Psychological Stress Group Research Articles

Effects of Different Stress Applications on Some Reproductive Hormones, Sperm Parameters, Lipid Profile, Immunohistochemical and Immunofluorescent Markers

The current study assessed how 5 stress protocols applied affected sperm parameters, lipid profile, and some reproductive hormones. Live materials of the study consisted of 50 rats. The number of rats in the groups was equal and they were randomly assigned. Each group consisted of 10 rats. No stress application was conducted in the control group. The rats in the psychological stress group were subjected to a cycle of 4-hour light and 20-hour dark per day. The rats in the physical stress group were deprived of feed and water for two hours per day. In the psychological stress + physical stress group, the psychological and physical stress protocol was conducted. In the first 4 groups, all the applications were conducted for 14 days. A different stress application was applied to the rats in the depression group every day. It was determined that the abnormal sperm rate was high in the stress and depression groups, but the highest rate was in the depression group. In addition, sperm motility and sperm concentration were the lowest in the depression group. While the stress and depression groups had significantly lower serum triglyceride and HDL levels and LH and FSH levels, cholesterol and LDL values were significantly higher. Bax expression and 8 OHdG expression were severe in psychological stress+physical stress group and depression group. When the findings are evaluated collectively; it was determined that stress negatively affected sperm parameters, lipid profile, reproductive hormones, immunofluorescence and immunohistochemical parameters.

Effects of self-perceived psychological stress on clinical symptoms, cortisol, and cortisol/ACTH ratio in patients with burning mouth syndrome

BackgroundPsychological stress is a crucial parameter in defining the symptoms of burning mouth syndrome (BMS). We hypothesized that the level of psychological stress in patients with BMS would correlate with severity of clinical symptoms, cortisol levels, and cortisol/ adrenocorticotropic hormone (ACTH) ratio. We aimed to comprehensively investigate the influence of clinical and hematologic parameters on the hypothalamic–pituitary–adrenal axis, particularly concerning the presence or absence of self-perceived psychological stress in patients with BMS. In addition, we aimed to identify parameters predicting psychological stress in these patients.MethodsOne hundred and forty-one patients with BMS (117 women, 82.98%; 56.21 ± 13.92 years) were divided into psychological stress (n = 68; 55 females, 56.39 ± 12.89 years) and non-psychological stress groups (n = 73; 62 females, 56.03 ± 14.90 years), and inter- and intra-group statistical analyses were conducted. Significant predictors of psychological stress in patients with BMS were investigated through multiple logistic regression analysis.ResultsThe prevalence of xerostomia was significantly higher (67.6% vs. 34.2%, p < 0.001), while unstimulated salivary flow rate was lower (0.66 ± 0.59 vs. 0.91 ± 0.53 mL/min, p < 0.01) in the psychological stress group than in the non-psychological stress group. SCL-90R subscale values for somatization, hostility, anxiety, and depression, as well as cortisol and ACTH levels and the cortisol/ACTH ratio, were also higher in the psychological stress group (all p < 0.05). Above-mean values for cortisol (AUC = 0.980, 95%CI: 0.959–1.000) and cortisol/ACTH (AUC = 0.779; 95%CI, 0.701–0.856) were excellent predictors of psychological stress, with cortisol (r = 0.831, p < 0.01) and cortisol/ACTH (r = 0.482, p < 0.01) demonstrating substantial correlations. Above-average values for cortisol (OR = 446.73) and cortisol/ACTH (OR = 6.159) significantly increased incidence of psychological stress in patients with BMS (all p < 0.001).ConclusionsAmong patients with BMS, xerostomia, decreased salivary flow rate, increased cortisol levels, and cortisol/ACTH ratio were associated with psychological stress, highlighting the psycho-neuro-endocrinological features of this condition. Cortisol and cortisol/ACTH ratio were strong predictors of psychological stress in patients with BMS.

Abstract 6474: Stress-related sick leave and subsequent cancer risk: A Swedish national register study of 516 678 cancer cases

Abstract Background: Despite previous studies investigating psychological stress in relation to cancer risk, no consensus has been reached as to whether stress is a modifiable risk factor for cancer. This study aims to investigate whether sick leave due to psychological stress can affect the risk of developing cancer. Method: This is a matched case-control study using Swedish nation-wide register data (study period 2005-2018). The main exposure is stress-related sick leave defined as registered sick leave due to psychological stress with the diagnosis codes of F43 (International Classification of Diseases codes: ICD) and its subclassifications and hereafter referred to as stress leave. For each primary cancer case (except non-melanoma skin cancer), up to five cancer-free controls were matched based on sex, age and county. Conditional logistic regression, conditioned on matching factors and adjusting for socioeconomic factors, was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs). For subgroup analyses by specific tumor sites, Bonferroni-corrected significance level of 0.002 (alpha value divided by the number of tumor sites = 0.05/24) was also applied. Results: The study comprised 516 678 cancer cases and 2 357 433 matched controls. Stress leave of any duration, was associated with a modestly increased risk of cancer, with the highest risk observed for 1-30 days of leave, vs no leave during follow-up (adjusted OR 1.05, 95% CI 1.02-1.09). In subgroup analyses by tumor sites, stress leave was associated with an increased risk of prostate cancer (adjusted OR for &amp;gt;90 days vs no stress leave 1.10, 95% CI 1.01-1.20) and cervix cancer (adjusted OR&amp;gt;90 days vs no leave 1.11, 95% CI 1.05-1.17). For lung cancer, an inverse risk relationship was found (adjusted OR&amp;gt;90 days vs no leave 0.88, 95% CI 0.77-0.99). For other tumor sites, associations were generally null or had wide confidence intervals. After applying a Bonferroni-corrected significance level, the association was still significant for cervical cancer. Further examination by sex, specific types of psychological stress and cancer groups based on established etiology (tobacco use, obesity, alcohol consumption and gastric hyperacidity) showed a clear exposure-response trend in men and pronounced associations for exhaustion disorder (ICD code: F43.8A) and tobacco-related cancers. In a post-hoc analysis, the association for other HPV-related cancers was similar to that for cervical cancer but not statistically significant. Conclusion: In this register study covering the entire Swedish population, we found that stress-related sick leave was associated with modestly higher risk of cancer, particularly the risk of cervical cancer. Potential higher risk of prostate cancer and lower risk of lung cancer were observed, though these associations were not statistically significant after controlling for multiple testing. Citation Format: Sai San Moon Lu, Jenny Hadrévi, Lisbeth Slunga Järvholm, Florentin Späth, Richard Palmqvist, Tommy Olsson, Sophia Harlid, Bethany van Guelpen. Stress-related sick leave and subsequent cancer risk: A Swedish national register study of 516 678 cancer cases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6474.

Trajectories of psychological stress in youth across the first year of inflammatory bowel disease diagnosis

ObjectiveYouth newly diagnosed with inflammatory bowel diseases (IBD) may be physically impacted by their disease and experience increased psychological stress. Stress is known to relate to greater reported IBD symptoms, but little is known about the longitudinal experience of stress and clinical symptoms of youth newly diagnosed with IBD. MethodsFifty-seven children (Mage = 14.26, range 8–17 years) diagnosed with IBD completed measures assessing psychological stress (PROMIS Psychological Stress Experiences), depressive symptoms (Children's Depression Inventory-2), and clinical disease symptoms (Self-Report Disease Activity) within 45 days of diagnosis and at 6-month and 1-year follow-ups. Group-based trajectory modeling was used to describe trajectory patterns of psychological stress over the first year of diagnosis and logistic regression identified predictors of group membership. ResultsTwo distinct groups of psychological stress trajectories were identified: 1) low prevalence over the first year of diagnosis (51%) and 2) moderate and increasing prevalence (49%). Membership in the moderate and increasing psychological stress group was associated with female sex and greater IBD symptoms at diagnosis. ConclusionFindings suggest roughly half of youth newly diagnosed with IBD would likely benefit from multidisciplinary assessment and intervention to promote adaptive stress management, given moderate and increasing stress levels. Future research is needed to evaluate specific intervention techniques most helpful to youth with IBD.

Chronic Psychological Stress Disrupts Iron Metabolism and Enhances Hepatic Mitochondrial Function in Mice.

To explore the changes in iron metabolism and mitochondrial function exposed to chronic psychological stress, seventy-five male mice aged 5 ~ 6weeks were randomly sorted into 2 groups: control group and chronic psychological stress group. Mice were conducted by communication box to induce psychological stress for 21 consecutive days. The results showed that chronic psychological stress led to a significant reduction in average daily gain (P < 0.01) and the final weight (P < 0.05). Chronic psychological stress greatly increased plasma and duodenal iron level (P < 0.05), whereas markedly decreased hepatic iron content in mice (P < 0.05). Increasing expression of duodenal DCYTB and FPN (P < 0.05) was observed in mice exposed to chronic psychological stress. Moreover, chronic psychological stress greatly enhanced hepatic TFR1, FTL, and FPN protein expression (P < 0.05) in mice. Additionally, chronic psychological stress enhanced the levels of hepatic NADH, NAD + , ATP, mtDNA content, mtDNA-encoded genes, and the activity of mitochondrial complex I and II (P < 0.05). Taken together, chronic psychological stress impairs growth, disrupts iron metabolism, and enhances hepatic mitochondrial function in mice. These results will provide new insights for understanding the mechanisms of iron metabolism and mitochondrial function during chronic psychological stress.

Aggravating Effects of Psychological Stress on Ligature-Induced Periodontitis via the Involvement of Local Oxidative Damage and NF-κB Activation.

Periodontitis is the leading cause of tooth loss in adults, and psychological factors play an important role in the development of periodontitis. To elucidate the adverse effects of psychological stress on the inflammatory process and redox status of periodontitis tissue, fifty male Sprague-Dawley rats were divided into the control, experimental periodontitis, psychological stress, experimental periodontitis plus psychological stress, and experimental periodontitis plus psychological stress plus fluoxetine groups. Chronic unpredictable mild stress (CUMS) was used to establish psychological stress, and silk ligature was used to induce experimental periodontitis. Four weeks later, stressed rats showed altered behaviour, serum hormone levels, and sucrose preference. More obvious alveolar bone loss and attachment loss and higher protein expressions of inflammatory cytokines were observed in the experimental periodontitis plus psychological stress group. The combination of CUMS and periodontitis had synergistic effects on increasing hypoxia-inducible factor-1α (HIF-1α) protein expression and reactive oxygen species (ROS) and malondialdehyde (MDA) contents and decreasing antioxidant enzyme activities compared with those in the stress or periodontitis groups. Moreover, psychological stress further increased p-IκBα and p-NF-κB p65 protein levels and decreased IκBα protein levels in periodontitis rats. Fluoxetine administration alleviated the adverse effects of psychological stress on the progression of periodontitis in rats. These results hint us that psychological stress could aggravate inflammation in periodontitis tissues, which may be partly due to local worsening of oxidative damage and further activation of the nuclear factor kappa-B (NF-κB) signalling pathway.

Effects of Psychological Stress on Central Dopaminergic Neurons

Objective — To evaluate the effects of psychological stress on central dopaminergic neurons. Methods — A test group of 90 rats was subjected to psychological stress for 30 minutes a day for 14 days. The rats were divided into three groups, and treated with tyrosine 250mg/kg, 500mg/kg, 1000mg/kg per day, 30 rats as psychological stress group and 30 rats as control group. After stress, TH and fos protein immunohistochemical staining were carried out on the relevant brain tissue sections of VTA (lateral tegmental area), Nac (nucleus accumbens) and mPFC (prefrontal cortex), and the results of TH immunohistochemical staining, Fos protein immunohistochemical staining and Fos/TH double staining were analyzed. Results — In VTA, the number of TH positive neurons in stress group was lower than that in control group (P<0.05), and the number of TH positive neurons in 500mg/kg and 1000mg/kg tyrosine groups was higher than that in stress group (P<0.05). The expression of Fos protein in VTA, mPFC and Nac of control group was lower than that of stress group, and the expression of Fos protein in VTA, mPFC and Nac of 500mg/kg and 1000mg/kg tyrosine groups was lower than that of stress group (P<0.05). Conclusion — Repeated psychological stress can damage central dopaminergic neurons, decrease the number of TH positive neurons and increase the expression of Fos protein. Tyrosine, the precursor of dopamine, can effectively control the damage.

Exacerbation of Urinary Storage Symptoms by the Psychological Stress Induced by the COVID-19 Pandemic.

This study aimed to determine whether psychological stress associated with the COVID-19 pandemic might exacerbate lower urinary tract symptoms (LUTS) and decrease lower urinary tract function in outpatients with LUTS. We evaluated 104 patients who visited our hospital during the first wave of the COVID-19 pandemic. Psychological stress was evaluated by the Stress Response Scale-18 (SRS-18). Subjects were divided into aggravation and non-aggravation of psychological stress groups according to the SRS-18. LUTS was evaluated according to the International Prostate Symptom Score (IPSS). Lower urinary tract function was evaluated as the post-void residual urine volume (PVR). Comparisons of scores and changes in scores of each parameter before versus during/after the first wave of the COVID-19 pandemic were performed between the two groups. Forty-two patients were included in each group. We observed no significant differences in the comparison of scores at each time point and in changes in total IPSS score, voiding symptom subscores and PVR between the two groups. Although no significant differences in storage symptom subscores were observed between the two groups, changes in storage symptom subscores increased significantly during the first wave of the pandemic in the aggravation of psychological stress group (p=0.02). However, no significant increase was observed after the first wave. Psychological stress during the COVID-19 pandemic might transiently aggravate storage symptoms in patients with LUTS. Physicians should be aware of the possibility of transient worsening of LUTS during future pandemics, and transiently additional medication might be effective in such patients.

Resveratrol ameliorates physical and psychological stress-induced depressive-like behavior.

Depression is a mental disorder that profoundly affects all aspects of life, but currently, antidepressants have some problems with their effectiveness and side effects. Resveratrol is a compound that has the ability to regulate the hypothalamic-pituitary-adrenal axis. This study aimed to determine resveratrol's effect on physical and psychological stress-induced depressive-like behavior. Mice were divided into control, physical stress, psychological stress groups. Treatment was conducted with fluvoxamine 20mg/kg and resveratrol 20, 40, and 80mg/kg for seven days. The depressive-like state was evaluated using a forced swim test (FST), tail suspension test (TST), and open field test (OFT). Physical stress and psychological stress induction increase the immobility time on FST and TST. Besides, there is an increase in time in central on OFT, which indicates an anxiety or mental illness-like behavior. However, the OFT examination on sniffing, rearing, grooming, and crossing behavior did not show a significant difference. Resveratrol 80mg/kg and fluvoxamine 20mg/kg were significantly reduced immobility time at TST compared to the physical stress group. While in psychological stress, resveratrol 80mg/kg tended to decrease immobility time but not significant. A significant increase in time in central duration was seen in the resveratrol 40mg/kg compared to the psychological stress. Stress induction causes increased amygdala corticotrophin-releasing factor (CRF) mRNA expression. However, neither resveratrol nor fluvoxamine affected amygdala CRF mRNA expression. Resveratrol ameliorates depressive-like behavior induced by physical and psychological stress.

The Effect of Exercise and Psychological Stress on Anti- and Proinflammatory Cytokines

Background/Aims: Research evidence regarding immune system responses and adaptations to psychological or physical stresses is controversial. This study aimed to investigate the effect of 8-week psychological stress and exercise activity (chronic adaptation) and the acute response of possibly adapted rats to psychological stress and exercise considering IFN-γ, IL-4, and IL-4/IFN-γ. Methods: Thirty-two rats were divided into 4 groups of 8 animals including control, exercise, psychological stress, and combination of exercise with psychological stress. IL-4 and IFN-γ cytokines were measured pre-experiment (preEX), immediately postexercise (IpostEX), and 72-h postexperiment protocol (72hpostEX). Results: There were no significant differences between the study groups regarding IFN-γ, IL-4, and IL-4/IFN-γ in preEX (p > 0.05), IpostEX (p > 0.05), and 72hpostEX (p > 0.05). However, IL-4 increased significantly in IpostEX compared with preEX in exercise (p = 0.012) and combination of exercise with psychological stress (p = 0.03) groups. Conclusions: Exercise and combination of exercise and psychological stress induce similar acute response to IL-4 in chronic trained and stressed rats. Also, exercise may induce an acute synergistic effect with psychological stress on IL-4.

Chronic Psychological Stress, but Not Chronic Pain Stress, Influences Sexual Motivation and Induces Testicular Autophagy in Male Rats.

Spermiogenesis is an important physiological process of mammalian fertilization. The germ cells are susceptible to the harmful effects of either psychological or physiological stress, which could induce male infertility. Our previous studies have found that chronic psychological stress could decrease sexual motivation. However, molecular mechanisms underlying male reproductive toxicity induced by chronic stress remain elusive. Recently, autophagy is proven to be involved in regulating the survival of germ cells, which is related to apoptosis. Herein, we established a chronic psychological stress model and a chronic pain model (physiological stressor) to explore the roles of autophagy in germ cells. Thirty-two male Sprague-Dawley rats were randomly divided into four groups, including the control group, the chronic psychological stress group, the SNI-sham group, and the chronic pain stress group. After exposure to stress for 35 days, open field test and the unconditioned sexual motivation test were performed. Following the behavioral experiment, autophagy in the rat testis was detected by Western blot and immunohistochemistry. We found both chronic psychological stress and chronic pain stress reduced total travel distance, the frequency of central crossing and increased the sensitivity to mechanical pain. While chronic psychological stress, but not the chronic pain stress declined sexual motivation. Chronic psychological stress prompt the expression of LC3-II with the decreased expression of p62, indicating that chronic psychological stress induced autophagy in rat testis. However, there was no significant difference between the expression of LC3-II and p62 in male rats under chronic pain stress. Therefore, chronic psychological stress and chronic pain stress have common behavior changes, but due to its unpredictability, chronic psychological stress leads to a decline in sexual motivation in male rats and induced the autophagy in testicular tissues.

The establishment of rat model in myocardial ischemia with psychological stress.

BackgroundPsychological stress can provoke and aggravate myocardial ischemia, and this stress can even trigger acute coronary syndromes or sudden cardiac death. Therefore, for the first time, this study aimed to investigate the method for establishing a rat model of myocardial ischemia with psychological stress and its evaluation.MethodsForty male Wistar rats were randomly divided into the sham (S, n=10), myocardial infarct (MI, n=10), psychological stress (MODEL, n=10), and myocardial infarct with psychological stress (MI + MODEL, n=10) groups. The rat model of psychological stress was established by measuring the data from activity restriction for 6 hours and followed by tail clamp stimulation for 5 minutes every day for 14 days. The rat model of the myocardial infarct with psychological stress was established by occluding the left coronary anterior descending artery in the MODEL rats. The body weight of rats was measured daily, the behavior parameters were evaluated via open-field test and elevated plus-maze, tongue color and sublingual vein were observed, rats’ acral blood flow perfusion was detected by PIM II (Perfusion Imager II), mesenteric microcirculation was measured by capillaroscopy, and hemodynamics was measured by a polygraph system. An automatic biochemical analyzer determined the content of serum cTnT (cardiac troponin T), Hcy (homocysteine), and activity of LDH (lactate dehydrogenase). Myocardial infarct size was measured with TTC (triphenyhetrazolium chloride) staining.ResultsWe found that rats in the psychological stress (MODEL) group were characterized by coarse hair, dark mucosa of the lips and claw, low spirit, decreased body weight, and increased anxiety. Compared with rats in the sham group, rats in the MODEL + MI group showed decreased mesenteric blood flow, narrowed arteriole and venule diameter, reduced acral blood flow perfusion, and LV ±dp/dtmax (the maximal rate of the increased and decrease of left ventricular pressure), as well as increased serum content of cTnT, Hcy, and LDH activity. Compared with the MI group, rats in the MODEL + MI group showed deteriorated microcirculation dysfunction manifested as a dark tongue color of deep purple, prominently extended and varicose sublingual vein, and aggravated myocardial damage in the form of increased infarct size and LDH leakage.ConclusionsIn conclusion, the rat model of myocardial ischemia with psychological stress was successfully established, and manifested as aggravating behavioral disorder, mesenteric microcirculation and left ventricular dysfunction, and myocardial damage.

Prevalence and risk factors associated with diabetes mellitus in local Population of Muzaffarpur, Bihar

Background: Nowadays Diabetes has become major problem in our society. There were over 72, 946, 400 cases of diabetes in India in 2017 and number is still arising. Different Risk factors associated with diabetes are-Positive family history, Tobacco and alcohol consumption, Hypertension, Psychological stress, stagnant life style, obesity etc. Aim: To find out the prevalence and association of various risk factors with diabetes mellitus in Muzaffarpur. Methods and material: The study consists of 600 people randomly selected from Muzaffarpur region. Demographic data of participants were collected with the help of glucometer, questionnaires and sphygmomanometer, Weighing machine and also statistical analysis was done. Statistical analysis: Chi-square and t-test was done. P value less than 0.05 was significant. Result: Overall prevalence of diabetes mellitus was found 5%. Male was more prone (6.35%) to diabetes than female (4.02%). Most of the subjects with diabetes (36.67%) belonged to the age group 41–50 years and maximum prevalence was seen in age group of 51–60 year (12.5%). Most significant risk factors were psychological stress (40%) followed by tobacco consumption (27%), positive family history (30%), Hypertension (24.24%) and obesity (23.53%). Diabetes Mellitus is more prone in those have these risk factors than those without risk factors. Persons with heavy physical activity were least prone (3.34%) to this disease. Conclusion: Main risk factor of diabetes mellitus is psychological stress and middle age male group were more prone to this disease. Improved lifestyle and awareness of risk factors can decrease prevalence of diabetes.

Psychological stress has a higher rate of developing addictive behaviors compared to physical stress in rat offspring.

Prenatal stress could have great influence on development of offspring and might alter cognitive function and other physiological processes of children. The current study was conducted to study the effect of physical or psychological prenatal stress on addictive and anxiety-like behavior of male and female offspring during their adolescence period (postnatal day (PND) 40). Adult female rats were exposed to physical (swimming) or psychological (observing another female rat swimming) stress from day six of gestation for 10 days. Male and female offspring were assayed for anxiety-like behavior, motor and balance function and morphine conditioned place preference using the open field, elevated plus maze (EPM), rotarod and wire grip assay and conditioned place preference. Offspring in both physical and psychological prenatal stress groups demonstrated significant increase in anxiety-like behavior in EPM paradigm, but no alterations were observed in motor and balance function of animals. Offspring in the psychological prenatal stress group had an increased preference for morphine in comparison to control and physical prenatal stress groups. Results of the current study demonstrated that animals exposed to psychological stress during fetal development are at a higher risk of developing addictive behaviors. Further research might elucidate the exact mechanisms involved to provide better preventive and therapeutic interventions.

Research Article: The effects of psychological and physical stressors on the secretion of immunoglobulin A in humans and mice

Stress generates multiple physiological effects through activation of neuroendocrine signaling. An increase in the hormone cortisol (or the analog corticosterone in some species), causes a significant decrease in circulating B-lymphocytes (the immune cells that produce antibodies), making the antibody immunoglobulin A (IgA) a good stress marker. The objective of these experiments was to examine IgA secretion after psychological and physical stressor treatments were applied. IgA was extracted from the salivary samples of college students who did or did not have a scheduled exam to test impacts of purely psychological stress, and from fecal samples of mice treated with human handling (psychological stress), forced exercise (physical stress), or a combination of the two. An enzyme-linked immunosorbent assay was used to measure IgA level in each sample. In humans, exam-taking was significantly associated with low salivary IgA levels (p 0.05), which may or may not have been a result of habituation to handling. However, both the physical stress group and combined physical and psychological stress group exhibited significantly reduced fecal IgA levels (p < 0.05) in comparison to the control. This study supports other findings that different stressors have different effects on physiological markers of stress, such as IgA level, and demonstrates those differences in humans and a controlled model of psychological and physical stressors in mice.

Acute physical and psychological stress effects on visceral hypersensitivity in male rat: role of central nucleus of the amygdala

ObjectiveThe aim of this study was to investigate the effects of acute physical and psychological stress and temporary central nucleus of the amygdala (CeA) block on stress-induced visceral hypersensitivity. MethodsForty two male Wistar rats were used in this study. Animals were divided into 7 groups (n=6); 1 – Control, 2 – physical stress, 3 – psychological stress, 4 – sham, 5 – lidocaine, 6 – lidocaine+physical stress and 7 – lidocaine+psychological stress. Stress induction was done using a communication box. ResultsAbdominal withdrawal reflex (AWR) score was monitored one hour after stress exposure. AWR score significantly heightened at 20, 40 and 60mmHg in the psychological stress group compared with control (p<0.05), while, it was almost unchanged in other groups. This score was strikingly decreased at 20, 40 and 60mmHg in lidocaine+psychological stress group compared with psychological stress with no tangible response on physical stress. Total stool weight was significantly increased in psychological stress group compared with control (0.72±0.15, 0.1±0.06g) (p<0.05), but it did not change in physical stress compared to control group (0.16±0.12, 0.1±0.06g) (p<0.05). Concomitant use of lidocaine with stress followed the same results in psychological groups (0.18±0.2, 0.72±0.15g) (p<0.05), while it did not have any effect on physical stress group (0.25±0.1, 0.16±0.12g) (p<0.05). ConclusionsPsychological stress could strongly affect visceral hypersensitivity. This effect is statistically comparable with physical stress. Temporary CeA block could also reduce visceral hypersensitivity post-acute psychological stress.

Experimental occlusal disharmony – A promoting factor for anxiety in rats under chronic psychological stress

Background and purposeClinically, patients under chronic psychological stress (PS) appear to be more susceptible to occlusal disharmony (OD) compared with those without PS. OD was proved to introduce anxiety-like stress. Therefore, the purpose of the study was to investigate whether OD would affect psychological stress-induced anxiety and its underlying mechanisms. MethodsChronic PS was induced by a communication box, and OD was produced by bonding a 0.3mm-thick crown on the right maxillary first molar of male Sprague-Dawley rats. Sixty-seven rats were randomly divided into 8 groups: (A) chronic PS plus OD group (n=6); (B) chronic PS plus sham OD group (n=6); (C) chronic PS only group (n=6); (D) OD group (n=6); (E) sham OD group (n=6); (F) control group (n=6); (G) naive group (n=6); (H) foot-shock group (n=25). Open-field test (OFT) and elevated plus maze test (EPM) were conducted on the 7th, 21th, 35th day to measure the anxiety level of each group except naive and foot-shock group. In addition, corticosterone (CORT) level in serum, 5-hydroxytryptamine (5-HT) and 5-HT2A receptor (5-HT2AR) expressions in prefrontal cortex (PFC), hippocampal CA1 and dentate gyrus (DG) areas were measured on the 35th day to elucidate the mechanism(s) by which the exacerbation occurred. ResultsThe significant differences in OFT and EPM tests on day 21 or day 35 between groups (p<0.01) indicated the successful establishment of animal model of PS or OD. And there was a significant increase in CORT concentration in serum (p<0.01), 5-HT expressions in PFC, hippocampal DG areas and 5-HT2AR expressions in PFC, hippocampal CA1 areas (p<0.05) in group A, B, C, D compared with group F. Similar results were also found in group A, B, C, D when compared with group G (p<0.05) except 5-HT expression in DG area in group C and D (p>0.05), together with a gradual decrease in values of all the parameters mentioned above from group A to group G. ConclusionThe significant changes in exploratory behaviors, serum CORT concentration, 5-HT and 5-HT2AR expressions induced by OD in rats with or without chronic PS, and more obvious alterations in rats with chronic PS, may indicate that OD may be a promoting factor for anxiety through both peripheral and central pathways via the hypothalamus-pituitary-adrenal (HPA) axis and 5-HT system.

Time-dependent co-relation of BDNF and CREB mRNAs in adult rat brains following acute psychological stress in the communication box paradigm

Psychological stress affects human health, and chronic stress leads to life-threatening diseases, such as depression and post-traumatic stress disorder. Psychological stress coping mechanisms involve the brain-derived neurotrophic factor (BDNF) and downstream cAMP response element binding protein (CREB), which are targets of the adverse effects of stress paradigms. Fourty-seven adult male Sprague-Dawley rats were divided into control, physical stress and six psychological stress groups which were assayed at 0h, 0.5h, 1h, 2h, 6h and 24h after communication box (CB) stress induction. Behavioral assessment using open field and elevated plus maze tests determined that CB stress significantly increased anxiety. After CB stress, the alternation of mRNA levels of BDNF and CREB were assessed at different time points by in situ hybridization. The mRNA levels of BDNF and CREB were significantly decreased, then gradually recovered over 24h to maximum levels in the hippocampus (CA1 region), prefrontal cortex (PFC), central amygdaloid nuclei (AG), shell of accumbens nucleus (NAC), periaqueductal gray (PAG) and ventral tegmental area, except for the ventral tegmental area (VTA). Moreover, mRNA levels of BDNF and CREB were positively correlated in all examined brain regions, except for the VTA region at 0 and 24h after CB stress induction. These findings suggest that BDNF and CREB may belong to the same pathway and be involved in psychological stress response mechanisms, and protect the organism from stress induced, aversive processes leading to disease.

Serotonin regulates brain-derived neurotrophic factor expression in select brain regions during acute psychological stress.

Previous studies suggest that serotonin (5-HT) might interact with brain-derived neurotrophic factor (BDNF) during the stress response. However, the relationship between 5-HT and BDNF expression under purely psychological stress is unclear. In this study, one hour before psychological stress exposure, the 5-HT1A receptor agonist 8-OH-DPAT or antagonist MDL73005, or the 5-HT2A receptor agonist DOI or antagonist ketanserin were administered to rats exposed to psychological stress. Immunohistochemistry and in situ hybridization revealed that after psychological stress, with the exception of the ventral tegmental area, BDNF protein and mRNA expression levels were higher in the 5-HT1A and the 5-HT2A receptor agonist groups compared with the solvent control no-stress or psychological stress group in the CA1 and CA3 of the hippocampus, prefrontal cortex, central amygdaloid nucleus, dorsomedial hypothalamic nucleus, dentate gyrus, shell of the nucleus accumbens and the midbrain periaqueductal gray. There was no significant difference between the two agonist groups. In contrast, after stress exposure, BDNF protein and mRNA expression levels were lower in the 5-HT1A and 5-HT2A receptor antagonist groups than in the solvent control non-stress group, with the exception of the ventral tegmental area. Our findings suggest that 5-HT regulates BDNF expression in a rat model of acute psychological stress.

반하후박탕(半夏厚朴湯)이 생쥐의 심리적 스트레스에 미치는 영향과 유전자 분석

Objectives: Banhahoobak-tang has been used to treat plum-pit qi, chest and hypochondriac dis-tension, moist or greasy tongue coat, and wiry slow or wiry slippery pulse. It might be used to control coughing and vomiting. We observed that Banhahoobak-tang extract (BHTe) had anti-psychological stress effect. The objective of this study was to determine the effect of BHTe on restoring the transcrip-tional regulation of genes related to psychological stress. Methods: After giving psychological stress to mice, BHTe was orally administered at 100 mg/kg/day for five days. After extracting whole brain tissue from the mice, the gene expression changes were de-termined by microarray. Transcription factor binding site (TFBS) analysis showed up- and down-regu-lated genes related to psychological stress were protected by BHTe and segregated according to the structure of TFBS. We performed text based Pubmed search to select significant target genes involved in psychological stress affected by BHTe.Results: 1. Serum corticosterone level was decreased in the BHTe administered group, although the psychological stress was increased. 2. The BHTe administered group had no significant change in nora-drenaline content in brain tissue, but the psychological stress group had decreased level. 3. The BHTe administered group had increased time of staying at open-arm than the psychological stress group. 4. Microarray revealed that TANK and RARA genes were up-regulated genes while AES, CDC42, FOS, NCL, and PVR were down-regulated genes by psychological stress but restored by BHTe.Key Words: Banhahoobak-tang extract (BHTe), Psychological stress, Anti-anxiety effect, Microarray.