Mouse Model Of Restraint Stress Research Articles

Restraint Stress-Induced Neutrophil Inflammation Contributes to Concurrent Gastrointestinal Injury in Mice.

Psychological stress increases risk of gastrointestinal tract diseases. However, the mechanism behind stress-induced gastrointestinal injury is not well understood. The objective of our study is to elucidate the putative mechanism of stress-induced gastrointestinal injury and develop an intervention strategy. To achieve this, we employed the restraint stress mouse model, a well-established method to study the pathophysiological changes associated with psychological stress in mice. By orally administering gut-nonabsorbable Evans blue dye and monitoring its plasma levels, we were able to track the progression of gastrointestinal injury in live mice. Additionally, flow cytometry was utilized to assess the viability, death, and inflammatory status of splenic leukocytes, providing insights into the stress-induced impact on the innate immune system associated with stress-induced gastrointestinal injury. Our findings reveal that neutrophils represent the primary innate immune leukocyte lineage responsible for stress-induced inflammation. Splenic neutrophils exhibited elevated expression levels of the pro-inflammatory cytokine IL-1, cellular reactive oxygen species, mitochondrial burden, and cell death following stress challenge compared to other innate immune cells such as macrophages, monocytes, and dendritic cells. Regulated cell death analysis indicated that NETosis is the predominant stress-induced cell death response among other analyzed regulated cell death pathways. NETosis culminates in the formation and release of neutrophil extracellular traps, which play a crucial role in modulating inflammation by binding to pathogens. Treatment with the NETosis inhibitor GSK484 rescued stress-induced neutrophil extracellular trap release and gastrointestinal injury, highlighting the involvement of neutrophil extracellular traps in stress-induced gastrointestinal inflammation. Our results suggest that neutrophil NETosis could serve as a promising drug target for managing psychological stress-induced gastrointestinal injuries.

Stress increases hepatic release of lipocalin 2 which contributes to anxiety-like behavior in mice.

Chronic stress induces anxiety disorders via both neural pathways and circulating factors. Although many studies have elucidated the neural circuits involved in stress-coping behaviors, the origin and regulatory mechanism of peripheral cytokines in behavioural regulation under stress conditions are not fully understood. Here, we identified a serum cytokine, lipocalin 2 (LCN2), that was upregulated in participants with anxiety disorders. Using a mouse model of chronic restraint stress (CRS), circulating LCN2 was found to be related to stress-induced anxiety-like behaviour via modulation of neural activity in the medial prefrontal cortex (mPFC). These results suggest that stress increases hepatic LCN2 via a neural pathway, leading to disrupted cortical functions and behaviour.

A soy protein enzymatic digest mitigates Nrf2-related oxidative stress and attenuates depression-like behavior in a mouse model of sub-chronic restraint stress

Continuous oxidative stress conditions have been identified as a major cause of various neuropsychiatric disorders, including depression. The present study investigated the potential antidepressant-like effects of a soy protein enzymatic digest (SPD) containing soy-deprestatin, which is a soy-derived peptide with reported antidepressant-like effects, as well as its ability to mitigate oxidative stress in the brain caused by sub-chronic restraint stress. Mice were divided into two groups: a control group and restraint stress group. The restraint stress group was further divided into two groups administered water or SPD. After repeated short-time restraints over five days, we evaluated immobility times in the tail suspension test, and antioxidant enzyme activities, glutathione levels, oxidative stress maker levels, and the gene expression levels of Nrf2 and antioxidant enzymes in the brain. The results obtained showed that the oral administration of SPD reduced immobility times in mice exposed to restraint stress. In comparisons with the water-treated restraint group, the administration of SPD restored superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and glutathione levels and prevented restraint stress-induced increases in malondialdehyde, carbonyl protein, and 8-OHdG levels in the restraint stress group. In addition, high expression levels of Nrf2, HO-1, NQO-1 and GCLC were observed in the SPD-treated restraint group. These results suggest that SPD attenuated repeated restraint stress-induced depression-like behaviors by mitigating oxidative stress through the activation of the Nrf2 signaling pathway.

Niuhuang Qingxin Wan ameliorates depressive-like behaviors and improves hippocampal neurogenesis through modulating TrkB/ERK/CREB signaling pathway in chronic restraint stress or corticosterone challenge mice.

Introduction: Chronic stress-associated hormonal imbalance impairs hippocampal neurogenesis, contributing to depressive and anxiety behaviors. Targeting neurogenesis is thus a promising antidepressant therapeutic strategy. Niuhuang Qingxin Wan (NHQXW) is an herbal formula for mental disorders in Traditional Chinese Medicine (TCM) practice, but its anti-depressant efficacies and mechanisms remain unverified. Methods: In the present study, we tested the hypothesis that NHQXW could ameliorate depressive-like behaviors and improve hippocampal neurogenesis by modulating the TrkB/ERK/CREB signaling pathway by utilizing two depression mouse models including a chronic restraint stress (CRS) mouse model and a chronic corticosterone (CORT) stress (CCS) induced mouse model. The depression-like mouse models were orally treated with NHQXW whereas fluoxetine was used as the positive control group. We evaluated the effects of NHQXW on depressive- and anxiety-like behaviors and determined the effects of NHQXW on inducing hippocampal neurogenesis. Results: NHQXW treatment significantly ameliorated depressive-like behaviors in those chronic stress mouse models. NHQXW significantly improved hippocampal neurogenesis in the CRS mice and CCS mice. The potential neurogenic mechanism of NHQXW was identified by regulating the expression levels of BDNF, TrkB, p-ERK (T202/T204), p-MEK1/2 (S217/221), and p-CREB (S133) in the hippocampus area of the CCS mice. NHQXW revealed its antidepressant and neurogenic effects that were similar to fluoxetine. Moreover, NHQXW treatment revealed long-term effects on preventing withdrawal-associated rebound symptoms in the CCS mice. Furthermore, in a bioactivity-guided quality control study, liquiritin was identified as one of the bioactive compounds of NHQXW with the bioactivities of neurogenesis-promoting effects. Discussion: Taken together, NHQXW could be a promising TCM formula to attenuate depressive- and anxiety-like behaviors against chronic stress and depression. The underlying anti-depressant mechanisms could be correlated with its neurogenic activities by stimulating the TrkB/ERK/CREB signaling pathway.

A novel dual serotonin transporter and M-channel inhibitor D01 for antidepression and cognitive improvement

Cognitive dysfunction is a core symptom common in psychiatric disorders including depression that is primarily managed by antidepressants lacking efficacy in improving cognition. In this study, we report a novel dual serotonin transporter and voltage-gated potassium Kv7/KCNQ/M-channel inhibitor D01 (a 2-methyl-3-aryloxy-3-heteroarylpropylamines derivative) that exhibits both anti-depression effects and improvements in cognition. D01 inhibits serotonin transporters (Ki = 30.1 ± 6.9 nmol/L) and M channels (IC50 = 10.1 ± 2.4 μmol/L). D01 also reduces the immobility duration in the mouse FST and TST assays in a dose-dependent manner without a stimulatory effect on locomotion. Intragastric administrations of D01 (20 and 40 mg/kg) can significantly shorten the immobility time in a mouse model of chronic restraint stress (CRS)-induced depression-like behavior. Additionally, D01 dose-dependently improves the cognitive deficit induced by CRS in Morris water maze test and increases the exploration time with novel objects in normal or scopolamine-induced cognitive deficits in mice, but not fluoxetine. Furthermore, D01 reverses the long-term potentiation (LTP) inhibition induced by scopolamine. Taken together, our findings demonstrate that D01, a dual-target serotonin reuptake and M channel inhibitor, is highly effective in the treatment-resistant depression and cognitive deficits, thus holding potential for development as therapy of depression with cognitive deficits.

The impact of electroacupuncture on anxiety-like behavior and gut microbiome in a mouse model of chronic restraint stress.

Electroacupuncture (EA) is a beneficial physiotherapy approach for addressing neuropsychiatric disorders. Nevertheless, the impact of EA on the gut microbiome in relation to anxiety disorders remains poorly understood. To address this gap, we conducted a study using a chronic restraint stress (CRS) mouse model to investigate the anti-anxiety outcome of EA and its influence on gut microbiota. Our research involved behavioral tests and comprehensive sequencing of full-length 16S rRNA microbiomes. Our findings revealed that CRS led to significant anxiety-like behaviors and an imbalance in the gut microbiota. Specifically, we identified 13 species that exhibited changes associated with anxiety-like behaviors. Furthermore, EA partially alleviated both behaviors related to anxiety and the dysbiosis induced by CRS. In summary, this study sheds light on the alterations in gut microbiota species resulting from CRS treatment and brings new light into the connection between EA's anti-anxiety effects and the gut microbiota.

Effect of oral administration of bovine lactoferrin on the pulmonary immune response in a mouse model of restraint stress

Effect of oral administration of bovine lactoferrin on the pulmonary immune response in a mouse model of restraint stress

Engeletin alleviates depression-like phenotype by increasing synaptic plasticity via the BDNF-TrkB-mTORC1 signalling pathway.

Major depressive disorder (MDD) is a severe mental disorder associated with high rates of morbidity and mortality. Current first-line pharmacotherapies for MDD are based on enhancement of monoaminergic neurotransmission, but these antidepressants are still insufficient and produce significant side-effects. Consequently, the development of novel antidepressants and therapeutic targets is desired. Engeletin, a natural Smilax glabra rhizomilax derivative, is a compound with proven efficacy in treating ischemic stroke, yet its therapeutic effects and mechanisms for depression remain unexplored. The effects of engeletin were assessed in the forced swimming test (FST) and tail suspension test (TST) in mice. Engeletin was also investigated in the chronic restraint stress (CRS) mouse model of depression with fluoxetine (FLX) as the positive control. Changes in prefrontal cortex (PFC) spine density, synaptic plasticity-linked protein expressions and the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB)- mammalian target of rapamycin complex 1 (mTORC1) signalling pathway after chronic stress and engeletin treatment were then investigated. The TrkB and mTORC1 selective inhibitors, ANA-12 and rapamycin, respectively, were utilized to assess the engeletin's antidepressive mechanisms. Our data shows that engeletin exhibited antidepressant-like activity in the FST and TST in mice without affecting locomotor activity. Furthermore, it exhibited efficiency against the depression of CRS model. Moreover, it enhanced the BDNF-TrkB-mTORC1 pathway in the PFC during CRS and altered the reduction in dendritic spine density and levels of synaptic plasticity-linked protein induced by CRS. In conclusion, engeletin has antidepressant activity via activation of the BDNF-TrkB-mTORC1 signalling pathway and upregulation of PFC synaptic plasticity.

Restorative effect of NitroSynapsin on synaptic plasticity in an animal model of depression

In the search for new options for the pharmacological treatment of major depressive disorder, compounds with a rapid onset of action and high efficacy but lacking a psychotomimetic effect are of particular interest. In the present study, we evaluated the antidepressant potential of NitroSynapsin (NS) at behavioural, structural, and functional levels. NS is a memantine derivative and a dual allosteric N-methyl-d-aspartate receptors (NMDAR) antagonist using targeted delivery by the aminoadamantane of a warhead nitro group to inhibitory redox sites on the NMDAR. In a chronic restraint stress (CRS) mouse model of depression, five doses of NS administered on three consecutive days evoked antidepressant-like activity in the chronically stressed male C57BL/6J mice, reversing CRS-induced behavioural disturbances in sucrose preference and tail suspension tests. CRS-induced changes in morphology and density of dendritic spines in cerebrocortical neurons in the medial prefrontal cortex (mPFC) were also reversed by NS. Moreover, CRS-induced reduction in long-term potentiation (LTP) in the mPFC was found to be prevented by NS based on the electrophysiological recordings. Our study showed that NS restores structural and functional synaptic plasticity and reduces depressive behaviour to the level found in naïve animals. These results preliminarily revealed an antidepressant-like potency of NS.

Acute stress modulates the outcome of traumatic brain injury-associated gene expression and behavioral responses.

Psychological stress and traumatic brain injury (TBI) result in long-lasting emotional and behavioral impairments in patients. So far, the interaction of psychological stress with TBI not only in the brain but also in peripheral organs is poorly understood. Herein, the impact of acute stress (AS) occurring immediately before TBI is investigated. For this, a mouse model of restraint stress and TBI was employed, and their influence on behavior and gene expression in brain regions, the hypothalamic-pituitary-adrenal (HPA) axis, and peripheral organs was analyzed. Results demonstrate that, compared to single AS or TBI exposure, mice treated with AS prior to TBI showed sex-specific alterations in body weight, memory function, and locomotion. The induction of immediate early genes (IEGs, e.g., c-Fos) by TBI was modulated by previous AS in several brain regions. Furthermore, IEG upregulation along the HPA axis (e.g., pituitary, adrenal glands) and other peripheral organs (e.g., heart) was modulated by AS-TBI interaction. Proteomics of plasma samples revealed proteins potentially mediating this interaction. Finally, the deletion of Atf3 diminished the TBI-induced induction of IEGs in peripheral organs but left them largely unaltered in the brain. In summary, AS immediately before brain injury affects the brain and, to a strong degree, also responses in peripheral organs.

Upregulation of HDAC9 in hippocampal neurons mediates depression-like behaviours by inhibiting ANXA2 degradation

Major depressive disorder (MDD) is a pervasive and devastating mental disease. Broad spectrum histone deacetylase (HDAC) inhibitors are considered to have potential for the treatment of depressive phenotype in mice. However, due to its non-specific inhibition, it has extensive side effects and can not be used in clinical treatment of MDD. Therefore, finding specific HDAC subtypes that play a major role in the etiology of MDD is the key to develop corresponding specific inhibitors as antidepressants in the future. Copy number variation in HDAC9 gene is thought to be associated with the etiology of some psychiatric disorders. Herein, we found that HDAC9 was highly expressed in the hippocampus of chronic restraint stress (CRS) mouse model of depression. Upregulation of HDAC9 expression in hippocampal neurons of mice induced depression-like phenotypes, including anhedonia, helplessness, decreased dendritic spine density, and neuronal hypoexcitability. Moreover, knockdown or knockout of HDAC9 in hippocampal neurons alleviated depression-like phenotypes caused by chronic restraint stress (CRS) in WT mice. Importantly, using immunoprecipitation–mass spectrometry (IP–MS), we further found that Annexin A2 (ANXA2) was coupled to and deacetylated by HDAC9. This coupling resulted in the inhibition of ubiquitinated ANXA2 degradation and then mediates depression-like behavior. Overall, we discovered a previously unrecognized role for HDAC9 in hippocampal neurons in the pathogenesis of depression, indicating that inhibition of HDAC9 might be a promising clinical strategy for the treatment of depressive disorders.

Restraint stress-associated gastrointestinal injury and implications from the Evans blue-fed restraint stress mouse model.

The association between stress and gastrointestinal (GI) tract diseases is well established, while the exact mechanism remains elusive. As a result, it is urgent to establish mouse models to investigate restraint stress-associated GI leakage, but current models have their limitations. A new Evans blue-fed restraint mouse model has recently been developed that allows researchers to study restraint stress-associated GI leakage in live animals. This review article will focus on this model, including its mechanisms, clinical implications, and applications for studying restraint stress-associated GI injury. Recent findings from studies using this model will also be highlighted, along with their potential for diagnosis and treatment. The article aims to discuss about current research and provide recommendations for further study, ultimately improving our understanding of the link between stress and GI injury and improving patient outcomes.

Restraint Stress-Induced Immunosuppression Is Associated with Concurrent Macrophage Pyroptosis Cell Death in Mice.

Psychological stress is widely acknowledged as a major contributor to immunosuppression, rendering individuals more susceptible to various diseases. The complex interplay between the nervous, endocrine, and immune systems underlies stress-induced immunosuppression. However, the underlying mechanisms of psychological-stress-induced immunosuppression remain unclear. In this study, we utilized a restraint stress mouse model known for its suitability in investigating physiological regulations during psychological stress. Comparing it with cold exposure, we observed markedly elevated levels of stress hormones corticosterone and cortisol in the plasma of mice subjected to restraint stress. Furthermore, restraint-stress-induced immunosuppression differed from the intravenous immunoglobulin-like immunosuppression observed in cold exposure, with restraint stress leading to increased macrophage cell death in the spleen. Suppression of pyroptosis through treatments of inflammasome inhibitors markedly ameliorated restraint-stress-induced spleen infiltration and pyroptosis cell death of macrophages in mice. These findings suggest that the macrophage pyroptosis associated with restraint stress may contribute to its immunosuppressive effects. These insights have implications for the development of treatments targeting stress-induced immunosuppression, emphasizing the need for further investigation into the underlying mechanisms.

Electroacupuncture alleviates depression-like behaviours via a neural mechanism involving activation of Nucleus Accumbens Shell

Objectives This study investigated the effects of electroacupuncture (EA) on the depression-like behaviours in a mouse model of chronic restraint stress (CRS) and explored the underlying neural mechanisms. Methods Depression-like behaviours including sucrose preference test (SPT), open field test (OFT) and tail suspension test (TST) were carried out to evaluate the effects of CRS and EA treatment. Using immunohistochemistry to measure the expression of c-Fos. The Nucleus Accumbens Shell (NAc Shell) in C57BL/6J mice were activated or inhibited using Chemogenetics. Results All the CRS stimulated groups showed lower sucrose preference in the SPT and decreased centre times in the OFT, and increased immobility time in the TST when compared to the normal control. Interestingly, EA at LR3 or HT7 exerted anti-depressant effects, and LR3 EA exhibited a more significant restoration than HT7. Furthermore, EA at LR3 increased expression of c-Fos in the NAc Shell. Chemogenetic inhibition of NAc Shell blocked the effects of EA, whereas enhancement of NAc Shell activity profoundly reversed depressive phenotypes. Conclusions LR3 EA was effective in alleviating the depressive-like behaviours, and this therapeutic effect was associated with the activation of NAc Shell. Collectively, these findings revealed that EA may represent a promising therapeutic strategy for depression.

Gut microbial GABAergic signaling improves stress-associated innate immunity to respiratory viral infection

IntroductionEpidemiological evidences reveal that populations with psychological stress have an increased likelihood of respiratory viral infection involving influenza A virus (IAV) and SARS-CoV-2. ObjectivesThis study aims to explore the potential correlation between psychological stress and increased susceptibility to respiratory viral infections and how this may contribute to a more severe disease progression. MethodsA chronic restraint stress (CRS) mouse model was used to infect IAV and estimate lung inflammation. Alveolar macrophages (AMs) were observed in the numbers, function and metabolic-epigenetic properties. To confirm the central importance of the gut microbiome in stress-exacerbated viral pneumonia, mice were conducted through microbiome depletion and gut microbiome transplantation. ResultsStress exposure induced a decline in Lactobacillaceae abundance and hence γ-aminobutyric acid (GABA) level in mice. Microbial-derived GABA was released in the peripheral and sensed by AMs via GABAAR, leading to enhanced mitochondrial metabolism and α-ketoglutarate (αKG) generation. The metabolic intermediator in turn served as the cofactor for the epigenetic regulator Tet2 to catalyze DNA hydroxymethylation and promoted the PPARγ-centered gene program underpinning survival, self-renewing, and immunoregulation of AMs. Thus, we uncover an unappreciated GABA/Tet2/PPARγ regulatory circuitry initiated by the gut microbiome to instruct distant immune cells through a metabolic-epigenetic program. Accordingly, reconstitution with GABA-producing probiotics, adoptive transferring of GABA-conditioned AMs, or resumption of pulmonary αKG level remarkably improved AMs homeostasis and alleviated severe pneumonia in stressed mice. ConclusionTogether, our study identifies microbiome-derived tonic signaling tuned by psychological stress to imprint resident immune cells and defensive response in the lungs. Further studies are warranted to translate these findings, basically from murine models, into the individuals with psychiatric stress during respiratory viral infection.

Characterization of 2 Novel Phosphodiesterase 2 Inhibitors Hcyb1 and PF-05180999 on Depression- and Anxiety-Like Behavior.

Phosphodiesterase 2A (PDE2A) represents a novel target for new therapies addressing psychiatric disorders. To date, the development of PDE2A inhibitors suitable for human clinical evaluation has been hampered by the poor brain accessibility and metabolic stability of the available compounds. Corticosterone (CORT)-induced neuronal cell lesion and restraint stress mouse model were used to measure the neuroprotective effect in cells and antidepressant-like behavior in mice. The cell-based assay showed that both Hcyb1 and PF were potent in protecting cells against stress hormone CORT insults by stimulating cAMP and cGMP signaling in hippocampal cells (HT-22). Administration of both compounds before treatment of CORT to cells increased cAMP/cGMP, VASP phosphorylation at Ser239 and Ser157, cAMP response element binding protein phosphorylation at Ser133, and brain derived neurotrophic factor BDNF expression. Further in vivo study showed that both Hcyb1 and PF displayed -antidepressant- and anxiolytic-like effects against restraint stress as indicated by reduced immobility time in the forced swimming and tail suspension tasks as well as increased open arm entries and time spent in open arms and holes visit in elevated plus maze and hole-board tests, respectively. The biochemical study confirmed that these antidepressant- and anxiolytic-like effects of Hcyb1 and PF were related to cAMP and cGMP signaling in the hippocampus. The results extend the previous studies and validate that PDE2A is a tractable target for drug development in the treatment of emotional disorders such as depression and anxiety.

Circuit- and laminar-specific regulation of medial prefrontal neurons by chronic stress

BackgroundChronic stress exposure increases the risk of mental health problems such as anxiety and depression. The medial prefrontal cortex (mPFC) is a hub for controlling stress responses through communicating with multiple limbic structures, including the basolateral amygdala (BLA) and nucleus accumbens (NAc). However, considering the complex topographical organization of the mPFC neurons in different subregions (dmPFC vs. vmPFC) and across multiple layers (Layer II/III vs. Layer V), the exact effects of chronic stress on these distinct mPFC output neurons remain largely unknown.ResultsWe first characterized the topographical organization of mPFC neurons projecting to BLA and NAc. Then, by using a typical mouse model of chronic restraint stress (CRS), we investigated the effects of chronic stress on the synaptic activity and intrinsic properties of the two mPFC neuronal populations. Our results showed that there was limited collateralization of the BLA- and NAc-projecting pyramidal neurons, regardless of the subregion or layer they were situated in. CRS significantly reduced the inhibitory synaptic transmission onto the BLA-projecting neurons in dmPFC layer V without any effect on the excitatory synaptic transmission, thus leading to a shift of the excitation-inhibition (E-I) balance toward excitation. However, CRS did not affect the E-I balance in NAc-projecting neurons in any subregions or layers of mPFC. Moreover, CRS also preferentially increased the intrinsic excitability of the BLA-projecting neurons in dmPFC layer V. By contrast, it even caused a decreasing tendency in the excitability of NAc-projecting neurons in vmPFC layer II/III.ConclusionOur findings indicate that chronic stress exposure preferentially modulates the activity of the mPFC-BLA circuit in a subregion (dmPFC) and laminar (layer V) -dependent manner.

Antidepressant effects of p-coumaric acid isolated from Vaccinium bracteatum leaves extract on chronic restraint stress mouse model and antagonism of serotonin 6 receptor in vitro

BackgroundVaccinium bracteatum Thunb. leaves (VBL) are used in traditional herbal medicines to treat various biological diseases. p-coumaric acid (CA), the main active component of VBL, has neuroprotective effects against corticosterone-induced damage in vitro. However, the effects of CA on immobility induced by chronic restraint stress (CRS) in a mouse model and 5-HT receptor activity have not been investigated. Hypothesis/PurposeWe investigated the antagonistic effects of VBL, NET-D1602, and the three components of Gαs protein-coupled 5-HT receptors. Additionally, we identified the effects and mechanism of action of CA, the active component of NET-D1602, in the CRS-exposed model. MethodsFor in vitro analyses, we used 1321N1 cells stably expressing human 5-HT6 receptors and CHO-K1 expressing human 5-HT4 or 5-HT7 receptors cell lines to study the mechanism of action. For in vivo analyses, CRS-exposed mice were orally administered CA (10, 50, or 100 mg/kg) daily for 21 consecutive days. The effects of CA were analyzed by assessing behavioral changes using a forced swim test (FST), measuring levels of hypothalamic-pituitary-adrenal (HPA) axis-related hormones in ntial therapeutic effects as 5-HT6 receptor antagonists for neurodegenerative diseases and depressioserum, and acetylcholinesterase (AChE), monoamines, including 5-HT, dopamine, and norepinephrine, using enzyme-linked immunosorbent assay kits. The underlying molecular mechanisms of the serotonin transporter (SERT), monoamine oxidase A (MAO-A), and extracellular signal-regulated kinase (ERK)/protein kinase B (Akt)/mTORC1 signaling were detected using western blotting. ResultsCA was confirmed to be an active component in the antagonistic effects of NET-D1602 on 5-HT6 receptor activity through decreases in cAMP and ERK1/2 phosphorylation. Moreover, CRS-exposed mice treated with CA showed a significantly reduced immobility time in the FST. CA also significantly decreased corticosterone, corticotropin-releasing hormone (CRH), and adrenocorticotropic hormone (ACTH) levels. CA enhanced 5-HT, dopamine, and norepinephrine levels in the hippocampus (HC) and prefrontal cortex (PFC) but decreased MAO-A and SERT protein levels. Similarly, CA significantly upregulated the ERK, Ca2+/calmodulin-dependent protein kinase II (CaMKII), Akt/mTOR/p70S6K/S6 signaling pathways in both HC and the PFC. ConclusionCA contained in NET-D1602 may play the antidepressant effects against CRS-induced depression-like mechanism and the selective antagonist effect of 5-HT6 receptor.

IL-1 Mediates Chronic Stress-Induced Hyperalgesia Accompanied by Microglia and Astroglia Morphological Changes in Pain-Related Brain Regions in Mice

Chronic stress causes several pain conditions including fibromyalgia. Its pathophysiological mechanisms are unknown, and the therapy is unresolved. Since the involvement of interleukin-1 (IL-1) has been described in stress and inflammatory pain but no data are available regarding stress-induced pain, we studied its role in a chronic restraint stress (CRS) mouse model. Female and male C57Bl/6J wild-type (WT) and IL-1αβ-deficient (knock-out: IL-1 KO) mice were exposed to 6 h of immobilization/day for 4 weeks. Mechanonociception, cold tolerance, behavioral alterations, relative thymus/adrenal gland weights, microglia ionized calcium-binding adaptor molecule 1 (IBA1) and astrocyte glial fibrillary acidic protein (GFAP) integrated density, number and morphological transformation in pain-related brain regions were determined. CRS induced 15-20% mechanical hyperalgesia after 2 weeks in WT mice in both sexes, which was significantly reduced in female but not in male IL-1 KOs. Increased IBA1+ integrated density in the central nucleus of amygdala, primary somatosensory cortex hind limb representation part, hippocampus cornu ammonis area 3 (CA3) and periaqueductal gray matter (PAG) was present, accompanied by a cell number increase in IBA1+ microglia in stressed female WTs but not in IL-1 KOs. CRS induced morphological changes of GFAP+ astrocytes in WT but not in KO mice. Stress evoked cold hypersensitivity in the stressed animals. Anxiety and depression-like behaviors, thymus and adrenal gland weight changes were detectable in all groups after 2 but not 4 weeks of CRS due to adaptation. Thus, IL-1 mediates chronic stress-induced hyperalgesia in female mice, without other major behavioral alterations, suggesting the analgesic potentials of IL-1 in blocking drugs in stress-related pain syndromes.

Stress exacerbates pancreatic cancer both directly and indirectly by creating an immunosuppressive environment.

Sympathetic nerve stimulation by stress exacerbates various solid tumors, including pancreatic cancer (PCa). The relationship between cancer and immunity has been suggested; however, there is limited information about the effects of nerve stimulation on immunity and cancer. We aimed to investigate the involvement of sympathetic nerve stimulation in immune cells and its effects on PCa using a restraint stress mouse model. In the in vitro experiment, the mouse-derived PCa cell line (LTPA) was cultured in a noradrenalin-supplemented medium. In the in vivo experiment, mice were divided into non-stress and stress groups. LTPA proliferated significantly more when cultured in a noradrenalin-supplemented medium than in a normal medium. Flow cytometry analysis of blood immune cells revealed a significant decrease in B cells, T cells, and macrophages and a significant increase in myeloid-derived suppressor cells (MDSCs) in the stress group. Furthermore, a significant increase in blood noradrenaline levels was observed in the stress group (p< .01). In the PCa mice model, immune cells in the blood showed a similar trend, and the stress group had a poor prognosis. Furthermore, immunostaining at the tumor site showed that there was a lower number of B and T cells in the stress group. In addition, MDSCs were present at the tumor margins. These results suggest that sympathetic nerve stimulation is not only directly involved in PCa growth but also exacerbates PCa by creating an immunosuppressive environment in the blood and tumor tissue.