Chronic exercise improves repeated restraint stress-induced anxiety and depression through 5HT1A receptor and cAMP signaling in hippocampus

Gastrodin Ameliorates Post-Stroke Depressive-Like Behaviors Through Cannabinoid-1 Receptor-Dependent PKA/RhoA Signaling Pathway

Post-stroke depression (PSD) is a significant complication in stroke patients, increases long-term mortality, and exaggerates ischemia-induced brain injury. However, the underlying molecular mechanisms and effective therapeutic targets related to PSD have remained elusive. Here, we employed an animal behavioral model of PSD by combining the use of middle cerebral artery occlusion (MCAO) followed by spatial restraint stress to study the molecular underpinnings and potential therapies of PSD. Interestingly, we found that sub-chronic application of gastrodin (Gas), a traditional Chinese medicinal herb Gastrodia elata extraction, relieved depression-related behavioral deficits, increased the impaired expression of synaptic transmission-associated proteins, and restored the altered spine density in hippocampal CA1 of PSD animals. Furthermore, our results indicated that the anti-PSD effect of Gas was dependent on membrane cannabinoid-1 receptor (CB1R) expression. The contents of phosphorated protein kinase A (p-PKA) and phosphorated Ras homolog gene family member A (p(ser188)-RhoA) were decreased in the hippocampus of PSD-mice, which was reversed by Gas treatment, and CB1R depletion caused a diminished efficacy of Gas on p-PKA and p-RhoA expression. In addition, the anti-PSD effect of Gas was partially blocked by PKA inhibition or RhoA activation, indicating that the anti-PSD effect of Gas is associated with the CB1R-mediated PKA/RhoA signaling pathway. Together, our findings revealed that Gas treatment possesses protective effects against the post-stroke depressive-like state; the CB1R-involved PKA/RhoA signaling pathway is critical in mediating Gas's anti-PSD potency, suggesting that Gas application may be beneficial in the prevention and adjunctive treatment of PSD.

5-HT1A Receptors on Dentate Gyrus Granule Cells Confer Stress Resilience

BACKGROUND

Hyperactivity of granule cells in the ventral dentate gyrus (vDG) promotes vulnerability to chronic stress. However, which receptors in the vDG could be targeted to inhibit this hyperactivity and confer stress resilience is not known. The serotonin 1A receptor (5-HT1AR) is a Gi protein-coupled inhibitory receptor that has been implicated in stress adaptation, anxiety, depression, and antidepressant responses. 5-HT1ARs are highly expressed in the DG, but their potential to promote stress resilience by regulating granule cell activity has never been examined.

METHODS

We exposed male and female mice expressing 5-HT1ARs only in DG granule cells to 10 days of chronic social defeat stress (CSDS) and treated them with the 5-HT1AR agonist 8-OH-DPAT every day 30 minutes before each defeat throughout the CSDS paradigm. We then used whole-cell current clamp recordings, immunohistochemistry for the immediate early gene cFos, corticosterone immunoassays, and behavioral testing to determine how activating 5-HT1ARs on granule cells affects DG activity, neuroendocrine stress responses, and avoidance behavior.

RESULTS

We found that activating 5-HT1ARs hyperpolarized DG granule cells and reduced cFos+ granule cells in the vDG following CSDS, indicating that 5-HT1AR activation rescued stress-induced vDG hyperactivity. Moreover, 5-HT1AR activation dampened corticosterone responses to CSDS and prevented the development of stress-induced avoidance in the social interaction test and in the open field test.

CONCLUSIONS

Our findings show that activating 5-HT1ARs on DG granule cells can prevent stress-induced neuronal hyperactivity of the vDG and confer resilience to chronic stress.

Effect of high-intensity interval training on self-care and anxiety-like behaviors in naive rats

Self-care behavior covers individual's health, life and well-being to maintain the necessary activities. The aim of this study is to examine the self-care and possible anxiolytic effects of high-intensity interval exercise (HIIT). Eight-week-old Wistar Albino male rats were divided into Control (n = 8), and Exercise (n = 8). Rat exercised for 38 min a day, 5 days a week, for 8 weeks The animals were then subjected to open field test and splash test, and the behaviors were video recorded. Student t test and Shapiro-Wilk test were used as statistical tests. In the exercise group, spray-induced grooming behavior increased significantly in terms of duration and frequency (p < 0.05), but no significant difference was observed in the latency of grooming (p > 0.05). In the open-field test, the total distance traveled, which is a locomotor activity parameter, did not change between the groups. Anxiolytic-like behaviors such as total rearing behavior, unsupported rearing, central time, and central region entries increased remarkably in the exercise group vs. control (p < 0.0001). Freezing as an anxiogenic behavior decreased in the exercise group positively (p < 0.0001). Intermittent high-intensity exercise improved and increased self-care behaviors. Further, the present study shows that HIIT has beneficial effects on different aspects of behaviors such as exploratory behaviors, increasing anxiolytic behaviors, and reducing anxiogenic behavior. The present study is a preclinical study that will pave the way for new studies.

Possible role of exercise therapy on depression: Effector neurotransmitters as key players

About 280 million people suffer from depression as the most common neurological disorder and the most common cause of death worldwide. Exercise with serotonin released in the brain by the 5-HT3-IGF-1 mechanism can lead to antidepressant effects. Swimming exercise has antidepressant effects by increasing the sensitivity of serotonin 5-HT2 receptors and postsynaptic 5-HT1A receptors, increasing 5-HT and 5HIAA levels, increasing TPH and serotonin, and decreasing inflammatory levels of IFN-γ and TNF-α. Anaerobic and aerobic exercises increase beta-endorphin, enkephalin, and dynorphin and have antidepressant effects. Exercise by increasing dopamine, D1R, and D2R leads to the expression of BDNF and activation of TrkB and has antidepressant behavior. Exercise leads to a significant increase in GABAAR (γ2 and α2 subunits) and reduces neurodegenerative disorders caused by GABA imbalance through anti-inflammatory pathways. By increasing glutamate and PGC1α and reducing glutamatergic neurotoxicity, exercise enhances neurogenesis and synaptogenesis and prevents neurodegeneration and the onset of depression. Irisin release during exercise shows an important role in depression by increasing dopamine, BDNF, NGF, and IGF-1 and decreasing inflammatory mediators such as IL-6 and IL-1β. In addition, exercise-induced orexin and NPY can increase hippocampal neurogenesis and relieve depression. After exercise, the tryptophan to large neutral amino acids (TRP/LNAA) ratio and the tryptophan to branched-chain amino acids (BCAA) ratio increase, which may have antidepressant effects. The expression of M5 receptor and nAChR α7 increases after exercise and significantly increases dopamine and acetylcholine and ameliorates depression. It appears that during exercise, muscarinic receptors can reduce depression through dopamine in the absence of acetylcholine. Therefore, exercise can be used to reduce depression by affecting neurotransmitters, neuromodulators, cytokines, and/or neurotrophins.

Effects of exercise-targeted hippocampal PDE-4 methylation on synaptic plasticity and spatial learning/memory impairments in D-galactose-induced aging rats

Physical exercise reduces the effects of aging and cognitive decline by improving synaptic plasticity and spatial learning. However, the underlying neurobiological mechanisms are unclear. A total of 45 Male SPF Sprague-Dawley rats were acclimatized and then allocated into three groups, 15 in each group: the saline control (DC) group, D-gal-induced aging (DA) group, and D-gal-induced aging + exercise (DE) group. Six weeks of intraperitoneal injections of D-gal at a concentration of 100 mg/kg body weight/d was injected to establish model of aging in the DA and DE groups. Morris water maze test was implemented to evaluate the hippocampus related cognition. SOD activity and MDA was tested to assess the aging in all groups. H&E and Nissl staining was used to observe the histopathological changes of hippocampal neurons in aging rats. Quantitative real-time polymerase chain reaction, western blotting and immunofluorescence staining techniques were used to investigate the expression of synaptic genes and proteins in the hippocampus. Massarray methylation system was employed to measure the PDE-4 gene methylation level in rat hippocampal tissues. Our results demonstrated that exercise intervention improves cognitive function in D-gal-induced aging rats. The methylation of CpG sites in PDE-4 in the hippocampus was significantly increased. The physical exercise significantly increased PDE-4 gene methylation and effectively decreased PDE-4 gene and protein expression. These beneficial behavioral and morphological effects were attributed to PDE-4 methylation, which was activated cAMP/PKA/CREB pathway and improved synaptic plasticity. Exercise induced PDE-4 methylation is key mechanism underpinning the amelioration of learning/memory impairment, suggesting the potential efficacy of physical exercise training in delaying brain aging.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

Adulthood effects of developmental exercise in rats

Exercise is known to promote efficient function of stress circuitry. The developing brain is malleable and thus exercise during adolescence could potentially exert lasting beneficial effects on the stress response that would be detectable in adulthood. The current study determined whether adolescent wheel running was associated with reduced stress response in adulthood, 6 weeks after cessation of exercise. Male and female adolescent rats voluntarily ran for 6 weeks and then were sedentary for 6 weeks prior to 10 days of chronic restraint stress in adulthood. Fecal corticosterone levels were measured during stress, and escape from the restraint tube was assessed on the final day as a proxy for depressive-like behavior. Anxiety-like behavior was measured 24 h later with the elevated plus maze and locomotor behaviors with the open field. Brain and body measurements were taken immediately following behavioral testing. Developmental exercise and adulthood stress both exerted independent effects on physiological and behavioral outcomes in adulthood. Exercise history increased the odds ratio of escape from restraint stress in males, but did not influence other stress-induced behaviors. In summary, exercise early in life exerted lasting effects, but did not substantially alter the adulthood response to restraint stress.

Protection of p-Coumaric acid against chronic stress-induced neurobehavioral deficits in mice via activating the PKA-CREB-BDNF pathway

There is a body of evidence to suggest that chronic stress modulates neurochemical homeostasis, alters neuronal structure, inhibits neurogenesis and contributes to development of mental disorders. Chronic stress-associated mental disorders present common symptoms of cognitive impairment and depression with complex disease mechanisms. P-coumaric acid (p-CA), a natural phenolic compound, is widely distributed in vegetables, cereals and fruits. p-CA exhibits a wide range of health-related effects, including anti-oxidative-stress, anti-mutagenesis, anti-inflammation and anti-cancer activities. The current study aims to evaluate the therapeutic potential of p-CA against stress-associated mental disorders. We assessed the effect of p-CA on cognitive deficits and depression-like behavior in mice exposed to chronic restraint stress (CRS); we used network pharmacology, biochemical and molecular biological approaches to elucidate the underlying molecular mechanisms. CRS exposure caused memory impairments and depression-like behavior in mice; p-CA administration attenuated these CRS-induced memory deficits and depression-like behavior. Network pharmacology analysis demonstrated that p-CA was possibly involved in multiple targets and a variety of signaling pathways. Among them, the protein kinase A (PKA) - cAMP-response element binding protein (CREB) - brain derived neurotrophic factor (BDNF) signaling pathway was predominant and further characterized. The levels of PKA, phosphorylated CREB (pCREB) and BDNF were significantly lowered in the hippocampus of CRS mice, suggesting disruption of the PKA-CREB-BDNF signaling pathway; p-CA treatment restored the signaling pathway. Furthermore, CRS upregulated expression of proinflammatory cytokines in hippocampus, while p-CA reversed the CRS-induced effects. Our findings suggest that p-CA will offer therapeutic benefit to patients with stress-associated mental disorders.

Long noncoding RNA NONHSAG045500 regulates serotonin transporter to ameliorate depressive-like behavior via the cAMP-PKA-CREB signaling pathway in a model of perinatal depression

OBJECTIVE

Perinatal depression (PND) is the most common complication of childbirth and negatively affects the mother. Long noncoding RNA (lncRNA) NONHSAG045500 inhibits the expression of 5-hydroxytryptamine (5-HT) transporter (i.e. serotonin transporter [SERT]) and produces an antidepressant effect. This study aimed to identify a link between the lncRNA NONHSAG045500 and the pathogenesis of PND.

METHODS

Female C57BL/6 J mice were divided into normal control group (control group, n = 15), chronic unpredictable stress (CUS) model group (PND group, n = 15), lncRNA NONHSAG045500-overexpressed group (LNC group, sublingual intravenous injection of NONHSAG045500 overexpression cells for 7 days, n = 15), and escitalopram treatment group (i.e. the selective serotonin reuptake inhibitor [SSRI] group, with escitalopram administered from the 10th day after pregnancy to the 10th day after delivery, n = 15). Control group mice were conceived normally, whereas, in the other groups, a CUS model was established before mice were conceived. Depressive-like behaviour was assessed via sucrose preference, forced swimming, and open-field tests. The expression levels of 5-HT, SERT, and cAMP-PKA-CREB pathway-related proteins in the prefrontal cortex were detected on the 10th day after delivery.

RESULTS

Mice in the PND group exhibited significant depressive-like behaviours compared with those in the control group, indicating that the PND model was successfully established. The expression of lncRNA NONHSAG045500 was markedly decreased in the PND group compared with that in the control group. After treatment, both LNC and SSRI groups showed a significant improvement in depression-like behaviour, and the expression of 5-HT in the prefrontal cortex was increased in these groups compared with that in the PND group. In addition, the LNC group displayed lower expression of SERT and higher expression of cAMP, PKA, and CREB when in comparison to PND group.

CONCLUSION

NONHSAG045500 mediates the development of PND mainly by activating the cAMP-PKA-CREB pathway, increasing the level of 5-HT, and decreasing the expression of SERT.

The positive effects of positive coping on mental health in college students during the COVID-19 campus lockdown

Objectives

Isolation has been an effective method to control the spread of COVID-19 over the past 3 years. However, lifestyle changes may have a negative impact on mental health. To examine the effects of positive coping on mental health in college students during the COVID-19 campus lockdown, this study conducted an online cross-sectional survey.

Methods

In October 2022, following a prolonged campus lockdown of nearly 3 years, 313 university students from a university in Shandong Province, China, were invited to complete an online questionnaire. The questionnaire comprised a self-administered general situation questionnaire, the Simple Coping Style Scale, and the Hospital Depression and Anxiety Scale.

Results

(1) The analysis of variance revealed a significant main effect of coping Style on depression [F(4,300) = 2.446, p = 0.047] during the COVID-19 campus lockdown. A post-hoc test indicated that college students who engaged in study (p = 0.012) or sports (p = 0.027) during their free time had significantly lower depression scores than those who used the Internet. (2) Independent sample t-tests showed significant differences in positive and negative coping styles among college students in terms of depression (t = 6.891, p < 0.001) and anxiety scores (t = 7.745, p < 0.001). (3) Pearson correlation analysis demonstrated a negative correlation between positive coping style and anxiety (r = -0.378, p < 0.001), and between positive coping style and depression (r = 0.427, p < 0.001). Positive correlations were also found between the negative coping style and anxiety (r = 0.155, p = 0.007), and between the negative coping style and depression (r = 0.190, p < 0.001).

Discussion

The study suggested that fostering positive coping in students can mitigate mental health issues during crises, providing a blueprint for university mental health initiatives during epidemics.

Aerobic exercise regulates GPR81 signal pathway and mediates complement- microglia axis homeostasis on synaptic protection in the early stage of Alzheimer's disease

AIMS

Memory impairment is a major clinical manifestation in Alzheimer's disease (AD) patients, while regular exercise may prevent and delay degenerative changes in memory functions, and our aim is to explore the influence and molecular mechanisms of aerobic exercise on the early stages of Alzheimer's disease.

MAIN METHODS

3-month-old male APP/PS1 transgenic AD mice and C57BL/6J wild-type mice were randomly divided into four groups: wild-type and APP/PS1 mice with sedentary (WT-SED, AD-SED), and running (WT-RUN, AD-RUN) for 12-weeks. The spatial learning and memory function, RNA-sequencing, spine density, synaptic associated protein, mRNA and protein expression involved in G protein-coupled receptor 81 (GPR81) signaling pathway, and complement factors in brain were measured.

KEY FINDINGS

Aerobic exercise improved spatial learning and memory in APP/PS1 mice, potentially attributed to increased dendritic spine density. Subsequently, potential underlying mechanisms were identified through RNA sequencing: regular aerobic exercise could activate the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) cAMP/PKA signaling pathway and upregulate synaptic function-related proteins to promote synaptic growth, possibly by modulating GPR81. Notably, regular aerobic exercise inhibited microglial activation, reversed the microglial phenotype, reduced the production of initiation factor C1q and central factor C3 in the complement cascade in the brain, prevented the colocalization of microglia and PSD-95, and thus prevented synaptic loss.

SIGNIFICANCE

Physical exercise could play a critical role in improving cognitive function in AD by promoting synaptic growth and preventing synaptic loss, which may be related to the regulation of the GPR81/cAMP/PKA signaling pathway and inhibition of complement-mediated microglial phagocytosis of synapses.

Antidepressant-like Effects of Representative Types of Food and Their Possible Mechanisms

Depression is a mental disorder characterized by low mood, lack of motivation, negative cognitive outlook, and sleep problems. Suicide may occur in severe cases, although suicidal thoughts are not seen in all cases. Globally, an estimated 350 million individuals grapple with depression, as reported by the World Health Organization. At present, drug and psychological treatments are the main treatments, but they produce insufficient responses in many patients and fail to work at all in many others. Consequently, treating depression has long been an important topic in society. Given the escalating prevalence of depression, a comprehensive strategy for managing its symptoms and impacts has garnered significant attention. In this context, nutritional psychiatry emerges as a promising avenue. Extensive research has underscored the potential benefits of a well-rounded diet rich in fruits, vegetables, fish, and meat in alleviating depressive symptoms. However, the intricate mechanisms linking dietary interventions to brain function alterations remain largely unexplored. This review delves into the intricate relationship between dietary patterns and depression, while exploring the plausible mechanisms underlying the impact of dietary interventions on depression management. As we endeavor to unveil the pathways through which nutrition influences mental well-being, a holistic perspective that encompasses multidisciplinary strategies gains prominence, potentially reshaping how we approach and address depression.

In search of stress: analysis of stress-related markers in mice after hindlimb unloading and social isolation

OBJECTIVES

Hindlimb unloading (HU), widely used to simulate microgravity effects, is known to induce a stress response. However, as single-housed animals are usually used in such experiments, social isolation (SI) stress can affect experimental results. In the present study, we aimed to delineate stressful effects of 3-day HU and SI in mice.

METHODS

Three animal groups, HU, SI, and group-housed (GH) control mice, were recruited. A comprehensive analysis of stress-related markers was performed using ELISA, western blotting, and immunohistochemistry.

RESULTS

Our results showed that blood corticosterone and activity of glucocorticoid receptors and cAMP response element-binding protein (CREB) in the hippocampus of SI and HU animals did not differ from GH control. However, SI mice demonstrated upregulation of the hippocampal corticotropin-releasing hormone (CRH), inducible NO synthase (iNOS), vesicular glutamate transporter 1 (VGLUT1), and glutamate decarboxylases 65/67 (GAD65/67) along with activation of Fos-related antigen 1 (Fra-1) in the amygdala confirming the expression of stress. In HU mice, the same increase in GAD65/67 and Fra-1 indicated the contribution of SI. The special HU effect was expressed only in neurogenesis attenuation.

DISCUSSION

Thus, our data indicated that 3-day HU could not be characterized as physiological stress, but SI stress contributed to the negative effects of HU.

Implications of Physical Exercise on Episodic Memory and Anxiety: The Role of the Serotonergic System

There is a growing interest in investigating the effects of physical exercise on cognitive performance, particularly episodic memory. Similarly, an increasing number of studies in recent decades have studied the effects of physical activity on mood and anxiety disorders. Moreover, the COVID-19 pandemic has raised awareness of the importance of regular physical activity for both mental and physical health. Nevertheless, the exact mechanisms underlying these effects are not fully understood. Interestingly, recent findings suggest that the serotonergic system may play a key role in mediating the effects of physical exercise on episodic memory and anxiety. In this review, we discuss the impact of physical exercise on both episodic memory and anxiety in human and animal models. In addition, we explore the accumulating evidence that supports a role for the serotonergic system in the effects of physical exercise on episodic memory and anxiety.

Progress in the mechanism of acupuncture intervention on pain emotion and pain cognition mediated by limbic system

Pain is a complex physiological and psychological activity, involving at least three dimensions, including pain sensation, pain emotion, and pain cognition. Acupuncture can clearly relieve the pain sensation of patients and improve pain emotion and pain cognition induced by pain; acupuncture participates in the multi-dimensional regulation of pain through brain regions of the limbic system such as anterior cingulate cortex (ACC), amygdala (AMY), and hippocampus. By analyzing relevant literature, it has been found that the regulation of acupuncture on pain emotion is mainly related to the activation of pertinent opioid receptors in the ACC, the decrease of the expression of extracellular signal-regulated kinase (ERK), and the promotion of the expression of glutamic acid (Glu) A1, metabotropic glutamate receptor-1 (mGluR1), and γ-aminobutyric acid aminobutyric acid (GABA) B2 protein in the AMY. The regulation of acupuncture on pain cognition is mainly related to the elevation of the expression of protein kinase A (PKA) and phospho-p38 mitogen-activated protein kinase (phospho-p38 MAPK) and the inhibition of cyclic adenosine monophosphate (cAMP)/PKA/cAMP response element-binding protein (CREB) signaling pathway in the ACC.

Study on lifestyle habits affecting sleep disorders at the undergraduate education stage in Xuzhou City, China

Background

In China, undergraduate students face both academic and career selection pressures, sleep is an important physiological process for them. Investigate the physical exercise, sleep quality of undergraduate students in the education stage in Xuzhou City, and analyze the factors affecting their sleep quality, to promote the health education and psychological health of undergraduate students.

Materials and methods

The Physical Activity Rating Scale-3 (PARS-3), the Pittsburgh Sleep Quality Index (PSQI), and the demographic information questionnaire were used to survey a whole-group sample of four undergraduate colleges and universities (Xuzhou Institute of Engineering, Xuzhou Medical University, China University of Mining and Technology, Jiangsu Normal University) in Xuzhou by cluster sampling, the general characteristics including gender, grade, height, weight, domicile, race, economic income, etc., were collected, and the data were analyzed and processed using chi-square tests and multi-factor logistic regression.

Results

3,366 valid questionnaires were collected from four undergraduate colleges and universities, including 1,355 males and 2,011 females. The detection rate of exercise in Jiangsu Normal University was lower than that in other universities, and the detection rate of sleep disorders was higher than that in other universities. Xuzhou Medical University, the highest detection rate of large exercise, Xuzhou Institute of Technology, the lowest detection rate of sleep disorders. There were significant differences in the detection rate of large amount of exercise among college students of different genders, grades, body types, and majors (χ2 = 259.172, P < 0.001; χ2 = 34.473, P < 0.001; χ2 = 36.026, P < 0.001; χ2 = 57.908, P < 0.001). There were significant differences in the detection rate of sleep disorders among college students with different gender, grade, family economic status, daily cell phone use time, cell phone purposeless usage, and exercise level (χ2 = 5.806, P = 0.016; χ2 = 47.5, P < 0.001; χ2 = 28.949, P < 0.001; χ2 = 55.866, P < 0.001; χ2 = 147.101, P < 0.001; χ2 = 9.129, P = 0.010). Multivariate logistic regression analysis showed that grade, family economic status, cell phone use time, cell phone purposeless usage is the main influencing factors of sleep disorders in college students.

Conclusion

The sleep problems of undergraduates are serious, especially in Jiangsu Normal University. Scientific and appropriate exercise is an important measure to solve the sleep problems of undergraduates. Colleges and universities should actively carry out health education, college students living habits such as cell phone use should be guided training.

The Relationship between Physical Exercise and Negative Emotions in College Students in the Post-Epidemic Era: The Mediating Role of Emotion Regulation Self-Efficacy

OBJECTIVE

To investigate the relationship between physical activity and negative emotions among college students in the post-epidemic era and determine if emotional regulation plays a mediating role between physical activity and negative emotions.

METHODS

479 college students (293 males, 186 females, M = 19.94, SD = 1.25) who were under closed campus management during the epidemic period were surveyed using the physical activity rating scale (PARS-3), the self-assessment scale for anxiety (SAS), the self-esteem scale for depression (SDS), and the emotion regulation self-efficacy scale (RES).

RESULTS

(1) Physical activity, negative emotions, and emotion regulation self-efficacy among college students were significantly different by gender (p < 0.01). (2) Physical exercise was negatively correlated with anxiety and depression (r = -0.236, p < 0.01; r = -0.198, p < 0.01) and positively correlated with emotion regulation self-efficacy (r = 0.256, p < 0.01) in college students. (3) Emotion regulation self-efficacy was negatively correlated with anxiety and depression (r = -0.440, p < 0.01; r = -0.163, p < 0.01). (4) Emotion regulation self-efficacy also partially mediated the relationship between physical activity and negative emotions.

CONCLUSION

(1) Physical activity in the post-epidemic era negatively predicted anxiety and depression in school-isolated college students. (2) Emotion regulation self-efficacy in the post-epidemic era partially mediates the relationship between physical activity and anxiety and depression.

Role of CRF1 and CRF2 receptors in the lateral hypothalamus in cardiovascular and anxiogenic responses evoked by restraint stress in rats: Evaluation of acute and chronic exposure

We investigated the role of corticotropin-releasing factor (CRF) neurotransmission within the lateral hypothalamus (LH) in cardiovascular and anxiogenic-like responses evoked by acute and repeated restraint stress in rats. For this, animals were subjected to intra-LH microinjection of a selective CRF₁ (CP376395) or CRF₂ (antisauvagine-30) receptor antagonist before either an acute or the 10th session of restraint stress. Restraint-evoked arterial pressure and heart rate increases, tail skin temperature decrease and anxiogenic-like effect in the elevated plus maze (EPM) were evaluated. We also assessed the effect of 10 daily sessions of restraint on expression of CRF₁ and CRF₂ receptors within the LH. We identified that antagonism of either CRF₁ or CRF₂ receptor within the LH decreased the tachycardia during both the acute and 10th session of restraint, but the effect of the CRF₁ receptor antagonist was more pronounced during the 10th session. Acute restraint stress also caused anxiogenic-like effect, and this response was inhibited in animals treated with either CP376395 or antisauvagine-30. Anxiety-like behaviors were not changed following the 10th session of restraint, and pharmacological treatments did not affect the behavior in the EPM in chronically stressed animals. Repeated restraint also did not change the level of the CRF receptors within the LH. Taken together, the findings indicate that CRF₁ and CRF₂ receptors within the LH are involved in tachycardic and anxiogenic-like responses to aversive stimuli. Control of tachycardia by the CRF₁ receptor is sensitized by previous stressful experience, and this effect seems to be independent of changes in expression of the receptor.

VTA-projecting cerebellar neurons mediate stress-dependent depression-like behaviors

Although cerebellar alterations have been implicated in stress symptoms, the exact contribution of the cerebellum to stress symptoms remains to be elucidated. Here, we demonstrated the crucial role of cerebellar neurons projecting to the ventral tegmental area (VTA) in the development of chronic stress-induced behavioral alterations in mice. Chronic chemogenetic activation of inhibitory Purkinje cells in crus I suppressed c-Fos expression in the DN and an increase in immobility in the tail suspension test or forced swimming test, which were triggered by chronic stress application. The combination of adeno-associated virus-based circuit mapping and electrophysiological recording identified network connections from crus I to the VTA via the dentate nucleus (DN) of the deep cerebellar nuclei. Furthermore, chronic inhibition of specific neurons in the DN that project to the VTA prevented stressed mice from showing such depression-like behavior, whereas chronic activation of these neurons alone triggered behavioral changes that were comparable with the depression-like behaviors triggered by chronic stress application. Our results indicate that the VTA-projecting cerebellar neurons proactively regulate the development of depression-like behavior, raising the possibility that cerebellum may be an effective target for the prevention of depressive disorders in human.

The mediating role of resilience in the effects of physical exercise on college students' negative emotions during the COVID-19 epidemic

Due to its suddenness and unpredictability, COVID-19 caused strife and effects on public mental health, resulting in a surge of negative emotions. The study explores the relationship between physical exercise and negative emotions in home-based college students during the COVID-19 epidemic, as well as the mediating role of resilience, thus providing a new basis for understanding the role of physical exercise in improving negative emotions in college students; A total of 1214 college students were investigated with the Physical Exercise Questionnaire, Negative Emotion Scale and Resilience Scale; Both physical exercise and resilience were significantly negatively correlated with negative emotions in college students (r = - 0.25, - 0.33, P < 0.001), and there was a significant positive correlation between physical exercise and resilience (r = 0.47, P < 0.001). Physical exercise had a direct effect on the negative emotions of college students (β = - 0.14, P < 0.001). Resilience had a partial mediating effect between physical exercise and the negative emotions of the college students, with a mediating effect value of 0.14 and a mediating effect contribution rate of 50.00%; The study found that physical exercise not only directly affected the negative emotions of college students but also improved their resilience by slowing down their negative emotions and promoting their mental health.

Maternal high-fat diet increases anhedonic behavior and modulates hippocampal Mash1 and BDNF expression in adult offspring

BACKGROUND

The consumption of a high-fat diet (HFD) during pregnancy and perinatal periods can lead to long-term effects in the offspring central nervous system, affecting pathways related to neurogenesis and behavior, and increasing predispositions to depressive and anxiety-like behaviors. Thus, this study aimed to investigate the effects of a maternal HFD on the hippocampi of adult offspring and behaviors related to anxiety and depression.

METHODS

The protein and mRNA expression of the brain-derived neurotrophic factor (BDNF), Mash1, Notch1, Hes5, serotonin transporter (SERT), 5-HT1A serotonergic receptor (5-HT1A), tryptophan hydroxylase 2 (TPH2, key enzyme of serotonin synthesis), JNK and pJNK were analyzed in the hippocampi of male Swiss mice. Hippocampal serotonin levels were measured using ELISA. The lipid peroxidation, total oxidant status, total antioxidant status, and GSH/GSSG were evaluated as oxidative stress measures. For the behavioral analysis, the open field, elevated plus maze, and sucrose preference tests were used.

RESULTS

Maternal HFD led to increased body weight in dams and their offspring, as well as altered body composition and LDL levels in the offspring. There were no alterations in oxidative stress or JNK phosphorylation. Hippocampal Mash1 and BDNF expression were altered in HFD offspring. The HFD offspring exhibited anhedonic behavior.

CONCLUSION

These findings suggest that maternal HFD leads to long-term alterations in the offspring's neurotrophic systems, impairing their behavior.

Therapeutic Potential of Curcumin in Reversing the Depression and Associated Pseudodementia via Modulating Stress Hormone, Hippocampal Neurotransmitters, and BDNF Levels in Rats

Depressive state adversely affects the memory functions, especially in the geriatric population. The initial stage of memory deficits associated with depression is particularly called as pseudodementia. It is the starting point of memory disturbance before dementia. The purpose of this research was to study depression and its consequent pseudodementia. For this purpose 24 male albino Wistar rats were divided into four groups. Depression was induced by 14 days of chronic restraint stress (CRS) daily for 4 h. After developing a depression model, pattern separation test was conducted to monitor pseudodementia in rats. Morris water maze test (MWM) was also performed to observe spatial memory. It was observed that model animals displayed impaired pattern separation and spatial memory. Treatment was started after the development of pseudodementia in rats. Curcumin at a dose of 200 mg/kg was given to model rats for one week along with the stress procedure. Following the treatment with curcumin, rats were again subjected to the aforementioned behavioral tests before decapitation. Corticosterone levels, brain derived neurotrophic factor (BDNF) and neurochemical analysis were conducted. Model rats showed depressogenic behavior and impaired memory performance. In addition to this, high corticosterone levels and decreased hippocampal BDNF, 5-HT, dopamine (DA), and acetylcholine (ACh) levels were also observed in depressed animals. These behavioral biochemical and neurochemical changes were effectively restored following treatment with curcumin. Hence, it is suggested from this study that pseudodementia can be reversed unlike true dementia by controlling the factors such as depression which induce memory impairment.

Biased agonism in drug discovery: Is there a future for biased 5-HT1A receptor agonists in the treatment of neuropsychiatric diseases?

Serotonin (5-HT) is one of the fundamental neurotransmitters that contribute to the information essential for an organism's normal, physiological function. Serotonin acts centrally and systemically. The 5-HT_1A receptor is the most widespread serotonin receptor, and participates in many brain-related disorders, including anxiety, depression, and cognitive impairments. The 5-HT_1A receptor can activate several different biochemical pathways and signals through both G protein-dependent and G protein-independent pathways. Preclinical experiments indicate that distinct signaling pathways in specific brain regions may be crucial for antidepressant-like, anxiolytic-like, and procognitive responses. Therefore, the development of new ligands that selectively target a particular signaling pathway(s) could open new possibilities for more effective and safer pharmacotherapy. This review discusses the current state of preclinical studies focusing on the concept of functional selectivity (biased agonism) regarding the 5-HT_1A receptor and its role in antidepressant-like, anxiolytic-like, and procognitive regulation. Such work highlights not only the differential effects of targeted autoreceptors, vs. heteroreceptors, but also the importance of targeting specific downstream intracellular signaling processes, thereby enhancing favorable over unfavorable signaling activation.

Beneficial effects of vitamin D on anxiety and depression-like behaviors induced by unpredictable chronic mild stress by suppression of brain oxidative stress and neuroinflammation in rats

The objective of this study was to investigate the protective effects of vitamin D (Vit D) on anxiety and depression-like behaviors induced by unpredictable chronic mild stress and brain tissue oxidative damage criteria and neuroinflammation in rats. The rats were treated as follows: (1) control, (2) UCMS, (3-5) Vit D 100, 1000, and 10,000 iu + UCMS. Rats were subjected to UCMS for a total of 4 weeks. During week 4, they received seven training trials. The brains were then collected to examine inflammation and oxidative stress criteria. Pretreatment with Vit D enhanced performances of the rats in the elevated plus maze (EPM) and open field (OF) and forced swimming test (FST). UCMS also increased MDA and interleukin-6 (IL-6) levels while decreased CAT, SOD, and thiol. Vit D reversed the effects of UCMS. The results of the current research revealed that Vit D improved UCMS-induced anxiety and depression via decreasing brain oxidative stress and inhibiting neuroinflammation.

Involvement of 5-HT-BDNF signaling axis in mediating synergistic antidepressant-like effects after combined administration of two oligosaccharide esters

Potential mechanisms of depression involving herbal medicines and their specific compounds include elevated 5-HT level and downstream BDNF pathway. To identify potentially new combined therapeutic strategies, 3,6'-disinapoylsucrose (DISS) and tenuifoliside A (TFSA) have been observed to show antidepressant-like effects and its related 5-HT-BDNF pathway. We have tried to investigate whether combined administration of DISS and TFSA exerted more effective in the treatment of depression, as assessed through tail suspension test (TST) and forced swimming test (FST). In addition, we also analyzed the expression of three important proteins, cyclic adenosine monophosphate (cAMP) response element binding (CREB), brain-derived neurotrophic factor (BDNF), and cAMP-regulated transcriptional coactivators (CRTC1), which have been shown to be involved in the regulation of the neurotrophic factors in the hippocampus. The DISS and TFSA separately, both at a dose of 5 mg/kg each, displayed small effect in the immobility time. However, combined treatment of these two in multiple doses exhibited better effect. Moreover, combined treatment of DISS and TFSA also demonstrated enhanced levels of 5-hydroxytryptamine (5-HT), and stronger increase in the phosphorylation levels of CREB, BDNF, and CRTC1 proteins in the hippocampus. Overall, our results indicated that coadministration of these two oligosaccharide esters at low dose may induce more pronounced antidepressant activity, in comparison with individual treatment even at high dosage. Thus, the antidepressant properties of both these compounds can be attributed to their ability to influence 5-HT and BDNF pathway, and thereby suggesting that this combination strategy can definitely act as alternative therapy for depression disorder with very limited side effects.

Effects of running before pregnancy on long-term memory and hippocampal alterations induced by prenatal stress

Studies have shown that an adverse environment in utero influences fetal growth and development, leading to several neuroendocrine and behavioral changes in adult life. Nevertheless, the mechanisms involved in the long-term benefits of pregestational exercise are still poorly understood. Thus, this study aimed to evaluate the effects of physical exercise before the gestational period on memory behavior and gene expression in the hippocampus of adult mice submitted to prenatal stress. Female Balb/c mice were divided into three groups: control (CON), prenatal restraint stress (PNS), and exercise before the gestational period plus PNS (EX + PNS). When adults, male and female offspring were submitted to the object recognition test followed by the hippocampal evaluation of BDNF exons I and IV mRNA expression, as well as hypothalamic-pituitary-adrenal axis related genes. Pregestational exercise did not prevent the decreased recognition index, as well as GR and CRHR1 gene expression observed in PNS males. Conversely, prenatal stress did not influence female memory behavior. Moreover, exercise attenuated the effects of prenatal stress on female BDNF IV gene expression. The results indicate that pregestational exercise was able to prevent the effects of maternal stress on hippocampal BDNF IV gene expression in females, although no effects were seen on the stress-induced memory impairment in males.

Morphofunctional State of the Large Intestine in Rats under Conditions of Restraint Stress and Administration of Peptide ACTH(4-7)-PGP (Semax)

We studied the effect of intraperitoneal administration ACTH_(4-7)-PGP in doses of 5, 50, 150, and 450 μg/kg to Wistar male rats 12-15 min before modeling restraint stress on the morphofunctional state of the colon. In rats exposed to restraint stress, signs of atrophy and inflammatory reaction in the colon wall, changes in functional activity and number of mast cells, and increased serum level of corticosterone were observed. Administration of the peptide led to a decrease in corticosterone concentration, alleviated stress-induced pathomorphological changes, and promoted adaptation of the intestinal wall to stress. The positive effects of ACTH_(4-7)-PGP can be determined by multifunctional nature of the physiological and pharmacological effects of the neuropeptide.

Composition of Colon Microbiota in Rats Treated with ACTH(4-7)-PGP Peptide (Semax) under Conditions of Restraint Stress

We studied the effect of Semax on the state of intestinal microbiota in rats subjected to restraint stress. Semax was injected to Wistar male rats intraperitoneally in doses of 5, 50, 150, 450 μg/kg 12-15 min before modelling chronic restraint stress. It was found that stress exposure reduced the number of obligate bacteria in the colon microbiota, but increased the content of opportunistic microorganisms. Semax in doses of 50 and 150 μg/kg prevented the stress-induced changes in the composition of colon microbiota. The observed effects of Semax might be mediated by the central neurotropic effects as well as by binding to peripheral melanocortin receptors of the intestine.

Exploring the impact of trauma type and extent of exposure on posttraumatic alterations in 5-HT1A expression

The long-term behavioral, psychological, and neurobiological effects of exposure to potentially traumatic events vary within the human population. Studies conducted on trauma-exposed human subjects suggest that differences in trauma type and extent of exposure combine to affect development, maintenance, and treatment of a variety of psychiatric syndromes. The serotonin 1-A receptor (5-HT1A) is an inhibitory G protein-coupled serotonin receptor encoded by the HTR1A gene that plays a role in regulating serotonin release, physiological stress responding, and emotional behavior. Studies from the preclinical and human literature suggest that dysfunctional expression of 5-HT1A is associated with a multitude of psychiatric symptoms commonly seen in trauma-exposed individuals. Here, we synthesize the literature, including numerous preclinical studies, examining differences in alterations in 5-HT1A expression following trauma exposure. Collectively, these findings suggest that the impact of trauma exposure on 5-HT1A expression is dependent, in part, on trauma type and extent of exposure. Furthermore, preclinical and human studies suggest that this observation likely applies to additional molecular targets and may help explain variation in trauma-induced changes in behavior and treatment responsivity. In order to understand the neurobiological impact of trauma, including the impact on 5-HT1A expression, it is crucial to consider both trauma type and extent of exposure.

Electroacupuncture ameliorates learning and memory deficits via hippocampal 5-HT1A receptors and the PKA signaling pathway in rats with ischemic stroke

Hippocampal 5-HT1A receptors and the PKA signaling pathway have been implicated in learning and memory. This study aimed to investigate whether PKA signaling mediated by 5-HT1A receptors was involved in the electroacupuncture (EA)-mediated learning and memory in a rat model of middle cerebral artery occlusion-induced cognitive deficit (MICD). Compared to no treatment or non-acupoint EA treatment, EA at DU20 and DU24 acupoints improved the neurological deficit of scores, shortened escape latency and increased the frequency of crossing the platform in the Morris water maze test. T2-weighted imaging demonstrated that the MICD rat brain lesions were mainly located in the cortex and hippocampus, and injured volumes were reduced after EA. Furthermore, we found that these behavioral changes were concomitant with the deficit of the 5HT1A and PKA signaling pathways in the hippocampus, as the activation of the 5-HT1A receptor, the reduction of PKA kinase activity, and AMPA and NMDA receptor phosphorylation occurred in the injured hippocampus at Day 14 after MICD. Additionally, EA dramatically elevated the activation of PKA. Moreover, EA significantly increased intracellular calcium concentrations regulated by the activation of NMDA receptors. Therefore, PKA kinase and NMDA receptors mediated by 5-HT1A receptors in the hippocampus might contribute to improving learning and memory during the recovery process following ischemic stroke with an EA intervention.

State of rat colon microbiocenosis in chronic restraint stress treated with Selank

It is currently accepted that stress significantly affects composition of microbiocenosis due to changes in permeability of intestinal barrier and pro-inflammatory effects. This, in turn, changes behavioral reactions, anxiety and stress response. In this regard, it seems promising to use regulatory peptide-based neurotropic drugs including Selank to correct stress-induced dysbiosis. Our study was aimed at assessing state of rat colon microbiocenosis in modelled chronic restraint stress and treated with Selankby using 65 Wistar male rats divided into five groups (per 13 rats in each): group 1 — rats injected with saline; group 2 — injected with saline and induced chronic restraint stress; group 3–5 — administered with Selank at dose of 80 μg/kg, 250 μg/kg and 750 μg/kg body weight, respectively, and induced chronic restraint stress. Quantitative and qualitative study of animal colon microbiota was carried out according to the method by L.I. Kafarskaja and V.M. Korshunov. Identification of microorganisms was carried out by using a Maldi Biotyper Microflex mass spectrometer (Bruker, United States). Microbial species-specific composition was presented as lg CFU/g mass of examined sample. For each identified microbial genus, the relative mean and frequency of occurrence were calculated. Statistical significance of differences in mean values was determined by using Student’s t-test. Chronic restraint stress in the experiment did not result in affecting dominant microbiota species in rat colon nor reduce their frequency, however, it significantly influenced examined parameters for commensal microbiota disturbing pattern of pathogenic bacterial strains. Use of Selank led to the reversing changes in composition of colonic microbiocenosis caused by stress model. Moreover, magnitude of parameters examined in experiment after applying Selank at dose of 750 μg/kg reached those in non-stressed animals. Thus, effects related to Selank administration may presumably be mediated due to both central and peripheral effects including immunotropic and anti-inflammatory activities which contributed to restoring colon microbiocenosis composition in stress model.

Exercise effects on brain and behavior in healthy mice, Alzheimer's disease and Parkinson's disease model-A systematic review and meta-analysis

This systematic review and meta-analysis examines how exercise modifies brain and behavior in healthy mice, dementia (D) and Parkinson disease (PD) models. A search was performed on the Medline and Scopus electronic databases (2008-2019). Search terms were "mice", "brain", "treadmill", "exercise", "physical exercise". In the total, 430 were found but only 103 were included. Animals n = 1,172; exercised 4-8 weeks (Range 24 h to 32 weeks), 60 min/day (Range 8-120 min per day), and 10/12 m/min (Range 0.2 m/min to 36 m/min). Hippocampus, cerebral cortex, striatum and whole brain were more frequently investigated. Exercise improved learning and memory. Meta-analysis showed that exercise increased: cerebral BDNF in health (n = 150; z = 5.8, CI 3.43-12.05; p < 0.001 I2 = 94.3 %), D (n = 124; z = 4.18, CI = 2.22-9.12; p < 0.001; I2 = 93.7 %) and PD (n = 16 z = 4.26, CI 5.03-48.73 p < 0.001 I2 = 94.8 %). TrkB improved in health (n = 84 z = 5.49, CI 3.8-17.73 p < 0.001, I2 = 0.000) and PD (n = 22; z = 3.1, CI = 2.58-67.3, p < 0.002 I2 = 93.8 %). Neurogenesis increased in health (n = 68; z = 7.08, CI 5.65-21.25 p < 0.001; I2 17.58) and D model (n = 116; z = 4.18, CI 2.22-9.12 p < 0.001 I2 93.7 %). Exercise augmented amyloid clearance (n = 166; z = 7.51 CI = 4.86-14.85, p < 0.001 I2 = 58.72) and reduced amyloid plaques in D models (n = 49; z = 4.65, CI = 3.94-15.3 p < 0.001 I2 = 0.000). In conclusion, exercise improved brain and behavior, neurogenesis in healthy and dementia models, reduced toxicity and cerebral amyloid. Evidence regarding inflammation, oxidative stress and energy metabolism were scarce. Studies examining acute vs chronic exercise, extreme training and the durability of exercise benefit were rare. Vascular or glucose metabolism changes were seldom reported.

Antidepressive Effects of Kamishoyosan through 5-HT1AReceptor and PKA-CREB-BDNF Signaling in the Hippocampus in Postmenopausal Depression-Model Mice

Females are well known to suffer disproportionately more than males from stress-related neuropsychiatric disorders, especially during perimenopausal and postmenopausal periods. In addition to a decline in serum estradiol levels, environmental stress and social stress likely contribute to the development of neuropsychiatric symptoms in perimenopausal and postmenopausal women. Kamishoyosan (KSS) is a traditional Japanese Kampo medicine, composed of a specified mixture of 10 crude compounds derived from plant sources, widely used for various neuropsychiatric symptoms in perimenopausal and postmenopausal women. However, the molecular mechanisms underlying KSS-mediated attenuation of neuropsychological symptoms and stress-response behaviors in perimenopausal and postmenopausal women remain unknown. In the present study, we first established a mouse model for postmenopausal depression-like signs using chronic water-immersion and restraint-stressed ovariectomized (OVX) mice to investigate the underlying molecular mechanism of KSS. We found that continuous administration of KSS to these mice normalized the activation of the hypothalamic-pituitary-adrenal (HPA) axis, ameliorated stress-induced depressive behavior, and prevented a decrease of neurogenesis in the hippocampus. As previous studies have implicated dysfunction of the hippocampal 5-HT1A receptor (5-HT1AR) in depressive disorders, we also evaluated the effect of KSS on 5-HT1AR expression and the protein kinase A- (PKA-) cAMP response element-binding- (CREB-) brain-derived neurotrophic factor (BDNF) signaling pathway in the hippocampus in this model. The level of 5-HT1AR in the hippocampus decreased in chronic stress-exposed OVX mice, while KSS treatment normalized the stress-induced decrease in 5-HT1AR expression in the hippocampus of chronic stress-exposed OVX mice. Furthermore, we found that KSS treatment upregulated the expression levels of phosphorylated PKA (p-PKA), phosphorylated CREB (p-CREB), and BDNF in the hippocampus in chronic stress-exposed OVX mice. These results suggest that KSS improves neuropsychiatric symptoms through 5-HT1AR and PKA-CREB-BDNF signaling in the hippocampus in postmenopausal women.

Hippocampal proteomic changes of susceptibility and resilience to depression or anxiety in a rat model of chronic mild stress

Chronic stressful occurrences are documented as a vital cause of both depression and anxiety disorders. However, the stress-induced molecular mechanisms underlying the common and distinct pathophysiology of these disorders remains largely unclear. We utilized a chronic mild stress (CMS) rat model to differentiate and subgroup depression-susceptible, anxiety-susceptible, and insusceptible rats. The hippocampus was analyzed for differential proteomes by combining mass spectrometry and the isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique. Out of 2593 quantified proteins, 367 were aberrantly expressed. These hippocampal protein candidates might be associated with susceptibility to stress-induced depression or anxiety and stress resilience. They provide the potential protein systems involved in various metabolic pathways as novel investigative protein targets. Further, independent immunoblot analysis identified changes in Por, Idh2 and Esd; Glo1, G6pdx, Aldh2, and Dld; Dlat, Ogdhl, Anxal, Tpp2, and Sdha that were specifically associated to depression-susceptible, anxiety-susceptible, or insusceptible groups respectively, suggesting that identical CMS differently impacted the mitochondrial and metabolic processes in the hippocampus. Collectively, the observed alterations to protein abundance profiles of the hippocampus provided significant and novel insights into the stress regulation mechanism in a CMS rat model. This might serve as the molecular basis for further studies that would contributed to a better understanding of the similarities and differences in pathophysiologic mechanisms underlying stress-induced depression or anxiety, and stress resiliency.

SiNiSan Ameliorates the Depression-Like Behavior of Rats That Experienced Maternal Separation Through 5-HT1A Receptor/CREB/BDNF Pathway

Background: Early adverse life stress is an important dangerous factor in the development of psychiatric disorders, particularly depression. Available clinical antidepressant agents, such as fluoxetine, [a selective serotonin reuptake inhibitor (SSRI)], are unsatisfactory because of their side effects. SiNiSan (SNS) is a classic Chinese medicine prescription regarded to disperse stagnated liver qi to relieve qi stagnation. Therefore, this study was designed to detect the effects and molecular mechanism of SNS treatment in rats subjected to maternal separation (MS). Method: Male neonatal Wistar rats were divided into six groups including control + ddH₂O, MS + ddH₂O, MS + fluoxetine (5 g/kg), MS + SNS -low dose (2.5 g/kg), MS + SNS -medium dose (5 g/kg), MS + SNS -high dose (10 g/kg). The volume of drugs and ddH2O in each group are according to the weight of rats every day (10 mL/kg). Each group comprised 16 pups with 8 young and 8 adult pups. Except for the control group, all MS groups were separated from their mothers for 4 h/day from 9:00 to 13:00 during postnatal days (PNDs) 1 to 21. After MS, the six groups were intragastrically administered with ddH2O, fluoxetine, and different doses of SNS until PND 28 (for young pups) and PND 56 (for adult pups). The pups were weighed every day, and depression-like behavior was assessed by sucrose preference test, open field test, and forced swimming test. Serotonin 1A (5-HT1A) receptor, phosphorylated protein kinase A (p-PKA) substrate, cAMP response element-binding protein (CREB), p-CREB and brain-derived neurotrophic factor (BDNF) in the hippocampus were examined by Western blot, and in situ 5-HT1A receptor expression was measured by IHC. Results: Young and adult MS rats exhibited depression-like behavior. However, the depression-like behavior was ameliorated by SNS in both age groups. The levels of 5-HT1A receptor, p-CREB, and BDNF in the hippocampus were reduced in young and adult MS rats. SNS treatment significantly up-regulated the expression of 5-HT1A receptor, p-CREB, and BDNF in the hippocampus of adult MS rats. However, few significant effects on the protein expression were observed in the young MS rats. Conclusion: MS in infancy could develop depression-like behavior in young and adult. SNS treatment may perform antidepressant effects on young and adult MS rats through the BDNF/PKA/CREB pathway.

Absence of Stress Response in Dorsal Raphe Nucleus in Modulator of Apoptosis 1-Deficient Mice

Modulator of apoptosis 1 (MOAP-1) is a Bcl-2-associated X Protein (BAX)-associating protein that plays an important role in regulating apoptosis. It is highly enriched in the brain but its function in this organ remains unknown. Studies on BAX^-/- mice suggested that disruption of programmed cell death may lead to abnormal emotional states. We thus hypothesize that MOAP-1^-/- mice may also display stress-related behavioral differences and perhaps involved in stress responses in the brain and investigated if a depression-like trait exists in MOAP-1^-/- mice, and if so, whether it is age related, and how it relates to central serotonergic stress response in the dorsal raphe nucleus. Young MOAP-1^-/- mice exhibit depression-like behavior, in the form of increased immobility time when compared to age-matched wild-type mice in the forced swimming test, which is abolished by acute treatment of fluoxetine. This is supported by data from the tail suspension and sucrose preference tests. Repeated forced swimming stress causes an up-regulation of tryptophan hydroxylase 2 (TPH2) and a down-regulation of brain-derived neurotrophic factor (BDNF) in the dorsal raphe nucleus (DRN) in young wild-type (WT) control mice. In contrast, TPH2 up-regulation was not observed in aged WT mice. Interestingly, such a stress response appears absent in both young and aged MOAP-1^-/- mice. Aged MOAP-1^-/- and WT mice also have similar immobility times on the forced swimming test. These data suggest that MOAP-1 is required in the regulation of stress response in the DRN. Crosstalk between BDNF and 5-HT appears to play an important role in this stress response.

Treatment with Shuyu capsule increases 5-HT1AR level and activation of cAMP-PKA-CREB pathway in hippocampal neurons treated with serum from a rat model of depression

Depressive disorder (DD) is one of the typical affective disorders with a high morbidity, high suicide rate and high recurrence rate. Dysfunction of the 5-hydroxytryptamine 1A receptor (5-HT1AR) in the brain may serve an important role in the pathogenesis of DD. Currently, selective serotonin reuptake inhibitors are the first line antidepressants with 60–70% efficacy and severe adverse effects. Previous studies have demonstrated that Chinese herbal medicines, including the Shuyu capsule (SYC), are effective antidepressants with few side effects. However, the mechanism remains unclear. In the present study, the effects of the SYC on the 5-HT1AR level and the activation of adenylyl cyclase-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)-cAMP response element-binding (CREB) signaling pathway that 5-HT1AR mediates in the cells of hippocampal neurons were investigated in vitro. The SYC demonstrated an antidepressant effect similar to that of fluoxetine in a rat depression model. Treatment of hippocampal neurons with the serum of depressive rats resulted in a decrease in the 5-HT1AR protein level and the activation of the cAMP-PKA-CREB signaling pathway in hippocampal neurons. Exposure to the serum of rats that received chronic mild stress plus SYC treatment led to no alterations in the 5-HT1AR level or the activation of the cAMP-PKA-CREB signaling pathway compared with those of cells exposed to normal rat serum. This effect is similar to the effects of 5-HT1AR antagonist WAY-100635. In addition, the 5-HT1A agonist 8-hydroxy-(dipropylamino) tetralin did not antagonize the effects of the SYC. Furthermore, the SYC exhibited an increased effect compared with fluoxetine on 5-HT1AR levels and CREB activation. The present study suggested that the SYC functions by increasing 5-HT1AR protein levels and the activation of the 5-HT1AR-mediated cAMP-PKA-CREB signaling pathway in hippocampal neurons.

Coptidis Rhizoma Prevents Heat Stress-Induced Brain Damage and Cognitive Impairment in Mice

Heat stress conditions lead to neuroinflammation, neuronal death, and memory loss in animals. Coptidis Rhizoma (CR) exhibits potent fever-reducing effects and has been used as an important traditional medicinal herb for treating fever. However, to date, the effects of antipyretic CR on heat-induced brain damages have not been investigated. In this study, CR significantly reduced the elevation of ear and rectal temperatures after exposure to heat in mice. Additionally, CR attenuated hyperthermia-induced stress responses, such as release of cortisol into the blood, and upregulation of heat shock protein and c-Fos in the hypothalamus and hippocampus of mice. The administration of CR inhibited gliosis and neuronal loss induced by thermal stress in the hippocampal CA3 region. Treatment with CR also reduced the heat stress-induced expression of nuclear factor kappa β, tumor necrosis factor-α, and interleukin-1β (IL-1β) in the hippocampus. Moreover, CR significantly decreased proinflammatory mediators such as IL-9 and IL-13 in the heat-stressed hypothalamus. Furthermore, CR attenuated cognitive dysfunction triggered by thermal stress. These results indicate that CR protects the brain against heat stress-mediated brain damage via amelioration of hyperthermia and neuroinflammation in mice, suggesting that fever-reducing CR can attenuate thermal stress-induced neuropathology.

Prenatal noise stress impairs HPA axis and cognitive performance in mice

Noise stress is a common environmental pollutant whose adverse effect on offspring performance has been less studied. This study was novel in terms of using “noise” as a prenatal stress compared with physical stress to explore the effect of stress during gestation on HPA axis activation, cognitive performance, and motor coordination, as well as in investigating the effect of behavioral assessments on the corticosterone (CORT) levels. Three groups of C57BL/6 mice with a gestational history of either noise stress (NS), physical stress (PS), or no stress were examined in several behavioral tests. Plasma CORT level was significantly higher before starting the behavioral tests in NS group than the two other groups. It was significantly increased after the behavioral tests in both prenatal stressed groups relative to the controls. Stress caused anxiety-like behavior and reduced learning and memory performance in both stressed groups compared to the controls, as well as decreased motor coordination in the NS group relative to the other groups. The findings suggested that: prenatal NS severely changes the HPA axis; both prenatal stressors, and particularly NS, negatively impair the offspring’s cognitive and motor performance; and, they also cause a strong susceptibility to interpret environmental experiences as stressful conditions.

The Adverse Effects of Auditory Stress on Mouse Uterus Receptivity and Behaviour

Stress during gestation has harmful effects on pregnancy outcome and can lead to spontaneous abortion. Few studies, however, have addressed the impact of gestational stress, particularly auditory stress, on behavioural performance and pregnancy outcome in mice. This study aimed to examine the effect of two types of gestational stress on uterus receptivity and behavioural performance. Pregnant C57BL/6 mice were randomly assigned to either auditory or physical stress conditions or a control condition from gestational days 12-16. The auditory stress regimen used loud 3000 Hz tone, while the physical stressor consisted of restraint and exposure to an elevated platform. Three behavioural tests were performed in the dams after weaning. Uterine receptivity was investigated by counting the number of sites of implantation and fetal resorption. Also, the offspring survival rates during the early postnatal period were calculated. Auditory stress caused an increase in anxiety-like behaviour, reduced time spent exploring new object/environment, and reduced balance when compared to the physical stress and control groups. Auditory stress also caused higher rates of resorbed embryos and reduction of litter size. Our results suggest that the adverse effect of noise stress is stronger than physical stress for both uterus receptivity and behavioural performance of the dams.

SB203580 reverses memory deficits and depression-like behavior induced by microinjection of Aβ1-42 into hippocampus of mice

A high co-morbidity between Alzheimer's disease (AD) and depression suggests there might be similar mechanisms underlying the course of these diseases. Previous studies have shown that p38MAPK plays a critical role in the pathophysiology of AD and depression. However, little is known about whether SB203580, a selective inhibitor of p38MAPK, may protect against AD-associated cognitive impairments and depression-like behavior, simultaneously. Herein, we have shown, for the first time, that SB203580 may reverse memory impairments and depression-like behavior induced by hippocampal infusion of β-amyloid 1-42 (Aβ_1-42), as measured by novel object recognition, Morris water maze, tail-suspension and forced-swimming tests. In addition, phorbol 12-myristate 13-acetate (PMA), a PKC activator which also activates p38MAPK, significantly abolished the effects of SB203580. Moreover, Aβ_1-42 causes increased phosphorylation of p38MAPK and decreased phosphorylation of Ser9-glycogen synthase kinase 3β (GSK3β) and cAMP-response element binding protein (CREB) in the hippocampus of mice, which could be significantly reversed by SB203580. Our results suggest that SB203580 reversed Aβ_1-42-induced cognitive impairments and depression-like behavior via inhibiting p38MAPK signaling pathway, which not only supports p38MAPK as a therapeutic target for AD-associated cognitive dysfunction and depression-like behavior, but also provides experimental basis for the use of SB203580 in co-morbidity of AD and depression.

Alterations in splenic function and gene expression in mice with depressive-like behavior induced by exposure to corticosterone

Depressed patients present with increased cortisol levels and attenuated immune responses. However, little is known about the association between depression and the spleen, as this is the largest peripheral immune organ. In this study, we examined alterations in splenic function and gene expression in mice with depressive-like behavior, well as the expression of certain proteins in related pathways. A mouse model of depression was established with the use of corticosterone. Splenic function and histopathology were assessed using Wright and H&E staining. The Agilent Whole Mouse Genome Oligo Microarray containing >41,174 transcript probes was used to measure the levels of gene-expression in the spleens from control and model mice, and the levels of certain proteins associated with depression were measured by western blot analysis in the brain and spleen separately. We found that splenic function and immunity in the mice with depressive-like behavior were markedly impaired. A total of 53 genes exhibited a differential response in the mice with depressive-like behavior, 11 of which were more notable, including collagen, type VI, α5 (Col6a5), immunoglobulin superfamily, member 11 (Igsf11), D site albumin promoter binding protein (Dbp), tachykinin 2 (Tac2) and γ-aminobutyric acid B receptor 2 (Gabbr2). Pathway analysis revealed that the amino acid biosynthesis and the clock gene pathways were more meaningful among these genes. The levels of GABBR2, DBP and substance P (SP; encoded by the Tac2 gene) related proteins in the brain were markedly downregulated, and similar results were observed in the spleen. The anti-depressant, fluoxetine, reversed the changes in the levels of these proteins. The findings of our study regarding changes occurring in the spleen during depression may indirectly elucidate and shed light into the pathogenesis of depression and depressive-like behavior.

Inhibition of the cAMP/PKA/CREB Pathway Contributes to the Analgesic Effects of Electroacupuncture in the Anterior Cingulate Cortex in a Rat Pain Memory Model

Pain memory is considered as endopathic factor underlying stubborn chronic pain. Our previous study demonstrated that electroacupuncture (EA) can alleviate retrieval of pain memory. This study was designed to observe the different effects between EA and indomethacin (a kind of nonsteroid anti-inflammatory drugs, NSAIDs) in a rat pain memory model. To explore the critical role of protein kinase A (PKA) in pain memory, a PKA inhibitor was microinjected into anterior cingulate cortex (ACC) in model rats. We further investigated the roles of the cyclic adenosine monophosphate (cAMP), PKA, cAMP response element-binding protein (CREB), and cAMP/PKA/CREB pathway in pain memory to explore the potential molecular mechanism. The results showed that EA alleviates the retrieval of pain memory while indomethacin failed. Intra-ACC microinjection of a PKA inhibitor blocked the occurrence of pain memory. EA reduced the activation of cAMP, PKA, and CREB and the coexpression levels of cAMP/PKA and PKA/CREB in the ACC of pain memory model rats, but indomethacin failed. The present findings identified a critical role of PKA in ACC in retrieval of pain memory. We propose that the proper mechanism of EA on pain memory is possibly due to the partial inhibition of cAMP/PKA/CREB signaling pathway by EA.