Cold Immobilization Research Articles

Bi0-Reduced Graphene Oxide Composites for the Enhanced Capture and Cold Immobilization of Off-Gas Radioactive Iodine.

Radioactive waste management is critical for maintaining the sustainability of nuclear fuel cycles. In this study, we propose a novel bismuth-based reduced graphene oxide (Bi0-rGO) composite for the immobilization of off-gas radioactive iodine. This material synthesized via a solvothermal route exhibited a low surface area (2.96 m2/g) combined with a maximum iodine sorption capacity of 1228 ± 25 mg/g at 200 °C. The iodine sorbent was mixed with Bi2O3 powder and distilled water to fabricate waste matrices, which were cold-sintered at 300 °C under a uniaxial pressure of 500 MPa for 20 min to achieve a relative density of ∼98% and Vickers hardness of 1.3 ± 0.1 GPa. The utilized methodology reduced the iodine leaching rate by approximately 3 orders of magnitude through the formation of a chemically durable iodine-bearing waste form (BiOI). This study demonstrates the high potential of Bi0-rGO as an innovative solution for the immobilization of radioactive waste at relatively low temperatures.

Dual functional amorphous aluminosilicate sorbents for removing and cold-immobilizing cesium/cobalt/nickel-ions

Direct cold immobilization of the spent amorphous aluminosilicate adsorbent was achieved via a low-temperature sintering process at 200 °C without the addition of any binder or liquid agent for the first time. In this study, the amorphous aluminosilicates were synthesized as adsorbents for cesium/cobalt/nickel-ions and the measured maximum adsorption capacities of cesium, cobalt, and nickel-ions were 53.0, 18.8, and 21.2 mg/g, respectively. The cold-sintered as-spent aluminosilicate sorbent formed a dense monolith (density = 2.05 × 103 kg/m3 with a microhardness value of 3 ± 0.3 GPa). Pressure-induced consolidation of the amorphous phase and dehydration of the structurally bound water are attributed to the cold sintering mechanism. The normalized leaching rates through a 7-day product consistency test for cesium/cobalt/nickel-ions are 5.18 × 10−7, 6.27 × 10−6, and 3.25 × 10−6 g∙m−2∙d−1, respectively, much lower than crystalline aluminosilicates and other immobilization matrices. Furthermore, the measured leachability indices for all target ions and sodium, as per the American National Standards Institute/American Nuclear Society 16.1 (ANSI/ANS 16.1) for 90 days, are the highest value among other immobilization processes. To our best knowledge, the results present the first example of cold-immobilized used amorphous aluminosilicate sorbents, with a unique benefit of avoiding volatile radio-nuclides loss.

Experimental evaluation of Streblus asper hydroalcoholic extract for antistress activity

Stress is the causative factor for various diseases and disorders faced by the majority of the diseased population. The leaves of (S. ) are attributed to properties as per literature. The S. extract as tested for activity in animals. The study deals with the evaluation of S. extract for activity using cold immobilization stress. The S. extract (200 and 400 mg/kg) was administered to treatment groups 1 hour before stress methods for ten consecutive days. Induction of the stress procedure was repeated for ten days. Rats fasted overnight on 10th days, On 11th days the blood was collected from the retro-orbital vein for biochemical estimation under . Liver function profiles (SGOT, SGPT, and ALP), lipid profiles (TC, TG, HDL, LDL, and VLDL), differential leukocyte count (, eosinophils, lymphocyte, and ), and organs weight (adrenal gland, spleen, liver, and kidney) were evaluation parameters of activity in thecold immobilization stress. The dose group 400 mg/kg p.o.of S. extract for activity in cold immobilization showed significant variation (P< 0.1) when is compared with the stress control group. Therefore, it was revealed that S. extract showed potential activity.

Antioxidant, anticholinesterase and antifatigue effects of Trichilia catigua (catuaba)

BackgroundTrichilia catigua A. Juss. (Meliaceae) is a species known as catuaba and used in folk medicine for the treatment of fatigue, stress, impotence and memory deficit. The main phytochemical compounds identified in the barks of T. catigua are flavalignans, flavan-3-ols and flavonoids which are associated with its antioxidant activity. Pre-clinical studies with T. catigua extracts have identified many pharmacological properties, such as anti-inflammatory, antidepressant, antinociceptive, pro-memory and neuroprotective against ischemia and oxidative stress. This study was designed in order to compare the chemical composition and in vitro antioxidant and anticholinesterase activity of four different polarity extracts and selected the one most active for in vivo studies in rodent models of stress, fatigue and memory.MethodsHexane, chloroform, hydroalcoholic and aqueous extracts from bark of Trichilia catigua were analyzed by RPHPLC-DAD-ESI-MS/MS. Antioxidant activity was assessed by 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay and acetylcholinesterase inhibition by Ellman’s modified method. In vivo studies (stress, fatigue and memory) were carried out with adult male mice and rats treated with hydroalcoholic extract in doses of 25–300 mg/kg (p.o.).ResultsWe confirmed the presence of cinchonain IIa, Ia and Ib, as main constituents in the four extracts, while procyanidins were detected only in hydroalcoholic extract. Antioxidant and anticholinesterase activity were observed for all extracts, with most potent activity found on the hydroalcoholic extract (EC50 = 43 μg/mL and IC50 = 142 μg/mL for DPPH scavenger and acetylcholinesterase inhibition, respectively). The treatment of laboratory animals with hydroalcoholic extract did not protect rats from cold immobilization stress and did not prevent the scopolamine-induced amnesia in mice. However, the treatment of mice with the hydroalcoholic extract partially reduced the fatigue induced by treadmill, since the highest dose increased the spontaneous locomotor activity and reduced the deficit on grip strength after the forced exercise (p < 0.05), in some observation times.ConclusionsThese data suggest the hydroalcoholic extract as the most suitable for plant extraction and partially support the folk use of T. catigua as antifatigue drug.Graphical abstract.Trichilia catigua hydroalcoholic extract exhibits antioxidant and anticholinesterase activity in vitro and reduces the fatigue induced by forced exercise.

Cold immobilization stress induced brain neurotransmitter changes and effect of diosgenin from costus speciosus (KOEING) treatment in Wistar albino rats

Cold immobilization stress induced brain neurotransmitter changes and effect of diosgenin from costus speciosus (KOEING) treatment in Wistar albino rats

Experimental evaluation of Hygrophila Schulli seed extracts for antistress activity

Background: Stress is the causative factor for various diseases and disorders faced by majority of the diseased population. The seeds of Kokilākṣa Hygrophila schulli are attributed with Rasāyana properties as per the Ayurvedic literature. Considering the above, the seed extracts of H. schulli were screened for antistress activity in animals. Aim: To investigate the adaptogenic activity of ethanolic and hexane extracts of Hygrophila schulli seeds using in vivo models. Materials and Methods: The ethanolic and hexane extracts of Hygrophila schulli were subjected to qualitative chemical analysis to detect the presence of various phytoconstituents. The extracts were subjected HPLC analysis. The chromatographic analysis was carried out which revealed the multicomponent and complex nature of the extracts. The seed extracts of H. schulli were screened for antistress activity using Swim Endurance test in mice and Cold-Immobilization Stress model in rats to ascertain the Adaptogenic potential. Results: HPLC analysis confirmed the presence of flavonoid Quercetin, the ethanolic and hexane extracts were found to increase the swim endurance time, both extracts lowered the elevated blood glucose, cholesterol as well as triglyceride levels in cold immobilization stress model and maintained normal homeostasis. Conclusion: Hygrophila schulli enhances the physical endurance as well as normalizes the body imbalance due to stressors. The seeds of Hygrophila schulli thus possess adaptogenic property.

Lipidomic Modulation in Stressed Albino Rats Is Altered by Yolk and Albumen of Quail (Coturnix japonica) Egg and Poultry Feed.

Cold and immobilization stressors can generate oxidative stress as well as skeletal muscle fatigue. Free radicals cause oxidative degradation of lipids, proteins, nucleic acids, and carbohydrates molecules, thereby compromising cell integrity and function. Quail egg had been described as being very functional biochemically, due to the essential biomolecules it contains in very regulated quantity. This study was aimed for evaluating the dietary effect of the egg on lipid profile parameters on selected tissues. The antilipidemic properties of the egg yolk and albumen and poultry (layers) feed were determined in selected tissues in male albino rats assaulted with cold immobilization stress induced on them at 4°C for 2 hours, while diazepam was used as standard antistress drug. Antilipidemic activities were evaluated by lipid profile modulation (HDL, LDL, TRIG., and T-CHOL.). Quantitative and qualitative analyses of fatty acids profile of the yolk hexane-extract were determined by Gas Chromatography and Mass Spectrophotometry (GC-MS). The ameliorative impacts of diazepam (2.5 and 5.0 mg/mL/kg BW), yolk (5 and 10 mL/kg BW), albumen (5 and 10 mL/kg BW), and the feed (5–10 mg/kg BW) were competitively (p < 0.05) specific for each of the tissues. The result of the study suggested yolk and albumen of quail egg and poultry feed as antistress agents as well as lipid modulators.

The Effect of Long-Distance Transportation on the Fitness of Irradiated False Codling Moth (Lepidoptera: Tortricidae) for Use in a Sterile Insect Release Program.

The effect of cold immobilization and long-distance transport of irradiated Thaumatotibia leucotreta (Meyrick) on the flight ability of male (♂) and female (♀) moths, the longevity of male and female moths, and the realized fecundity of mating pairs CIM (chilled irradiated moths) ♀ × CIM♂, CIM♀ × NIP (nonirradiated pupae) ♂, NIP♀ × CIM♂, and NIP♀ × NIP♂ was examined to improve application of the sterile insect technique (SIT). Adult moths treated with 150 Gy of gamma radiation were immobilized with cold temperature between 4 and 6°C inside a polyurethane cooler box and transported for 12 h by road from Citrusdal, Western Cape Province, to Addo, Eastern Cape Province. Nonirradiated moths were transported as pupae inside a cardboard tray and removed by hand after which male and female pupae were separated and placed inside containers for eclosion. Male and female moths were individually placed inside petri dishes to determine longevity or paired with irradiated and nonirradiated counterparts to evaluate realized fecundity before incubation in 100% darkness at 25°C and 75% relative humidity. Flight tests were conducted indoors at 25°C by release of individual moths per hand. A significant decrease in flight ability and longevity of irradiated false codling moth was found after handling, cold immobilization, and transport, although critically, realized fecundity was not affected. Because of the impact of long-distance transport on quality of the released insects as well as the efficacy of SIT, comprehensive protocols for this critical step in the process need to be developed for a pestiferous insect with phytosanitary status such as false codling moth.

Absence of NF-κB subunit p50 ameliorates cold immobilization stress-induced gastric ulcers

Stress ulcers are a common complication in critically ill patients, but the underlying mechanism is little known. This study characterized the function of the p50 subunit of NF-κB in an experimental model of cold immobilization stress-induced gastric ulcers. Stress-induced gastric mucosal inflammation and gastric injury were examined in wild-type and NF-κB p50-deficient mice. When subjected to cold immobilization stress, NF-κB was rapidly activated in the gastric mucosa in WT mice whereas the majority of κB DNA-binding activity was abrogated from p50−/− mice. Deficiency of p50 ameliorated stress-induced expression of TNF-α, MIP-2, and ICAM-1, resulting in reduced mucosal accumulation of neutrophils and gastric injury. These data indicated a critical role for the p50 in the gastric mucosal inflammatory response to cold restraint stress.

Anethum graveolens Linn. (dill) extract enhances the mounting frequency and level of testicular tyrosine protein phosphorylation in rats

To investigate the effect of Anethum graveolens (AG) extracts on the mounting frequency, histology of testis and epididymis, and sperm physiology. Male rats induced by cold immobilization before treating with vehicle or AG extracts [50, 150, and 450 mg/kg body weight (BW)] via gastric tube for consecutive 1, 7, and 14 d were examined for mounting frequency, testicular phosphorylation level by immunoblotting, sperm concentration, sperm acrosome reaction, and histological structures of testis and epididymis, respectively. AG (50 mg/kg BW) significantly increased the mounting frequency on Days 1 and 7 compared to the control group. Additionally, rat testis treated with 50 mg/kg BW AG showed high levels of phosphorylated proteins as compared with the control group. In histological analyses, AG extract did not affect the sperm concentration, acrosome reaction, and histological structures of testis and epididymis. AG extract enhances the aphrodisiac activity and is not harmful to sperm and male reproductive organs.

Pharmacological evaluation of cytoprotective potential of Phyllanthus Emblica (PE) and Asparagus Racemosus (AR) in preventing gastric erosions, ulcerations and inflammation induced in rats

Background: Most of the currently available therapies for peptic ulcer disease have their own limitations and an ideal therapeutic agent is not yet available in the market.Hence,we decided to explore the cytoprotective potential of Indian Medicinal Plants namely Phyllanthus emblica and Asparagus racemosus along with ranitidine as a positive control in various animal models. Aims & Objective: To evaluate the cytoprotective effect of the extracts of Phyllanthus emblica (PE) and Asparagus racemosus (AR) in preventing gastric erosions, ulcerations and inflammation induced in rats. Materials and Methods: Cold immobilization stress, ethanol (99.9%), aspirin were the experimental models selected for inducing gastric erosions and ulcerations. Ulcer index , erosions, oedema, congestion and inflammation were the parameters studied for assessing gastric damage whereas carrageenininduced rat paw oedema model was used to induce inflammation. Ranitidine was used as a positive control. Results : The two drugs chosen for the study namely Phyllanthus emblica and Asparagus racemosus prevented gastric damage significantly in the ethanol group (p<0.05) and cold stress group (p<0.05). In the aspirin group, erosions, oedema, congestion and inflammation were remarkably reduced by PE cold water extract (PECWE) and PE hot water extract (PEHWE) and in the AR treated groups when compared with the control group. PECWE and PEHWE showed significant anti-inflammatory activity (p<0.05) comparable to aspirin thereby proving their role in inflammatory disorders. In our study, AR also showed a significant protection (p<0.05) against ethanol, cold stress and aspirin group. Conclusion : The present study supports that ethanol, cold simmobilization stress and aspirin induce gastritis, gastric erosions and ulcerations and Phyllanthus emblica and Asparagus racemosus have significant potential as prominent cytoprotectants against these toxic effects.

Possible protective effect of gum arabic on experimentally induced gastric ulcer in adult male albino rats

The Egyptian Journal of Histology 2011, 34:546–553 50 (1287 -2011) Background Peptic ulcer is a serious disease with a high incidence of occurrence in our community. Gum arabic (GA) is an edible, dried, gummy exudate from the stems and branches of Acacia senegal. It has been claimed to act as an antioxidant. Aim of the study The aim of this study was to evaluate the protective effect of GA on stress-induced peptic ulcer in rats. Material and methods In this study, 30 adult male rats were divided equally into three groups: the control group (group I), the stress ulcer group (group II), and the GA group (group III); the GA group received GA 7.5 g/kg/day through an orogastric tube for 10 days. After 10 days, the rats were fasted for 24 h. Cold immobilization stress was induced in groups II and III. The animals of all groups were then anesthetized with diethyl ether, and their stomachs were isolated immediately, opened from the greater curvature, and washed with saline. Ulcer severity, ulcer score, and ulcer index were determined. Stomach specimens were fixed in 10% neutral-buffered formalin for histological, hematoxylin and eosin, histochemical, Periodic Acid Schiff’s (PAS), and Masson’s trichrome stainings and for immunohistochemical detection of proliferating cell nuclear antigen (PCNA). Results Pretreatment with GA significantly decreased the gastric lesions. Both ulcer severity and score were significantly decreased (32.8% and 39.58%, respectively) compared with the stress-untreated group. Ulcer index was significantly decreased (49%) compared with the stress group (P < 0.05). The stress group showed atrophic gastric mucosa with loss of glandular tissue (hematoxylin and eosin), positive PAS reaction in the mucus neck cells, many collagen fibers between the atrophic glands, and moderate PCNA reaction in the glandular cells. In the GA group, there was nearly normal gastric mucosa with a small area of atrophied surface epithelium, PAS-positive reaction in surface and neck mucus cells, some collagen fibers between the near normal gastric glands, and mild PCNA reaction in the gland cells. Conclusion It can be concluded that GA exerts a protective effect against stress-induced gastric mucosal lesions in rats.

Effects of cold immobilization and recovery period on honeybee learning, memory, and responsiveness to sucrose

In addition to human error and variation in laboratory conditions, there are numerous factors that can complicate comparisons among studies. Furthermore, differences in how experimental methods are executed can make it difficult to distinguish between effects of focal versus extraneous variables. Insect neural function is commonly evaluated using Pavlovian conditioning techniques; learning and memory in many species can be assessed using the proboscis extension reflex (PER). However, there are significant inconsistencies in methods used to immobilize insects prior to PER tests. We compared responses of honeybees immobilized in a refrigerator, on ice, and in a freezer, and evaluated influence of recovery interval before testing. Ice-chilling weakly decreased learning (response to an originally neutral odor) more so than refrigeration or freezing, but not 24-h recall of odor. We found no significant differences in responsiveness to sucrose relative to cooling method, but responsiveness was significantly lower among honeybees left to recover for only 0.75 h versus 1.5 or 3 h. Finally, we observed increased responsiveness to sucrose and geraniol between June and August. Our results suggest that inconsistencies in cold immobilization methods could confound interpretation and comparison of results from a large body of work on honeybee learning and memory.

Effect of Pueraria tuberosa on Cold Immobilization Stress Induced Changes in Plasma Corticosterone and Brain Monoamines in Rats

The study was carried out to establish the anti-stress effect of Pueraria tuberosa in relation to the levels of plasma corticosterone and norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in whole brain and hypothalamus and compared with Withania somnifera (adaptogen). Adult male Wistar rats pretreated with 70% hydroethanolic extract of P. tuberosa tuber root (PTE) at the doses of 50, 100, 200 and 400 mg/kg, for 5 consecutive days. W. somnifera rhizome extract (WSE) at 100 mg/kg was used as reference drug. The rats were subjected to cold immobilization stress (IS) for 2 h. Thereafter, the animals were sacrificed and ulcer formation in gastric mucosa was noted. Weights of adrenals and spleens were also taken. Further, plasma corticosterone levels were estimated by spectrophotoflurometrically. Simultaneously, brain monoamines like, NE, DA and 5-HT were determined in whole brain and hypothalamus region HPLC electrochemical detector. IS for 2 h damaged the gastric mucosal layers, enhanced plasma corticosterone levels and increase adrenal glands and spleen weight. Further, IS elevated NE, DA and 5-HT levels both in whole brain and hypothalamus. PTE significantly protected the gastric mucosa, lowered corticosterone level in blood and negated the hypertrophy of adrenals and spleen. PTE (200 and 400 mg/kg) and WSE (100 mg/kg) significantly decreased IS elevated NE, DA and 5-HT both in whole brain and hypothalamus. These data suggest that anti-stress effect of Pueraria tuberosa may be modulated by monoaminergic system.

Activation of p38 MAPK by Reactive Oxygen Species Is Essential in a Rat Model of Stress-Induced Gastric Mucosal Injury

Stress ulceration is a common complication in critically ill patients and can result in significant upper gastrointestinal bleeding associated with a high morbidity and mortality. At present, little is known of the molecular mechanisms underlying the incidence of this type of gastric damage. In the present study, we investigated the temporal activation of the redox-sensitive p38 signaling transduction cascade and its roles in a well-defined experimental model of cold immobilization stress-induced gastric ulceration. Exposure of Sprague-Dawley rats to 6 h of cold immobilization stress led to a rapid activation of p38 in the gastric mucosa at as early as 15 min after stress, and this activation was maximal after 1.5 h of stress and still persisted until the end of stress. Selectively blocking p38 by pretreatment with SB 239063, a potent and selective p38 inhibitor, suppressed the stress-promoted TNF-alpha, IL-1beta, and CINC-1 production and then prevented the subsequent neutrophil infiltration, gastric mucosal epithelial necrosis and apoptosis, and the ulcerative lesions formation. Prior administration of the free radical scavengers, tempol and N-acetyl-L-cysteine, abolished the stress induction of p38 activation and the resulting mucosal inflammation and gastric injury. These results demonstrate that reactive oxygen species-mediated p38 activation plays an essential role in the pathogenesis of stress-induced gastric inflammatory damage in the rat model of cold immobilization stress. Our findings suggested that inhibition of p38 activation might be a potential strategy for the prophylaxis and treatment of stress ulceration.

Antidepressant and antistress activity of GC‐MS characterized lipophilic extracts of Ginkgo biloba leaves

Lipophilic extracts of Ginkgo biloba L. leaves were tested for their possible role on rodent models of depression and stress. Lipophilic extracts of Ginkgo leaves (LEG) at (50 and 100 mg/kg, p.o.) exhibited dose dependent, significant antidepressant activity in the behavioral despair test and learned helplessness rodent model of depression. The activities were comparable to that of imipramine (15 mg/kg) and EGb 761 (50 mg/kg). In the cold immobilization stress induced gastric ulcer model of stress, only the LEG showed a significant reduction in the ulcer index. GC-MS characterization of this bioactive extract was found to be rich in a group of 6-alkyl salicylates (6-AS), along with a fatty alcohol, fatty acids and cardanols. The n-heptadecenyl salicylate represented 60% of the 6-AS. Notable was the absence of dihydroxy alkylphenols which are linked to allergic reactions similar to the urushiols present in poison ivy. In commercial products of Ginkgo, these dihydroxy phenols as well as the favorable 6-AS are removed during enrichment of flavonol glycosides and terpenic lactones. The current findings suggest that intact carboxylic acid groups containing 6-AS are the bioactive components of the lipophilic extract of Ginkgo leaves with antidepressant and antistress activities.

Sustained activation of nuclear factor-κB by reactive oxygen species is involved in the pathogenesis of stress-induced gastric damage in rats

Stress ulceration is a common complication in critically ill patients, but the mechanisms involved are poorly understood. In this study we investigated the temporal activation of the redox-sensitive transcription factor nuclear factor-kappaB and its roles in an experimental model of cold immobilization stress-induced gastric mucosal lesions. Prospective, controlled, and randomized animal study. University research laboratory. Male Sprague-Dawley rats. The rats were subjected to cold immobilization stress for a total of 6 hrs. The temporal profiles of nuclear factor-kappaB activation and expression of tumor necrosis factor-alpha, interleukin-1beta, cytokine-induced neutrophil chemoattractant-1 (CINC-1), intercellular adhesion molecule-1 (ICAM-1), and inducible nitric oxide synthase (iNOS) were determined in the gastric corpus mucosa of stressed rats. To study the roles of nuclear factor-kappaB activation, rats received an intravenous bolus of a specific nuclear factor-kappaB inhibitor Bay 11-7082 (20 mg/kg) 1 hr before stress. For antioxidant administration, rats were treated with intravenous injection of a free radical scavenger pyrrolidine dithiocarbamate (50, 100, and 200 mg/kg) 1 hr before stress. Exposure of rats to 6 hrs of stress led to a rapid and persistent activation of nuclear factor-kappaB, which was associated with transient degradation of inhibitory protein IkappaBalpha and slower but sustained degradation of IkappaBbeta. Nuclear factor-kappaB activation preceded the induction of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs, all of which were linearly increased with the duration of stress. Bay 11-7082 selectively blocked the stress-induced nuclear factor-kappaB activation and up-regulation of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs. Inhibition of expression of these proinflammatory genes prevented the increases in myeloperoxidase activity (an indicator of neutrophil infiltration) in gastric mucosa and the development of gastric damage. Pyrrolidine dithiocarbamate dose-dependently inhibited the stress-induced nuclear factor-kappaB pathway activation and consequential proinflammatory gene expression, neutrophil infiltration, and gastric damage, suggesting the involvement of reactive oxygen species in these processes. Sustained activation of nuclear factor-kappaB by reactive oxygen species is an important in vivo mechanism mediating stress-induced gastric inflammatory damage in rats.

Evaluation of Baccharis trimera and Davilla rugosa in tests for adaptogen activity

Baccharis trimera (Asteraceae) and Davilla rugosa (Dilleniaceae) are used popularly as tonics, aphrodisiacs and for stomach ailments, among other uses. Hydroalcohol extracts of the aerial parts of both plants were investigated with regard to their chemical constitution and their pharmacological activity in tests that evaluate adaptogen activity. Alkaloids, flavonoids, saponins, polyphenols/tannins and coumarins were identified in both extracts, while lignans were found only in the extract of Davilla rugosa. This extract presented also a marked antioxidant activity and exerted a moderate antiulcer effect in rats submitted to cold immobilization stress. It did not, however, inhibit the increase in the levels of ACTH and corticosterone induced by stress. Moreover, the Davilla rugosa did not improve the physical performance of mice submitted to forced exercise and the learning time of old rats in the T-maze, neither did it reduce the blood viscosity of the old animals. Conversely, the Baccharis trimera extract only presented a moderate antioxidant activity, without any positive effect on the other tests. These results point to the absence of an adaptogen activity of Baccharis trimera, with some effects that could be related to such an activity as regards the Davilla rugosa.

Effect of variable moderate chronic stress on ligature‐induced periodontal disease in Wistar rats

The aim of this investigation was to study the impact of stress on ligature‐induced periodontal disease in rats by means of a variable moderate chronic stress model. Thirty male Wistar rats were randomly assigned to six groups. Control groups received only ligatures around the second maxillary molars, while experimental groups were exposed to stress in additional. Stress was imposed by means of flashing light, isolation, rat blood smelling, new environment exposure, immobilization in cold temperature and immobilization at room temperature. Stress was applied randomly, thereby diminishing adaptation of the animals to the model. The animals were killed after 29, 43, and 57 days. The distance between the cementum‐enamel junction and the alveolar bone (CEJ‐AB) was measured. Alveolar bone loss was statistically different between stressed and control animals, whereas differences were not observed between experimental periods. The mean CEJ‐AB distance in animals exposed to stress was 154.50 μm smaller than the corresponding distance in the controls. It might be concluded that variable moderate chronic stress decreased alveolar bone loss in a ligature‐induced periodontal disease model.

Blockade by N-methyl-D-aspartate of elevation of activator protein-1 binding after stress in rat adrenal gland.

Cold immobilization stress induced a marked elevation of expression of activator protein-1 (AP1) complex in rat hypothalamus, pituitary, adrenal, and gastric mucosa, but not in other discrete brain structures examined, when determined immediately after stress for 3 hr. Adrenal AP1 binding linearly increased with the duration of stress up to 6 hr, whereas the increase was seen in both adrenal cortex and medulla of rats stressed for 3 hr. In adrenals, the elevation exhibited decline profiles different from those of expression of cAMP response element binding protein. Western blotting revealed that stress for 3 hr induced significant increases in expression of the components of AP1 complex, c-Fos, c-Jun, and Jun-B proteins, in adrenals, without markedly affecting expression of Fos-B, Fra-2, and Jun-D proteins. The prior systemic administration of N-methyl-D-aspartate (NMDA) led to significant prevention of the elevation after stress for 3 hr in adrenals, whereas the NMDA antagonist dizocilpine alone induced a marked increase in adrenal AP1 binding, without altering the elevation by stress. These results suggest that stress may modulate de novo protein synthesis at the level of gene transcription by AP1 complex through a molecular mechanism associated with NMDA receptor channels in rat adrenal glands.