Pathway

Depression is the most significant risk factor for suicide, yet the causes are complex and disease mechanism remains unclear. The incidence and disability rate of depression are very high and the efficacy of some traditional antidepressants is not completely satisfactory. Recently, some studies have found that benzofurans have anti-oxidation and anti-monoamine oxidase properties, which are related to depression. Euparin is a monomer compound of benzofuran, previous work by our team found that it improves the behavior of depressed mice. However, additional antidepressant effects and mechanisms of Euparin have not been reported. In this study, the Chronic Unpredictable Mild Stress (CUMS) model of mice was used to further investigate the effect and mechanism of Euparin on depression. Results showed that Euparin (8, 16 and 32 mg/kg) reduced depression-like behavior in mice compared with the model group. Meanwhile, all doses of Euparin were found to increase the contents of monoamine neurotransmitter and decrease monoamine oxidase and reactive oxygen species (ROS) levels in brain of depression mice. Additionally, Euparin restored CUMS-induced decrease of Spermidine/Spermine N1-Acetyltransferase 1 (SAT1), N-methyl-D-aspartate receptor subtype 2B (NMDAR2B) and brain derived neurotrophic factor (BDNF) expression. These findings demonstrate that Euparin has antidepressant properties, and its mechanism involves the SAT1/NMDAR2B/BDNF signaling pathway.

Purinergic Signaling and Related Biomarkers in Depression

It is established that purinergic signaling can shape a wide range of physiological functions, including neurotransmission and neuromodulation. The purinergic system may play a role in the pathophysiology of mood disorders, influencing neurotransmitter systems and hormonal pathways of the hypothalamic-pituitary-adrenal axis. Treatment with mood stabilizers and antidepressants can lead to changes in purinergic signaling. In this overview, we describe the biological background on the possible link between the purinergic system and depression, possibly involving changes in adenosine- and ATP-mediated signaling at P1 and P2 receptors, respectively. Furthermore, evidence on the possible antidepressive effects of non-selective adenosine antagonist caffeine and other purinergic modulators is reviewed. In particular, A2A and P2X7 receptors have been identified as potential targets for depression treatment. Preclinical studies highlight that both selective A2A and P2X7 antagonists may have antidepressant effects and potentiate responses to antidepressant treatments. Consistently, recent studies feature the possible role of the purinergic system peripheral metabolites as possible biomarkers of depression. In particular, variations of serum uric acid, as the end product of purinergic metabolism, have been found in depression. Although several open questions remain, the purinergic system represents a promising research area for insights into the molecular basis of depression.

Inhibition of phosphodiesterase 2 reverses gp91phox oxidase-mediated depression- and anxiety-like behavior

Phosphodiesterase 2 (PDE2) plays an important role in treatment of stress-related depression through regulation of antioxidant defense and neuroprotective mechanisms. However, the causal relationship between PDE2 and the prevalence of depression and anxiety upon exposure to oxidative stress has not been investigated. The present study examined whether the effects of PDE2 inhibition on oxidative stress were directly involved in reduced ROS by regulating NADPH subunits gp91phox oxidase. The results suggested that the PDE2 inhibitor Bay 60-7550 reversed oxidative stress-induced behavioral signature, i.e. depression and anxiety. Pretreatment with the oxidizing agent DTNB completely blocked, while the reducing agent DTT and the NADPH oxidase inhibitor apocynin potentiated the effects of Bay 60-7550 on behavioral abnormalities, demonstrating the relationship between PDE2 and oxidative stress. Consistently, an in vitro test revealed the positive correlation between ROS and PDE2 levels. Moreover, Bay 60-7550 decreased corticosterone-induced gp91phox expression, which is the source of ROS. The subsequent study suggested that Bay 60-7550 induced decrease in ROS and increase in cAMP/cGMP, pVASP, pCREB, and the neurotrophic factor BDNF levels, which were completely blocked by CRISPR/Cas9-mediated gp91phox overexpression and potentiated by gp91phox siRNA-based antioxidant strategies. The in vivo test in stressed mice further suggested that gp91phox overexpression completely blocked the antidepressant- and anxiolytic-like effects of Bay 60-7550, while gp91phox knockdown enhanced such effects. These results provide solid evidence that the antidepressant- and anxiolytic-like effects of Bay 60-7550 against stress are causally related to down-regulation of gp91phox and activation of the cAMP/cGMP-pVASP-CREB-BDNF signaling pathway.

ATP-sensitive potassium-channel inhibitor glibenclamide attenuates HPA axis hyperactivity, depression- and anxiety-related symptoms in a rat model of Alzheimer's disease

Affective disorders including depression and anxiety are among the most prevalent behavioral abnormalities in patients with Alzheimer's disease (AD), which affect the quality of life and progression of the disease. Dysregulation of the hypothalamic-pituitary-adrenal-(HPA) axis has been reported in affective disorders and AD. Recent studies revealed that current antidepressant drugs are not completely effective for treating anxiety- and depression-related disorders in people with dementia. ATP-sensitive-potassium-(K_ATP) channels are well-known to be involved in AD pathophysiology, HPA axis function and the pathogenesis of depression and anxiety-related behaviors. Thus, targeting of K_ATP channel may be a potential therapeutic strategy in AD. Hence, we investigated the effects of intracerebroventricular injection of Aβ25-35 alone or in combination with glibenclamide, K_ATP channel inhibitor on depression- and anxiety-related behaviors as well as HPA axis response to stress in rats. To do this, non-Aβ25-35- and Aβ25-35-treated rats were orally treated with glibenclamide, then the behavioral consequences were assessed using sucrose preference, forced swim, light-dark box and plus maze tests. Stress-induced corticosterone levels following forced swim and plus maze tests were also evaluated as indicative of abnormal HPA-axis-function. Aβ25-35 induced HPA axis hyperreactivity and increased depression- and anxiety-related symptoms in rats. Our results showed that blockade of K_ATP channels with glibenclamide decreased depression- and anxiety-related behaviors by normalizing HPA axis activity in Aβ25-35-treated rats. This study provides additional evidence that Aβ administration can induce depression- and anxiety-like symptoms in rodents, and suggests that K_ATP channel inhibitors may be a plausible therapeutic strategy for treating affective disorders in AD patients.

Molecular Mechanisms Underlying the Anti-depressant Effects of Resveratrol: a Review

Major depression is a public health problem, affecting 121 million people worldwide. Patients suffering from depression present high rates of morbidity, causing profound economic and social impacts. Furthermore, patients with depression present cognitive impairments, which could influence on treatment adherence and long-term outcomes. The pathophysiology of major depression is not completely understood yet but involves reduced levels of monoamine neurotransmitters, bioenergetics, and redox disturbances, as well as inflammation and neuronal loss. Treatment with anti-depressants provides a complete remission of symptoms in approximately 50% of patients with major depression. However, these drugs may cause side effects, as sedation and weight gain. In this context, there is increasing interest in studies focusing on the anti-depressant effects of natural compounds found in the diet. Resveratrol is a polyphenolic phytoalexin (3,4',5-trihydroxystilbene; C₁₄H₁₂O₃; MW 228.247 g/mol) and has been found in peanuts, berries, grapes, and wine and induces anti-oxidant, anti-inflammatory, and anti-apoptotic effects in several mammalian cell types. Resveratrol also elicits anti-depressant effects, as observed in experimental models using animals. Therefore, resveratrol may be viewed as a potential anti-depressant agent, as well as may serve as a model of molecule to be modified aiming to ameliorate depressive symptoms in humans. In the present review, we describe and discuss the anti-depressant effects of resveratrol focusing on the mechanism of action of this phytoalexin in different experimental models.