Animals ; Corticosterone ; blood ; Male ; Rats ; Rats, Wistar ; Stress, Physiological

AIMTo analyse the mechanism of corticosterone on the elevation of cytosolic free calcium ([Ca2+]i) induced by high-K+ in pheochromocytoma PC12 cells,

METHODSThe [Ca2+]i was real-time checked by fluorescence image system.

RESULTS(1) When the cells were preincubated at 37 degrees C for 5 min in the presence of various concentration corticosterone and stimulated with 55 mmol/L KCl , an inhibitory effect of corticosterone on delta[Ca2+]i was observed in a concentration-dependent manner. (2) When PC12 cells were preincubated with various concentration of B-BSA at 37 degrees C for 5 min and stimulated with 55 mmol/L KCl, an inhibitory effect of B-BSA on delta[Ca2+]i was observed, which is also concentration-dependent manner. (3) The inhibitory effect of corticosterone and B-BSA could not be antagonized by RU38486 at 10(-4) mol/L. (4) cycloheximide could not block the inhibitory effect of corticosterone after pretreating cells at 10(-5) mol/L at 37 degrees C for 3 hours.

CONCLUSIONIt is obvious that the locus of corticosterone action is on the plasmic membrane. The inhibitory effect of corticosterone is independent of protein synthesis and intracellular glucocorticoid receptor. The effect of corticosterone on [Ca2+]i is nongenomic action in PC12 cells.

Animals ; Calcium ; metabolism ; Corticosterone ; pharmacology ; PC12 Cells ; drug effects ; Potassium ; pharmacology ; Rats

We observed how the hypothyroid state affects diabetic states and modifies cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG). For this, 0.03% methimazole, an anti-thyroid drug, was administered to 7-week-old, pre-diabetic Zucker diabetic fatty (ZDF) rats by drinking water for 5 weeks, and the animals were sacrificed at 12 weeks of age. At this age, corticosterone levels were significantly increased in the ZDF rats compared to those in the control (Zucker lean control, ZLC) rats. Methimazole (methi) treatment in the ZDF rats (ZDF-methi rats) significantly decreased corticosterone levels and diabetes-induced hypertrophy of adrenal glands. In the DG, Ki67 (a marker for cell proliferation)- and doublecortin (DCX, a marker for neuronal progenitors)-immunoreactive cells were much lower in the ZDF rats than those in the ZLC rats. However, in ZDF-methi rats, numbers of Ki67- and DCX-immunoreactive cells were similar to those in the ZLC rats. These suggest that methi significantly reduces diabetes-induced hypertrophy of the adrenal gland and alleviates the diabetes-induced reduction of cell proliferation and neuronal progenitors in the DG.
Adrenal Glands ; Animals ; Cell Proliferation ; Corticosterone ; Dentate Gyrus ; Drinking Water ; Hypertrophy ; Hypothyroidism ; Methimazole ; Neurons ; Rats

The present study was aimed to investigate behavioural and biochemical effects of chronic exposure of amplitude modulated and non-modulated microwave radiation on laboratory mice. Chronic microwave exposures were executed with 2.45 GHz of either modulated (power density, 0.029 mW/cm²; specific absorption rate, 0.019 W/Kg with sinusoidal modulation of 400 Hz) or nonmodulated continuous sinusoidal wave (power density, 0.033 mW/cm²; specific absorption rate, 0.023 W/Kg) for 2 hrs daily for 1 month. Mice subjected to non-modulated microwave exposure had significantly increased acetylcholinesterase activity and increased intracellular calcium and nitric oxide levels in the cerebral cortex and hippocampus, and also had increased glucose and corticosterone levels in blood compared to control mice. These non-modulated microwave-exposed mice exhibited anxiety-like and depression-like behaviours. In contrast, mice exposed to modulated microwave for the same period did not show such changes in concomitant biochemical and behavioural analyses. These results suggest that chronic non-modulated microwave, but not modulated microwave, radiation may cause anxiety-like and depression-like behaviours and calcium- and NO-related biochemical changes in the brain.
Absorption ; Acetylcholinesterase ; Animals ; Anxiety ; Brain* ; Calcium ; Cerebral Cortex ; Corticosterone ; Depression ; Glucose ; Hippocampus ; Mice* ; Microwaves* ; Nitric Oxide

OBJECTIVE: Brain-derived neurotrophic factor (BDNF) and its specific receptor, tropomyosin-related kinase (TrkB), play important roles in treating depression. In this experiment, we examined whether 7,8-dihydroxyflavone, a novel potent TrkB agonist, could reverse the behavioral and biochemical abnormalities induced by the chronic mild stress (CMS) paradigm in rats. METHODS: SD rats were exposed to a battery of stressors for 56 days. 7,8-dihydroxyflavone (5 and 20 mg/kg) were administered intraperitoneally during the last 28 days of the CMS paradigm. Rats were tested in sucrose consumption test (SCT), forced-swimming test (FST) and elevated T-maze (ETM). Serum corticosterone levels and hippocampal BDNF levels of the rats were measured. RESULTS: Four-week CMS on the rats induced their depression-like behavior in SCT. The CMS-reduced sucrose consumption was reversed starting from 7 days after the 7,8-dihydroxyflavone (20 mg/kg) treatment and remained across the subsequent treatment regime. 7,8-dihydroxyflavone, when given at 5 mg/kg for 3 weeks, reduced the immobility time in the FST in the CMS-subjected rats. Additionally, the 4-week treatment with 7,8-dihydroxyflavone (20 mg/kg) attenuated the CMS-induced increase in anxiety-like behavior in the ETM. For the CMS-subjected rats, 7,8-dihydroxyflavone treatment dose-dependently reduced their serum corticosterone levels but increased their hippocampal BDNF levels only at 5 mg/kg. CONCLUSION: 7,8-dihydroxyflavone was beneficial for both depression and anxiety-like behaviors, and may exert fast-onset antidepressant effects. This provides a new insight into the pharmacological management of depression.
Animals ; Anxiety ; Brain-Derived Neurotrophic Factor ; Corticosterone ; Depression ; Phosphotransferases ; Rats* ; Sucrose

Animals ; Chronic Disease ; Corticosterone ; blood ; Hypoxia ; blood ; Male ; Rats ; Rats, Sprague-Dawley ; Testis ; metabolism ; Testosterone ; blood

Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 microg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level.
Animals ; Blood Glucose* ; Brain ; Corticosterone ; Glipizide ; Glyburide ; Immobilization* ; Insulin ; Mice ; Mice, Inbred ICR ; Plasma ; Tolazamide

Objective: A gradient stress model of PC12 cells induced by corticosterone was established to provide a basis for the evaluation and regulation of cell stress. Methods: The effect of corticosterone on cell viability was observed by measuring PC12 cell viability at different concentrations of corticosterone (0~1 000 μmol/L) after different intervention times (8~48 h) to screen the cell models for optimal intervention conditions. Key stress indicators (MDA, SOD, NADH, LDH) were measured spectrophotometrically and microscopically to evaluate the models. Results: When the concentration of corticosterone was below 200 μmol/L and the intervention time was 12 h, the cell viability was below half inactivation rate, which could reduce the confounding factors due to the decrease of cell viability in each group. Compared with the blank control group, corticosterone increased the levels of MDA, NADH and LDH,and decreased the levels of SOD in the model group in a concentration-dependent manner (P＜0.01), which was consistent with the construction of the gradient stress model. Conclusion: A gradient stress injury model of PC12 cells was successfully established, with intervention concentrations of 0 μmol/L, 25 μmol/L, 50 μmol/L, 100 μmol/L, 150 μmol/L and 200 μmol/L corticosterone at an intervention time of 12 h. The degree of stress injury of the cell model was increased gradually, which could be used as a basis and object for conducting cell stress injury assessment and regulation experiments.
Animals ; Cell Survival ; Corticosterone/pharmacology* ; NAD/pharmacology* ; PC12 Cells ; Rats ; Superoxide Dismutase

OBJECTIVE: Although the protective effects of Momordica charantia L. (MC) extract on chemical-induced testicular damage have been studied, the preventive effects of MC extract on functional proteins in the epididymis under chronic stress have never been reported. This study investigated the protective effects of MC fruit extract on protein secretion, especially tyrosine-phosphorylated proteins, in the epididymis of rats exposed to chronic unpredictable stress (CUS). METHODS: Total phenolic compounds (TPC), total flavonoid compounds (TFC) and antioxidant capacities of MC extract were measured. Adult male rats were divided into 4 groups: control group, CUS group, and 2 groups of CUS that received different doses of MC extract (40 or 80 mg/kg). In treated groups, rats were given MC daily, followed by induction of CUS (1 stressor was randomly applied from a battery of 9 potential stressors) for 60 consecutive days. Plasma corticosterone and testosterone levels were analyzed after the end of experiment. Expressions of heat-shock protein 70 (HSP-70) and tyrosine-phosphorylated proteins present in the fluid of the head and tail of the epididymis were quantified using Western blot. RESULTS: MC extract contained TPC of (19.005 ± 0.270) mg gallic acid equivalents and TFC of (0.306 ± 0.012) mg catechin equivalents per gram, and had 2,2-diphenyl-1-picrylhydrazyl antioxidant capacity of (4.985 ± 0.086) mg trolox equivalents per gram, radical 50% inhibitory concentration of (2.011 ± 0.008) mg/mL and ferric reducing antioxidant power of (23.697 ± 0.819) µmol Fe(II) per gram. Testosterone level in the epididymis was significantly increased, while the corticosterone level was significantly improved in groups treated with MC extract, compared to the CUS animals. Particularly, an 80 mg/kg dose of MC extract prevented the impairments of HSP-70 and tyrosine-phosphorylated protein expressions in the luminal fluid of the epididymis of CUS rats. CONCLUSION MC fruit extract had antioxidant activities and improved the functional proteins secreted from the head and tail of the epididymis. It is possible to develop the MC fruit extract as a male fertility supplement for enhancing functional sperm maturation in stressed men.
Male ; Rats ; Animals ; Antioxidants/pharmacology* ; Tyrosine/metabolism* ; Plant Extracts/therapeutic use* ; Corticosterone ; Seeds ; Testosterone ; Fruit/metabolism*

Objective: To understand the improvement effect of Lycium barbarum polysaccharide (LBP) on the intestinal flora of mother mice during pregnancy and their offspring who experienced chronic stress, and provide new ideas for improving the effect of stress on the intestinal tract. Methods: From July to October 2019, 24 SPF-grade female SD rats were selected and divided into control group, stress group, and stress+LBP group, with 8 rats in each group. A chronic unpredictable mild stimulation model during pregnancy was established (21 days) , and 40 mg/kg LBP solution was administered by gavage on the 8th day of stress. Venous blood from the medial canthus of the female mice was collected on the 1st day before stress and on the 1st, 7th, 14th and 21st days, respectively. Cortisol was measured and corticosterone concentration was calculated. The fresh feces of famale mice after stress and 20-day postnatal offspring mice were collected, and Illumina Miseq sequencing technology, alpha diversity and community composition were used to analyze the diversity and structure of intestinal flora. Results: On the 7th and 14th days of stress, the plasma corticosterone concentration of female mice in the stress group and stress+LBP group was higher than that in the control group (P<0.05) . In the Alpha diversity of female mice, the Ace index of the stress group was lower than that of the control group (P<0.05) . The analysis of intestinal flora structure showed that at the species level, the proportions of Lachnospiraceae and Lactobacillus in the stress+LBP group were higher than those in the stress group and control group. At the order level, the proportion of Clostridiales in the stress+LBP group was higher than that in the stress group and lower than that in the control group, while the proportion of Lactobacillales was higher than that in the stress group and control group. In the Alpha diversity of the offspring group, the Shannon index, Ace index and Chao index of the stress+LBP offspring group were higher than those of the stress offspring group (P<0.05) . The proportion of Lactobacillus in the stress+LBP offspring group was higher than that in the control offspring group and stress offspring group, and the proportions of Lachnospiraceae and Ruminococcaceae in the stress+LBP offspring group were higher than those in the stress offspring group, the proportion of Bacteroidales in the stress+LBP offspring group was lower than that in the stress offspring group, and the proportion of Clostridiales in the stress+LBP offspring group was higher than that in the stress and control offspring groups. Conclusion: The intervention of LBP may improve the changes in the intestinal flora diversity, abundance and flora structure of mother mice and offspring caused by pregnancy stress, thereby maintaining the balance of intestinal flora.
Animals ; Corticosterone ; Drugs, Chinese Herbal/pharmacology* ; Female ; Gastrointestinal Microbiome ; Hydrocortisone ; Mice ; Pregnancy ; Rats ; Rats, Sprague-Dawley