Protective effects of L-arginine on Alzheimer's disease: Modulating hippocampal nitric oxide levels and memory deficits in aluminum chloride-induced rat model

There is evidence that high daily intake of aluminum (Al) is associated with an increased risk of dementia or cognitive decline. We injected L-arginine into the dorsal hippocampus (DH) of an AlCl3-induced Alzheimer's model and studied memory deficit, β-amyloid (βA) accumulation, neurodegeneration, and molecular changes. Male Wistar rats were cannulated unilaterally in the DH under a stereotaxic apparatus and a dose of AlCl3 (1-200 μg/rat) was injected into the CA1. After recovery, L-arginine and L-NAME (0.05-25 μg/rat) were injected into CA1 and animals were tested in novelty seeking task. One group received βA (2 μg/rat, intra CA1) as a reference group. Control groups received saline (1 μL/rat, intra-CA1) and galantamine (25 μg/rat, intra-CA1), respectively. Finally, rats were anesthetized and hippocampal tissues were isolated on ice. Levels of neuronal NO synthase (nNOS), β-secretase and soluble guanylyl cyclase (sGC) were measured by western blotting. βA formation and the number of CA1 neurons were assessed by Congo red and Nissl staining. NOS activation by NADPH-diaphorase (NADPH-d) was investigated. All data were analyzed using analysis of variance (ANOVA) at α = 0.05 level. Like βA, AlCl3 (25 μg/rat) caused accumulation of βA in the DH and increased stopping of the animal on the novel side (indicating a recall deficit). CA1 neurons decreased, and nNOS and β-secretase, but not sGC, showed a change consistent with Alzheimer's. However, prophylactic intervention of L-arginine at 3-9 μg/rat was protective, probably by nNOS stimulation in DH, as shown by NADPH-d assay. L-arginine may protect against Alzheimer's by increasing hippocampal NO levels.

Effect of Papaver rhoeas hydroalcoholic extract on blood corticosterone and psychosocial behaviors in the mice model of predator exposure-induced post-traumatic stress disorder

The function of hypothalamic-pituitary-adrenal (HPA) axis and psychosocial behaviors are affected in post-traumatic stress disorder (PTSD). Based on presence of several beneficial alkaloids in Papaver rhoeas (PR) plant, we assessed the effects of PR hydroalcoholic extract on blood corticosterone and psychosocial behaviors in the mice model of predator exposure-induced PTSD. Male NMARI mice were assigned into two main groups (control or PTSD) according to stress exposure (presence or absent of the predator). Each main group was divided into four subgroups according to treatment with the different doses of PR extract. Mice were treated intraperitoneally by PR extract at three different doses (1,5&10 mg/kg) 30 min before the beginning of test on days 1, 2&3. Corticosterone concentration determined in the blood samples on days 1, 3&21, and mice examined for the psychosocial behaviors on the third day. PTSD induction in mice by exposing to hungry predator increased blood corticosterone and changed the psychosocial and physiological behaviors. PR extract decreased blood corticosterone in PTSD mice on the third day as well as 21st day. Also, PR extract improved the psychosocial and physiological behaviors in PTSD mice. Moreover, PR extract increased blood corticosterone in control mice at a dose-response manner. PR extract is able to decrease blood corticosterone in PTSD condition and probably prevent the HPA hyperactivity in PTSD mice when exposed to the stress stimuli. Accordingly, decreased blood corticosterone by PR extract might be involved in improvement of the physiological and psychosocial behaviors in PTSD mice.

Perceived Stress and Cfognition Function Quantification in a Scary Video Game: An Electroencephalogram Features and Biochemical Measures

Introduction

Video games affect the stress system and cognitive abilities in different ways. Here, we evaluated electrophysiological and biochemical indicators of stress and assessed their effects on cognition and behavioral indexes after playing a scary video game.

Methods

Thirty volunteers were recruited into two groups as control and experimental. The saliva and blood samples were collected before and after intervention (watching/playing the scary game for control and experimental groups respectively). To measure cortisol and salivary alpha-amylase (sAA) levels, oxytocin (OT), and brain-derived neurotrophic factor (BDNF) plasma levels, dedicated ELISA kits were used. Electroencephalography recording was done before and after interventions for electroencephalogram (EEG)-based emotion and stress recognition. Then, the feature extraction (for mental stress, arousal, and valence) was done. Matrix laboratory (MATLAB) software, version 7.0.1 was used for processing EEG-acquired data. The repeated measures were applied to determine the intragroup significance level of difference.

Results

Scary gameplay increases mental stress (P<0.001) and arousal (P<0.001) features and decreases the valence (P<0.001) one. The salivary cortisol and alpha-amylase levels were significantly higher after the gameplay (P<0.001 for both). OT and BDNF plasma levels decreased after playing the scary game (P<0.05 for both).

Conclusion

We conclude that perceived stress considerably elevates among players of scary video games, which adversely affects the emotional and cognitive capabilities, possibly via the strength of synaptic connections, and dendritic thorn construction of the brain neurons among players.

Highlights

The mental stress level increases in players of scary video games.The salivary cortisol and alpha-amylase levels are significantly higher after the scary gameplay.Plasma levels of oxytocin and brain-derived neurotrophic factor decrease after the scary gameplay.The arousal and valence features increase in players of scary video game.Cognitive capabilities are adversely affected by the scary gameplay.

Plain Language Summary

Nowadays, video games have become an important part of human life at different ages. Therefore, assessing their effects (improving and/or damaging) on cognition and behavior is important for understanding how they affect the nervous system. The results of such studies can be used to design a variety of games in the future in a way that minimizes the harmful side effects of video games on human cognitive functions and maximizes their beneficial effects.

Changes in psychological and cognitive variables as well as cortisol levels in recovered Covid-19 patients: a longitudinal study

BACKGROUND

Decreased psychological and cognitive functioning is one of the complications of Covid-19 disease. We aimed to evaluate mental health, cognitive functioning, and salivary cortisol levels in Covid-19 patients with different disease severities in three 45-day intervals after recovery.

METHODS

258 Covid-19 patients were assigned into three groups based on their disease severity: 112 patients in mild group, 67 patients in moderate group and 79 patients in severe group. The participants underwent psychological evaluations (including Depression, Anxiety and Stress Scale questionnaire, Beck Depression Inventory, SpeilBerger State-Trait Anxiety Inventory, Pittsburgh Sleep Quality Inventory), cognitive assessments (The Paced Auditory Serial Addition Test) and salivary cortisol level evaluation in three 45-day periods. Non-parametric statistical methods were applied for psychological and cognitive indicators, while two-way mixed model ANOVA was used to evaluate the cortisol concentration in three replications.

RESULTS

The group of mild patients became more anxious and the group of moderate patients became more anxious and depressed. But all three groups of patients developed severe sleep disorders over time. For cognitive functioning, although the results showed a decrease in the correct response rate, a significant increase in the correct response rate was observed in all three groups in all three measurements. However, the response speed not only did not increase, but also decreased in severe group. Cortisol level had a markedly increasing trend in all three groups.

CONCLUSION

Improvement of cognitive functioning was in line with the increase in cortisol. Besides, the decrease in mental health had no effect on the cognitive functioning.

The Relationship between the Severity of the COVID-19 Disease, Temperament and Psychological Factors

Objective: The coronavirus (COVID-19) pandemic negatively affects public mental health around the world. Individuals' reactions to COVID-19 vary depending on their temperament, individual differences, and personality traits. Therefore, the current study is conducted to assess the association of demographical features, Persian temperament, and psychological characteristics with the severity of COVID-19. Method: An online survey was sent to COVID-19 patients to collect their demographic information, COVID-19 symptoms, and clinical data. The Depression, Anxiety and Stress Scale (DAAS-21) questionnaire, Beck Depression Inventory (BDI-II), Spiel Berger State-Trait Anxiety Inventory (STAI) , Pittsburgh Sleep Quality Inventory (PSQI), and Persian general and brain temperament Questionnaire were also completed by 258 participants (127 men and 131 women) 45 days after recovery from COVID-19. Non-parametric analysis was used for statistical analysis. Results: Results showed the significant relationship of demographic factors such as weight, age and gender with the severity of the COVID-19 (P < 0.05). Mean scores of brain temperament (warm/cold) in the severe group were significantly lower than the moderate and mild groups (P < 0.05). There was a significant increase in the dry/wet temperament of the brain in the severe and moderate groups compared to the mild group (P < 0.05). The results of DASS-21 showed a significantly higher anxiety in patients with severe COVID-19 compared with moderate and mild groups (P < 0.05). The severe group was found to be significantly different compared to moderate group in the results of BDI-II (P < 0.05). The result of STAI (state and trait) showed a significant difference between the severe group and the mild and moderate groups. The score of PSQI between the moderate and mild groups was significant (P < 0.05). Conclusion: These results indicate the relationship between demographic factors such as weight, age and gender, brain temperament, as well as some psychological factors such as sleep quality and anxiety with the severity of the COVID-19 disease.

Evaluation of Stress and Cognition Indicators in a Puzzle Game: Neuropsychological, Biochemical and Electrophysiological Approaches

Video games have significant and diverse effects on stress and cognitive systems based on the game style. The effect of this media on the central nervous system is significant because of its repetition. Nowadays, video games have become an important part of human life at different ages, and therefore, assessing their effects (good and bad) on stress factors, cognition, and behavior can be an important help in understanding the nature of these games and managing their impact on humans. Consequently, this study aimed to investigate the effect of a puzzle game on the player's stress and cognitive indicators in neuropsychological, biochemical, and electrophysiological approaches. A total of 44 participants were entered into the study and randomly assigned to control and experimental groups. Our interventions were watching (control group) and playing (experimental group) the game. Salivary biomarkers (cortisol and alpha-amylase) were measured using the enzyme-linked immunosorbent assay method. Electrophysiological assessment of attention and stress was performed using electroencephalography. Neuropsychological assessments for the evaluation of mental health, mental fatigue, sustained attention, and reaction time were conducted using paced auditory serial addition test. All tests were administered before and after the interventions. The findings revealed that the salivary cortisol and alpha-amylase significantly reduced after playing the game. There were significantly higher levels of attention after playing the game. Mental health and sustained attention significantly increased after game playing. It can conclude that puzzle-style computer games can strengthen and empower the perceptual-cognitive system and suppress the stress system of players. Therefore, they can be used purposefully as a positive cognitive therapy approach.

Neurological Complications of Corona Virus: A Mini-Review

Following the outbreak of COVID-19 disease, which is caused by the coronavirus, there were reports of neurological complications, indicating that virus infection may have risks involving the nervous system. Stroke, encephalopathy, moderate to severe headaches, anosmia and dysgeusia, hallucination, and depression were the most neurological complications reported. The most important neurological complication of COVID-19 is anosmia, which is caused by the infection of the olfactory support cells. Hallucination and depression have been observed in those admitted to the intensive care unit, which is primarily related to general inflammatory reactions. Although brain autopsies of people who have died because of COVID-19 have shown that the virus can be detected in brain tissue. Studies indicate that viral infection has only been detected in the vascular part of the blood-brain-barrier. Perhaps the most critical finding of coronavirus infection in the brain is the activation of astrocytes and microglia in patients with COVID-19, which dilates the cerebral arteries in the brainstem, allows killer T cells to enter brain tissue, and causes cytotoxic effects in this part of the brain. This review focused on the neurological complications associated with COVID-19 and the possible mechanisms underlying these complications.

Improvement of Cognitive Indicators in Male Monkeys Exposed to Extremely Low-Frequency Electromagnetic Fields

Today, the production of extremely low-frequency electromagnetic fields (ELF-EMFs) has significantly increased. This study aimed to investigate the effect of the ELF-EMFs on the structure and function of the brain in male rhesus monkeys in terms of visual learning (VL), visual memory (VM), and visual working memory (VWM). To conduct the study, four monkeys were selected, of whom two monkeys were irradiated by 12-Hz ELF-EMFs with a magnitude of 0.7 microtesla, and two monkeys were tested without irradiation (control group). A blood sample was taken in three stages, namely pre- and post-irradiated and the recovery phases. Changes in the plasma levels of sodium, potassium, and adrenocorticotropic hormone (ACTH) were evaluated. Moreover, gene expression of N-methyl-D-aspartate (NMDA) receptors was assessed. The anatomical change of the brain's prefrontal area was measured by magnetic resonance imaging and Digital Imaging and Communications in Medicine LiteBox file. The abilities of VL, VM, and VWM significantly improved after the irradiation. Furthermore, the expression of the NMDA receptors gene and the plasma levels of sodium, potassium, and ACTH significantly enhanced after the irradiation. However, the prefrontal area was not significantly affected by the irradiation. No significant differences were observed in any of the studied factors in the control group. Our findings suggested that ELF-EMFs irradiation at 12 Hz positively affected VL and VWM. Consequently, 12-Hz ELF-EMFs irradiations can be widely applied to improve cognitive abilities in monkeys.

The Effect of 12 Hz Extremely Low-frequency Electromagnetic Field on Visual Memory of Male Macaque Monkeys

Introduction

Today, humans live in a world surrounded by electromagnetic fields. Numerous studies have been conducted to discover the biological, physiological, and behavioral effects of electromagnetic fields on humans and animals. Given the biological similarities between monkeys and humans, The present research aimed to examine Visual Memory (VM), hormonal, genomic, and anatomic changes, in the male rhesus macaques exposed to an Extremely Low-Frequency Magnetic Field (ELF-MF).

Methods

Four male rhesus macaques (Macaca mulatta) were used. For the behavioral tests, the animals should be fasting for 17 hours. For the tests such as visual memory, the animal's cooperation was necessary. Using the radiation protocol, we exposed two monkeys to a 12-Hz electromagnetic field with a magnitude of 0.7 μT (electromagnetic radiation) four hours a day for a month. Before and after the exposure, a visual memory test was conducted using a coated device (visible reward) on a movable stand. Ten milliliters of blood was obtained from the femoral artery of each monkey, and half of it was used to examine cortisol serum levels using the MyBioSource kit (made in the USA). The other half of the blood was used to extract lymphocytes for assaying expressions of Glucocorticoid Receptor (GR) genes before and after radiation using the PCR method. Anatomic studies of the amygdala were carried out based on pre- and post-radiation Magnetic Resonance Imaging (MRI).

Results

Research results indicated that visual memory in male primates increased significantly after exposure to the 12-Hz frequency. Hormonal analysis at the 12-Hz frequency showed a decrease in cortisol serum levels. However, visual memory and serum cortisol levels did not change considerably in male primates in the control group. There was no considerable amygdala volumetric difference after exposure to the 12-Hz frequency. The expression of the GR genes decreased in the 12-Hz group compared to the control group.

Conclusion

In short, these results indicated that ELF might benefit memory enhancement because exposure to the 12-HZ ELF can enhance visual memory. This outcome may be due to a decrease in plasma cortisol and or expression of GR genes. Moreover, direct amygdala involvement in this regard cannot be recommended.

Highlights

The effects of Extremely Low-Frequency Electromagnetic Fields (ELF-EMF) of 12 Hz on monkeys were studied.The results showed a reduction in the serum cortisol levels and the expression of GR genes.The amygdala anatomical area changes were not significant in the experimental group.In the experimental group, visual memory (delay of 30- and 60-s evaluation) improved after exposure to a frequency of 12 Hz.

Plain Language Summary

Extremely low-frequency electromagnetic fields are among the most important factors affecting humans. This study aimed to determine the fields of 12-Hz frequency on the visual memory changes of male monkeys. The importance of research is due to the cognitive similarity of monkeys to humans. The findings of the research can be attributed to humans. Behavioral, hormonal, genetic, and anatomical studies indicated improvement in visual memory (test monkeys versus control monkeys). This study demonstrates the effect of the 12-Hz frequency on the monkey's visual memory. Researchers can study 12-Hz frequency in other cognitive indices.

The Effect of Electrical Fields From High-voltage Transmission Line on Cognitive, Biological, and Anatomical Changes in Male Rhesus macaque Monkeys Using MRI: A Case Report Study

Introduction

Living near high-voltage power lines and exposure to high-frequency electromagnetic fields (EMFs) is a potentially serious hazard to animal and human health. The present study was conducted to evaluate the effect of high-frequency EMFs from simulated high-voltage electric towers on cognitive, anatomical, and biological changes in the male macaque.

Methods

In this study, two Rhesus macaque were recruited, one experimental and one control. The experimental subject was exposed to EMFs from 3 kV/m simulated electric towers with a specific protocol and the control subject was tested without irradiation (4h per day, for 30 days). All required tests were performed before and after the intervention on experimental and control monkeys. The anatomical alternation of the prefrontal area (PFA) was measured by MRI images. All tests were performed on irradiated and control animals before and after the intervention and the results were compared between irradiated and control animals.

Results

The results of the present study indicated increased white blood cell counts after high-frequency EMFs irradiation. Also, the red blood cell counts showed a decreasing trend after irradiation. The plasma adrenaline level increased after irradiation. Besides, the blood glucose levels increased after irradiation. The PFA was different before and after the irradiation. Moreover, some behavioral disorders, such as fatigue, drowsiness, anorexia, and insomnia were observed after irradiation.

Conclusion

The results of biological tests and MRI showed an elevated risk of immunodeficiency disorders, weakness, and behavioral disorders. People who live or work near high-voltage electric towers with high-frequency EMFs are warned.

Highlights

Magnetic, and electric fields from high pressure towers caused negative effects in terms of biology and even anatomical changes in the prefrontal part of the brain.Disturbance in the prefrontal part of the brain caused the monkey's cognitive and behavioral disorder.An increase in white blood cells, a decrease in red blood cells, and an increase in the adrenaline and blood sugar were indicative of biological disorders after wave exposure in male rhesus monkeys.The effects of magnetic and electric fields resulting from high pressure towers on the nerves and psyche require health researchers to do more studies.

Plain Language Summary

Today, one of the factors that threaten the cognitive and behavioral health of humans and animals is living in the vicinity of magnetic and electric fields resulting from the power transmission of high-pressure towers. These fields cause cognitive and behavioral disorders in living beings. Therefore, because it threatens the cognitive health of creatures, it needs more research.

Anxiogenic and anxiolytic effects of memantine injected into the ventral hippocampus in male stressed mice

OBJECTIVES

The effects of intra-ventral hippocampal memantine administration in male NMRI stressed mice were studied.

METHODS

Two stainless steel gauge 23 guide cannulas were placed in the middle part of the mice ventral hippocampus using stereotaxic coordination. Seven days later, the animals were undergone to the stress protocol as follows: They experience four consecutive electro-foot shock stress sessions lasting for 10 min. Five or 30 min before each stress session, the animals received intra-ventral hippocampal (0.1, 1 and, 5 µg/mouse) or intraperitoneal (1, 5, and 10 mg/kg) memantine respectively. Eight days after stress termination, the animals were tested either for the maintenance of either anxiety (elevated plus maze) or depression (forced swimming test).

RESULTS

Animals show anxiety eight days after stress termination. Intra-ventral hippocampal infusion of memantine (5 µg/mouse) 5 min before stress inhibited the anxiety-like behaviors. However, other doses of the drug exacerbate the stress effect. The drug, when injected peripherally exacerbated the stress effect in all doses. The drug by itself had no effect. In addition, animals also show depression nine days after stress termination and memantine (0.1, 1, and 5 µg/mouse) reduced the stress effect. The drug (0.1 µg/mouse) by itself induced depression in the animals. However, the drug when injected peripherally reduced the stress effect in all doses.

CONCLUSIONS

It could be concluded that NMDA glutamate receptors in the ventral hippocampus may play a pivotal role in the mediation of maintenance of anxiety and depression induced by stress in the mice.

The Effect of Brain Teaser Games on the Attention of Players Based on Hormonal and Brain Signals Changes

Introduction:

Computer games as an interactive media play a significant role in the cognitive and behavioral health of the players. Computer games have either positive or negative effects on cognitive indices among players. They also directly influence the lifestyle and quality of life of children, adolescents, and young adults. The present study aimed to evaluate the short-term effects of the brain teaser game on players.

Methods:

Among 45 male volunteers, 40 subjects with an average age of 20 years were recruited and divided into two groups: the experimental group and the control group. All required tests were conducted before and after the intervention (playing the game) on the experimental group. Also, the same tests were performed on the control group, in which the participants were not allowed to play the game. All participants completed a questionnaire comprised demographic characteristics and specific information regarding the game (e.g., game style and hours spent on playing the game). The saliva samples were collected to measure levels of cortisol and α-amylase. The salivary α-amylase (sAA) and cortisol levels were analyzed using the relevant ELISA kits. The cognitive tests were performed using PASAT software before and after the game to assess the perceptual-cognitive abilities of the players. The brain waveforms were acquired by a 14-channel Emotiv brain signal recording device before and after the game. Data analysis was conducted in R and MATLAB software.

Results:

PASAT test suggested that mental health and sustained attention were significantly improved after the intervention. In addition, the sAA and salivary cortisol levels were significantly higher before the intervention. The results of the brainwave analysis revealed that stress index and attention were significantly higher before the intervention.

Conclusion:

Findings of the present study suggest that brain teaser games positively influence the central nervous system and activate stress path, leading to changes in brain signals and subsequently improved cognitive elements, such as attention among players.

Environmental Effect of HV Towers at the Cerebellum and Cognitive Impairments in the Monkey

Today, living or working of people in the vicinity and even under the high-voltage lines is a pernicious environmental hazard to humans. The male rhesus monkey is used to investigate the effects of fields produced by high-voltage towers. In this study, the function and level of effect in rhesus monkeys' brain have been investigated in cerebellum's cognitive, biological and structural perspective. Two monkeys have been used, one as a control and the second under test. The monkey under test was subjected to a simulated HV electrical field of 3 kV/m for 4 hours a day for a one month. Behavioral tests were performed using a device designed and built for this purpose. Concentration analysis of adrenocorticotropic hormones (ACTH) and inspection of glucocorticoid receptor gene's (GR) expression were performed by the RT-PCR method. Changes in cerebellar anatomy with MRI images were examined. All tests were performed before and after the test period and were compared with the control monkey. Cognitive tests showed a significant reduction for the monkey that was exposed to a high-voltage electrical field in the first week after field imposition compared with the same time before. Also, the expression of the GR gene was decreased and the concentration of ACTH hormone in plasma was increased. Surveying the level of cerebral MRI images did not show any difference, but hemorrhage was evident in a part of the cerebellum. The results of cognitive, biological and MRI tests in the tested monkey showed a decrease in the visual learning and memory indices.

Pre-Clinical Evaluation of the Nanoliposomal antiPCSK9 Vaccine in Healthy Non-Human Primates

BACKGROUND

Our previous studies showed the safe preventive and therapeutic effects of immunization using the nanoliposomal antiPCSK9 vaccine called "Liposomal Immunogenic Fused PCSK9-Tetanus plus Alum adjuvant" (L-IFPTA), in mouse models of atherosclerosis. Here we aimed to ascertain the immunogenicity and safety of the L-IFPTA vaccine in a pre-clinical study in healthy non-human primates.

METHODS

Five male rhesus macaque monkeys were subcutaneously immunized with the L-IFPTA vaccine, four times with bi-weekly intervals. To evaluate immunogenicity, the plasma antiPCSK9 antibody in immunized monkeys was detected and quantified using the ELISA method. The functionality of the induced antiPCSK9 antibodies was determined by the PCSK9/LDLR in vitro binding assay kit. The safety of the vaccine was tested using the evaluation of several major circulating indicators including plasma lipid alterations, inflammatory biomarkers and organ injury biomarkers.

RESULTS

The resultant data indicated that the L-IFPTA vaccine significantly and highly induced the generation of functional and safe antiPCSK9 antibodies in immunized monkeys. Plasma levels of specific biomarkers indicating organ performance including creatinine, urea, uric acid, bilirubin, ALP, AS, ALT and TSH were not significantly altered. After immunization in healthy monkeys, non-prespecified endpoints (plasma levels of TC, LDL-C, VLDL-C and TG) were non-significantly reduced by 11.6 ± 36%; 16 ± 28%; 22 ± 53% and 24 ± 51%, respectively, while HDL-C was slightly increased by 2 ± 64%. There were also no significant changes in plasma levels of pro- and anti-inflammatory biomarkers.

CONCLUSION

The L-IFPTA vaccine could efficiently stimulate the host humoral immune response to produce active antibodies that inhibit plasma PCSK9 while not provoking systemic inflammation and not adversely affecting organ performance.

Prenatal Stress Induced Spatial Memory Deficit in a Sex-Specific Manner in Mice: Possible Involvement of Hippocampal Insulin Resistance

Introduction: In the present study, the effects of prenatal stress on spatial learning and memory deficit and its relationship with hippocampal insulin resistance was examined in male and female offspring. Method: Female NMRI mice were mate with males overnight and the zero day of pregnancy was detected (Gestational day zero-GD0). The pregnant mice were then randomly divided into stress and control groups. The stress group received stress from the GD0 to GD10. On post natal day 30 (PND30) the offspring were divided into for subgroups namely: male-control, female-control, male-stress, and female-stress. Barnes maze (BM) method was used for spatial learning evaluation. Plasma cortisol and insulin levels were measured at the beginning of the experiments. At the end of the experiments, the animals’ brains were removed and their hippocampus was extracted. The hippocampus was homogenized and its insulin and insulin receptor contents were evaluated. Results: The stressed animals needed more time for reaching to target hole. In addition, they spend more distance for finding the target hole, which was more pronounced in the male offspring. Both plasma and hippocampal insulin content were reduced in stressed groups. Moreover, the hippocampal insulin receptors protein was reduced in the stressed animals. There was a positive relationship between plasma and hippocampal content and memory deficit in the stressed groups. Conclusion: These results indicated that prenatal stress can induce spatial learning and memory deficit in offspring which is associated with plasma and hippocampal insulin and receptor content reduction (hippocampal insulin resistance) in these animals.

The effects of Valerian on sleep spindles in a model of neuropathic pain

Introduction

Valeriana officinalis is known to be one of the most famous herbal supplements for the treatment of anxiety and insomnia. Despite its widespread use in most countries all around the world, there is little scientific information and research on how this medication affects sleep patterns, and there are almost no studies on its effects on the characteristics of sleep spindles.

Material and Methods

The present study was conducted to investigate the effects of Valerian extract (VAL) on sleep spindles and induced anxiety in chronic neuropathic pain model in rats. 24 male rats were divided into three groups: neuropathic group (n=9) in which the rats underwent chronic constriction injury (CCI), sham group (n=7) in which the sciatic nerves of the animals were exposed without any constriction and also fed with the vehicle, and the third group was under CCI condition and treated with Valerian (n=8). All the rats underwent electrode implant surgery so that we could record electroencephalogram and electromyography waves. In all the three groups, EEG and EMG recordings were recorded three times (150min each time). The initial recording was just prior to the CCI surgery and the rest were 3 and 6 days following CCI surgery. Moreover, cold allodynia and elevated plus maze tests were performed 3 and 6 days following the CCI surgery.

Results

Valerian treatment could repair the allodynia induced by neuropathy. On the other hand, by Valerian treatment (400mg/kg) during neuropathy, the REM sleep, decreased and the non-REM sleep increased. Moreover, there was an increment in sleep spindle density and spindle frequency even in neuropathic condition.

Discussion

This herbal supplement improves the quality of sleep in neuropathy conditions.

The controlling role of nitric oxide within the shell of nucleus accumbens in the stress-induced metabolic disturbance

CONTEXT AND OBJECTIVES

The involvement of the nitricergic system within the shell part of the nucleus accumbens (NAc) was evaluated in the metabolic disturbances due to stress.

MATERIALS AND METHODS

Male Wistar rats were cannulated in the shell of the left NAc. They received either saline or different doses of L-arginine and/or L-NAME five minutes before each stress session, for four days. Plasma cortisol concentration, food and water intake, time elapsing for eating, animal weight changes and adrenal gland weight were recorded.

RESULTS

The L-arginine 1 μg/rat decreased the level of cortisol, water and food intake and time of feeding and increased the adrenal weight. But L-NAME at 1 μg/rat had opposite effects on these factors. However, the drugs showed similar effects at 10 μg/rat.

CONCLUSION

Injection of nitric oxide modifiers into the left side of NAc shell part may have an interactive role with sub-chronic stress in metabolic behaviour.

Changes in Cognitive Functions Following Violent and Football Video Games in Young Male Volunteers by Studying Brain Waves

Introduction:

This research investigated the effects of violent and football video games on cognitive functions, cortisol levels, and brain waves.

Methods:

A total of 64 participants competed in a single-elimination tournament. Saliva samples of all players were obtained before and after the games for the assessment of cortisol levels. The cognitive performances of the players were also assessed by paced auditory serial addition test. Moreover, the electroencephalogram recording was conducted during the games.

Results:

The results showed that salivary cortisol levels significantly decreased after playing both games. Also, playing the football game increased reaction time, whereas decreased sustained attention and mental fatigue.

Conclusion:

Conversely, following playing a violent game, the reaction time decreased, and sustained attention and mental fatigue increased. Furthermore, the results of the EEG recording revealed that playing a violent game engaged more brain regions than the football game. In conclusion, playing violent game more effectively improved cognitive performances in the players than the football game.

Fear stress in computer games caused brain waves, oxytocin and brain-derived neurotrophic factor changes among woman

Introduction: Stress and fear caused by computer games have been shown to have various effects on the cognitive system. This work was aimed to investigate the effects of short-time horror computer games on cognitive indicators. Methods: A total of twenty female subjects were recruited and divided into experimental and control groups. All required tests were performed before and after the intervention (playing or watching horror game) on the control and experimental groups. The saliva samples were collected before and after the intervention to measure levels of cortisol and alpha-amylase. Also, blood was taken before and during the game from each subject to evaluate plasma levels of oxytocin and brain-derived neurotrophic factor. The Brain waveforms were acquired by Emotive brain signal recording device before and after the intervention. Data analysis was conducted using R and MATLAB software. Results: The cortisol and alpha-amylase levels were shown to significantly increase after the horror game playing. Also, the levels of oxytocin were significantly higher after the experimentation. The levels of brain-derived neurotrophic factor were displayed to reduce after the experimentation. The results of the brainwave analysis revealed that the average stress index was significantly higher, while the average attention index was lower after playing the game. No significant difference in the study variables was observed in the control group. Conclusion: Horror computer games may have adverse effects on the activity of the stress system in the central nervous system. Fear-induced stress was shown to relatively undermine some cognitive elements.

Stress-Induced Spatial Memory Deficit Reversed by Basolateral Amygdala NMDA Receptor Inhibition in Male Wistar Rats

INTRODUCTION

The present study investigated the role of the Basolateral Amygdala (BLA) N-methyl-D-aspartate (NMDA) receptors in stress-induced spatial memory disturbance among the male Wistar rats.

METHODS

The male Wistar rats (Average weight =200 g) were cannulated bilaterally in the BLA, and entered the study (n=6-8) after one week. They received seven electro-foot-shock stress sessions on seven consecutive days. Memantine (0.1, 1, and 5 μg/rat) or saline (0.5 μL/ rat) was injected into the BLA, five minutes before each stress session. The control groups received the same doses of memantine and no stress. After the end of the stress sessions, blood samples were taken from all animals to evaluate their plasma corticosterone. Also, the spatial learning and memory of the study animals were evaluated using the Barnes maze method. The animals experienced five consecutive days of training on the maze for spatial learning. On the sixth day, their spatial memory was evaluated on the maze. Time, distance, the number of errors, and the taking strategy for reaching the target hole were considered as the parameters for the spatial learning and memory evaluation.

RESULTS

Stress increases the plasma corticosterone level, while memantine preadministration reduces the stress effects. Besides, stress increases the time and distance to the target hole and the number of errors. Stress changed the animals' strategy from serial to random type. However, the intra-BLA memantine reversed all the disturbances induced by the stress.

CONCLUSION

This study indicated that the BLA glutamate NMDA receptors modulate the effect of stress on spatial learning and memory deficit.

Ventral tegmental area inactivation alters hormonal, metabolic, and locomotor responses to inescapable stress

Context: The involvement of unilateral and bilateral inhibition of the ventral tegmental area (VTA) in response to stress is not well understood. Objective: In the present study, the effect of unilateral and bilateral inhibition of the VTA on hormonal, metabolic, and locomotor responses to stress was assessed. Material and methods: Male rats seven days after cannulation into the VTA received electro foot-shock stress for seven consecutive days. Twenty minutes before induction of stress, 2% lidocaine hydrochloride or sterile saline (control) was injected either uni- or bi-laterally into the VTA. Results: Results showed that stress significantly increased serum corticosterone level, adrenal gland weight and anorexia, reduced weight gain, food-intake, and locomotor activity. However, bilateral inactivation of VTA prevented stress-induced these parameters changes. Conclusion: The present study demonstrated that the bilateral VTA blockade effectively relieves the symptoms of stress, while the unilateral VTA blockade does not significantly improve the changes caused by stress.

Protective properties of the aqueous extract of saffron (Crocus sativus L.) in ischemic stroke, randomized clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Crocus sativus L. has been used throughout the world in traditional medicine as a treatment for neurological disorders such as depression. Growing attention is currently being paid to the use of neuroprotective agents in ischemic strokes.

AIM OF THE STUDY

This study assed the effect of saffron as a neuroprotective natural product in cerebral ischemia in human.

STUDY DESIGN

Patients with acute ischemic stroke were randomly allocated to receive either routine stroke care (control group, n = 20) or routine care plus aqueous extract of saffron capsule (200 mg/day) (saffron-treated group, n = 19). Both groups were monitored during their four-day hospital stay and the three-month follow-up period. The groups were compared in terms of short- and long-term effects of saffron capsules using the National Institute of Health Stoke Scale (NIHSS), Barthel Scale, and serum neuron specific enolase (NSE), Brain-derived neurotrophic factor (BDNF), S100 levels.

RESULTS

Based on the NIHSS, the severity of stroke during the first four days was significantly lower in the saffron-treated group than in the control group (P < 0.05). Compared to the levels on the first day, serum NSE and s100 levels were significantly decreased and BDNF concentration was increased in the saffron-treated group on the fourth day. Also, our results showed there was a negative significant non-linear cubic regression between BDNF concentration and score of NIHSS. At the end of the three-month follow-up period, the mean Barthel index was significantly higher in the saffron-treated group than in the control group (P < 0.001).

CONCLUSION

The results of this study confirmed the short and long-term neuroprotective effects of aqueous extract of saffron on ischemic stroke in humans.

Effect of Nitric Oxide on Basolateral Amygdala on Persistence of Anxiety and Depression in Stressed Male Rats

Introduction:

The current study aimed at investigating the role of Nitric Oxide (NO) in the maintenance of anxiety and depression induced by stress in male Wistar rats using intra-Basolateral Amygdala (BLA) injection of NO precursor, L-arginine, Nitric Oxide Synthase (NOS) inhibitor, and L-NAME.

Methods:

Two 23-gauge stainless steel cannulas were placed in the BLA, stereotaxically. Seven days later, animals experienced electro foot shock stress based on the following protocol: animals experienced four sessions of stress for 60 minutes in four consecutive days. Five minutes before each stress session, the animals received different doses of L-arginine or L-NAME (1, 5 and, 10 μg/rat) or saline (0.5 μL/rat) intra-BLA. Six days after the stress termination, animals were tested for maintenance of anxiety-like behavior (elevated plus maze; EPM) and eight days after the stress they were examined for depression (forced swimming test; FST).

Results:

Stress reduced the time and number of open arms and decreased motor activity on EPM. Stress-induced anxiety was inhibited by L-arginine and L-NAME (1, 5, and 10 μg/rat). L-Arginine and L-NAME induced anxiety in non-stressed rats. Stress also increased the immobility time in animals in FST paradigm. Interestingly, both L-arginine and L-NAME, in all doses reduced the stress effect.

Conclusion:

BLA nitric oxide may play a pivotal role in anxiety and depression induced by stress in rats. Since the effects of both L-arginine and L-NAME were similar, NO might have a modulatory role in the BLA.

GABAB receptor activation ameliorates spatial memory impairments in stress-exposed rats

Objective: Due to the prevalence of stress in modern life and its impact on spatial memory, the role of inhibitory systems in brain areas such as the nucleus accumbens (NAc) in reducing stress is important. The current study aimed to examine the response of NAc shell GABA_B receptors to stress and the role of intraperitoneally (i.p.) and intra-NAc injection of the GABA_B receptor agonist baclofen on spatial memory impairments in stress-exposed rats. Methods: Eighty adult male Wistar rats were randomly divided into ten groups (n=8): two were control groups for intra-NAc and i.p baclofen; two groups were subjected to stress and injected with saline (baclofen vehicle); three groups were given baclofen (1, 5, and 10 µg/rat) intra-NAc 5 mins before stress was induced; and three groups received baclofen (1, 5, and 10 mg/kg/i.p.) 30 mins before being subjected to stress. Foot-shock stress was applied for 7 consecutive days. Behavioral assays using the Barnes maze were performed 24 hrs after the last baclofen injection. Results: Both the intra-NAc and the i.p administration of baclofen dose-dependently reduced escape latency and total distance and increased velocity in the treatment groups in the training trials. In the probe test, the rats that had received 5 mg/kg of baclofen had the highest target frequency, but there no significant differences were observed in velocity, duration, or distance to the target between the groups. Conclusion: According to the findings, baclofen can dose-dependently improve spatial memory, and GABA_B receptor in the NAc plays an important role in spatial memory.

Maternal separation blunted spatial memory formation independent of peripheral and hippocampal insulin content in young adult male rats

This study explores the effects of maternal separation as a chronic early life stress (ELS) on pancreatic islets insulin content and secretion, and their potential relationship with the hippocampus insulin content and spatial memory in young adulthood. Male rat offspring were divided into two groups: stress (STR) and non-stress (non-STR) groups. The animals of the STR group were separated from their mothers during postnatal days (PND) 1 to 21. During the weaning time, that is, PND-0 to PND-21, the body weight and length of the pups were measured. Blood samples were collected on PND-1, 21, 29 and 34 and during young adulthood (53±2 days) to determine plasma corticosterone and insulin levels. The young adult animals were also tested for spatial memory. One day after the memory test, the animals were decapitated and their pancreases were removed to measure the islets insulin content and secretion. Finally, the animals' hippocampi were isolated to determine their insulin content and insulin receptor protein amounts. During the period of weaning, the body weight and length of pups belonging to the STR group were significantly lower as compared to those in the non-STR group. Maternal separation did not change the plasma levels of insulin but increased plasma corticosterone levels from PND-21 to young adulthood and also reduced the islets insulin content but did not affect insulin secretion and the hippocampus insulin content and insulin receptor protein amount. Although, at the end of the memory tests, rats of the STR group reached the escape box at almost the same time and distance and with the same errors as rats of the non-STR group, the distance traveled to reach the escape box showed a steep reduction in the non-STR group as compared to the STR group after the first trial. Moreover, as compared to the STR group, the non-STR group showed an increasing trend for direct strategy to find the escape box. The islets insulin content and secretion, and the plasma insulin concentration were not significantly correlated with the hippocampus insulin content. From the results of the present study, it appears that the main behavioral effect of the maternal separation stress in the spatial memory task was to impair the strategy used by the animals to reach the escape box. This may indicate that maternal separation stress affects brain regions other than the hippocampus. Moreover, due to the reduction of the body weight and length of offspring belonging to the STR group, it should be further considered that both maternal separation and early life malnutrition are directly (and mechanistically) linked to cognitive alterations later in life in ways that are not dependent on peripheral and hippocampal insulin content.

The Beneficial or Harmful Effects of Computer Game Stress on Cognitive Functions of Players

Introduction:

Video games are common cultural issues with great influence in all societies. One of the important cognitive effects of video games is on creating stress on video players. The present research objective was to study different types of stress in players based on video game styles.

Methods:

A total of 80 players, aged 18 to 30 years, played four types of video games; Runner game, Excitement game, Fear game, and Puzzle game. In the beginning, the players filled in the form of personal information as well as some general and specialized information on the games. Before starting each game, the saliva samples of the players were collected to measure their level of cortisol and α-amylase. At the end of each game, the same samples were collected again. The concentrations of cortisol and α-amylase were measured using a specialized kit and an ELISA device. In addition, the variations of brain waves were recorded by an Emotiv system. Finally, the data were analyzed in SPSS and Matlab system (after and before playing video game).

Results:

The research findings revealed that the salivary α-amylase concentration increased significantly after playing the Fear game, Runner game, and Excitement game and decreased significantly after playing the Puzzle game. Moreover, the concentration of salivary cortisol increased significantly after playing the Runner game, Excitement game, and Fear game and decreased significantly after playing the Puzzle game. The brain wave analysis also revealed that the level of stress experienced by playing Fear game was higher than the Excitement game.

Conclusion:

According to the research findings, video games can affect the stress system as well as the cognitive system of humans depending on the game style. In addition, the type and level of stress triggered in the players depend on the game style.

Effects of the Extremely Low Frequency Electromagnetic Fields on NMDA-Receptor Gene Expression and Visual Working Memory in Male Rhesus Macaques

Introduction

The present research aimed to examine Visual Working Memory (VWM) test scores, as well as hormonal, genomic, and brain anatomic changes in the male rhesus macaques exposed to Extremely Low Frequency Magnetic Field (ELF-MF).

Methods

Four monkeys were exposed to two different ELF-MF frequencies: 1 Hz (control) and 12 Hz (experiment) with 0.7 μT (magnitude) 4 h/d for 30 consecutive days. Before and after the exposure, VWM test was conducted using a coated devise on a movable stand. About 10 mL of the animals' blood was obtained from their femoral vain and used to evaluate their melatonin concentration. Blood lymphocytes were used for assaying the expressions of N-Methyl-D-aspartate NMDA-receptor genes expression before and after ELF exposure. Anatomical changes of hippocampus size were also assessed using MRI images.

Results

Results indicated that VWM scores in primates exposed to 12 Hz frequency ELF increased significantly. Plasma melatonin level was also increased in these animals. However, these variables did not change in the animals exposed to 1 Hz ELF. At last, expression of the NMDA receptors increased at exposure to 12 Hz frequency. However, hippocampal volume did not increase significantly in the animals exposed to both frequencies.

Conclusion

In short, these results indicate that ELF (12 Hz) may have a beneficial value for memory enhancement (indicated by the increase in VWM scores). This may be due to an increase in plasma melatonin and or expression of NMDA glutamate receptors. However, direct involvement of the hippocampus in this process needs more research.

The Psychoactive Agent Crocin Can Regulate Hypothalamic-Pituitary-Adrenal Axis Activity

Post-traumatic stress disorder (PTSD) occurs following life-threatening events. The activity of the hypothalamic-pituitary-adrenal (HPA) axis, which serves as the first line of defense against stress, is dysfunctional in this disorder. The current study aimed to investigate the role of Crocin in normalizing HPA function in an animal model of PTSD induced by electric foot shock. Rats were treated with Crocin 5 min prior to stress induction. The stimulus was re-introduced after 21 days, and we measured individual behaviors such as sniffing, rearing, grooming, and freezing. Enzyme-linked immunosorbent assays were performed to measure plasma levels of Corticosterone. On day 28, after rats were weighed and sacrificed, the adrenal and thymus glands were removed and subjected to real-time polymerase chain reaction to quantify the gene expression of corticotrophin-releasing hormone (CRH), glucocorticoid receptor (GluR), and arginine vasopressin (AVP). Our results demonstrate that rats re-exposed to a stressor developed characteristic symptoms of PTSD, but these were attenuated by Crocin. Treated rats showed significant changes in CRH expression in the hypothalamus, GluR expression in the pituitary, plasma Corticosterone levels, and freezing behavior. Together, these findings suggest that Crocin can regulate HPA axis activity in PTSD. It may serve an appropriate treatment for subjects who experience a traumatic event.

Role of basal stress hormones and amygdala dimensions in stress coping strategies of male rhesus monkeys in response to a hazard-reward conflict

OBJECTIVES

In the present study the effect of stress on monkeys that had learned to retrieve food from a five-chamber receptacle, as well as the relationship between their behavior and the serum cortisol and epinephrine levels and relative size of the amygdala was evaluated.

MATERIALS AND METHODS

Six male rhesus monkeys were individually given access to the food reward orderly. They could easily retrieve the rewards from all chambers except for the chamber 4, which a brief, mild electric shock (3 V) was delivered to them upon touching the chamber's interior. The coping behaviors were video-recorded and analyzed offline. Baseline serum cortisol and epinephrine levels were measured before the experiments using monkey enzyme-linked immunosorbent assay kit. One week after the behavioral experiment, the monkeys' brains were scanned using magnetic resonance imaging under general anesthesia. The cross-sectional area of the left amygdala in sagittal plane relative to the area of the whole brain in the same slice was evaluated by the planimetric method using ImageJ software.

RESULTS

Exposure to the distressing condition caused different behavioral responses. Monkeys with higher baseline levels of serum cortisol and epinephrine and larger amygdala behaved more violently in the face of stress, indicating adopting emotion-focused stress-coping strategies. Conversely, those with low plasma epinephrine, moderate cortisol, and smaller amygdala showed perseverative behavior, indicating a problem-focused coping style.

CONCLUSION

In dealing with the same stress, different responses might be observed from nonhuman primates according to their cortisol and epinephrine levels as well as their amygdala dimensions.

The impact of stress on body function: A review

Any intrinsic or extrinsic stimulus that evokes a biological response is known as stress. The compensatory responses to these stresses are known as stress responses. Based on the type, timing and severity of the applied stimulus, stress can exert various actions on the body ranging from alterations in homeostasis to life-threatening effects and death. In many cases, the pathophysiological complications of disease arise from stress and the subjects exposed to stress, e.g. those that work or live in stressful environments, have a higher likelihood of many disorders. Stress can be either a triggering or aggravating factor for many diseases and pathological conditions. In this study, we have reviewed some of the major effects of stress on the primary physiological systems of humans.

Transient Inactivation of Shell Part of Nucleus Accumbens Inhibits and Exacerbates Stress-Induced Metabolic Alterations in Wistar Rats

Introduction:

The role of different parts of the extended amygdala in metabolic signs of stress is not well understood. In the present study, we decided to evaluate the impact of the shell part of nucleus accumbens (NAc) on metabolic disturbance induced by electro foot shock stress using transient inactivation method in the rat.

Methods:

Male Wistar rats (W: 230–250 g) were canuulated unilaterally in the shell part of nucleus accumbens and left one week for recovery. Five minutes before each stress session, the animals either received sterile saline (0.25 μl/side) (control) or lidocaine 2% (0.25 μl/side) (experiment). Blood samples were taken from rats’ retro-orbital sinus for plasma corticosterone measurements. In addition, animals’ weight gain, food and water intake, locomotor activity, and rearing were recorded.

Results:

Stress reduced weight gain and food intake, increased water intake and plasma corticosterone level, and reduces locomotor activity and rearing. Transient inactivation of the right side of the NAc inhibits the stress effect on weight gain, water intake and plasma corticosterone level, but not food intake. However, when the left side of the NAc was inactivated, only weight gain was affected and other parameters were not differing from stress group. Even thought, the plasma corticosterone level was elevated.

Conclusion:

In conclusion, our data indicated that right side of shell part of NAc transient inactivation leads to reduction in metabolic signs of stress but left side of shell part of the NAc inactivation even exacerbates stress signs.

The Effect of 20 Minutes Scuba Diving on Cognitive Function of Professional Scuba Divers

BACKGROUND

Physical activity increases the performance of the nervous system by stimulating the body's metabolism and improving the efficiency of the ATP production system.

OBJECTIVES

In the present study, the effect of twenty minutes scuba diving in high depth (10m) on cognitive function and stress system activity was investigated.

METHODS

Twelve professional scuba divers with a mean age of 23 ± 1 year, weight of 80 ± 2.5 kg and height of 1.79 ± 3.5 cm resident in the city of Mashhad participated in the test. Their cognitive functions were measured 60 min before and 20 min after diving and the data were evaluated using the PASAT software. In the present study, parameters such as general mental health, sustained attention, average response speed, and mental fatigue were measured. Moreover, in order to determine the activity of the stress system, their salivary cortisol was collected before and after diving.

RESULTS

Results revealed that, the general mental health of these scuba divers was normal and it did not undergo a remarkable change after diving. Their average response speed and sustained attention had a significant decrease after scuba diving. Mental fatigue after diving increased. Also, salivary cortisol level significantly increased after diving.

CONCLUSIONS

According to our data, it seems that scuba diving as stress stimulant increases cortisol level and therefore reduces cognitive performance after diving.

Papaver Rhoeas L. Hydroalcoholic Extract Exacerbates Forced Swimming Test-Induced Depression in Mice

Introduction:

Depression is one of the most frequent psychiatric disorders in the world with occurs with higher incidence in women. In the present study, the effect of water-alcoholic extract of Papaver rhoeas L. on forced swimming test (FST) in Swiss-Webster mice were examined.

Methods:

We used Swiss-Webster mice (20–25 g) to execute FST on them. The plant extract (1, 10, 30, and 100 mg/kg) was injected to the animals 30 minutes before each session. Fluoxetine (20 mg/kg) was used as standard antidepressant drug. In another group of animals, 30 minutes after extract administration, blood samples were taken from retro-orbital sinus for corticosterone assay. Yet in third group, the drugs were injected to the animals and 30 minutes later, their activities were tested in an open field apparatus.

Results:

Our experiments showed that the extract efficiently reduced FST time both in male and female mice dose-dependently. This effect was comparable with fluoxetine. In addition, corticosterone assay indicated that plasma corticosterone in animals which received extract was higher than those amounts in fluoxetine and saline controls. Moreover, the animals did not show any motor activity deficit in all doses of the extract and fluoxetine compared to saline control.

Conclusion:

The extract of Papaver rhoeas can reduce immobility time which is comparable to the effect of fluoxetine. Also the effect of the extract is contrary to its effects on plasma corticosterone level and or animals’ activity.

Transient inactivation of the nucleus accumbens (NAc) shell prominently ameliorates responses to acute stress in female rats

It is clear that the stress response differs between females and males. Moreover, the nucleus accumbens shell is considered a critical area in the brain's response to stress. In the present study we investigate the effect of the transient inactivation of the NAc shell on the metabolic and hormonal disturbance induced by acute stress in female rats. Female Wistar rats were canulated uni- or bilaterally in the NAc shell before stress induction. Electric foot shock was applied to the animals and lidocaine hydrochloride was administered intra-acumbally 5min before each stress session. Food and water intake, delay to eating time, plasma corticosterone, estradiol and progesterone were measured after stress administration. Our results indicate that food intake increased whereas water intake decreased in stress group, furthermore, delay in the onset of eating also was observed. In addition, plasma corticosterone and progesterone concentrations were increased whereas estradiol was decreased. Transient inactivation of right side of NAc shell inhibited the stress effect on food intake; however, the effect of stress was exacerbated when the left part of the NAc shell was inhibited. Transient inactivation of both NAc shell sides augmented the stress effect on water intake. The same results also obtained for the effect of stress on delay to eating time. Lidocaine administration inhibited the effects of stress on all of the hormones we tested. It can be concluded that the NAc shell plays an important role in the mediation of stress responses in female rats and this influence shows asymmetrical manner.

Temporary amygdala inhibition reduces stress effects in female mice

The current study investigated the effect of temporary inhibition of amygdala in response to metabolic changes caused by stress in female mice. Unilateral and bilateral amygdala cannulation was carried out, and after a week of recovery, 2% lidocaine hydrochloride was injected into the mice amygdalae five minutes before the induction of stress. A communication box was employed to induce stress for four consecutive days and plasma corticosterone, food and water intake, weight changes, and anorexia were measured as stress-induced metabolic changes. Results demonstrated that stress, increases stress, increased plasma corticosterone concentrations, weight, food, and water intake. Temporary inhibition of the amygdala slightly decreased plasma corticosterone concentrations, but did not fully reduce the effect of stress. The bilateral injection of lidocaine hydrochloride to the amygdala reduced the effect of stress and reduced water intake and weight. Unilateral injection of lidocaine hydrochloride into the left and right amygdala reduced food intake. In conclusion, the present study demonstrated that the left side and right side of amygdala nuclei play a different role in metabolic responses in stress.

Evaluation of the Effect of Time Change in Cognitive Function in Volunteers in Tehran

<strong></strong><p><strong>BACKGROUND:</strong> Time change (which can lead to sleep duration decrements) can lead to brain dysfunction if repeated. In the present study, cognitive functions of the volunteers were evaluated before and after the time changes in Tehran.</p><p><strong>METHODS:</strong> Eleven, voluntary healthy persons (21±2 year old) were evaluated for their cognitive functions including sustain attention, reaction time, and mental fatigue twenty-one days before the time changes and thirty-eight days after time change using PASAT software. In addition, plasma cortisol level was measured before and after the time changes.</p><p><strong>RESULTS:</strong> After the time changes salivary cortisol concentration increase, but general mental health was decreased. Sustain attention was shortened after time change which was significantly different compared with before the time changes. Reaction time was increased after the time changes in comparison with the before the time changes, but was not statistically significant. In addition, mental fatigue was increased after the time changes.</p><p><strong>CONCLUSION:</strong> It seems that time change may reduce brain cognitive functions which are manifested by general mental health, sustain attention reduction, reaction time as well as mental fatigue.</p>

Role of Nitric Oxide on Dopamine Release and Morphine-Dependency

The catastrophic effects of opioids use on public health and the economy are documented clearly in numerous studies. Repeated morphine administration can lead to either a decrease (tolerance) or an increase (sensitization) in its behavioral and rewarding effects. Morphine-induced sensitization is a major problem and plays an important role in abuse of the opioid drugs. Studies reported that morphine may exert its effects by the release of nitric oxide (NO). NO is a potent neuromodulator, which is produced by nitric oxide synthase (NOS). However, the exact role of NO in the opioid-induced sensitization is unknown. In this study, we reviewed the role of NO on opioid-induced sensitization in 2 important, rewarding regions of the brain: nucleus accumbens and ventral tegmentum. In addition, we focused on the contribution of NO on opioid-induced sensitization in the limbic system.

Effects of Memantine, an NMDA Antagonist, on Metabolic Syndromes in Female NMRI Mice

INTRODUCTION

The brain glutamate neurotransmitter system and its NMDA (N-methyl-D-aspartate) receptors in the nucleus accumbens play an important role in the incidence of sensitivity and addiction. The present study examined the inhibitory effect of glutamate NMDA receptors in the nucleus accumbens in response to chronic stress.

METHODS

After the unilateral and bilateral placement of cannula(e) in the nucleus accumbens, one group of the animals received different doses of intra-accumbens memantine (0.1, 0.5 and 1 μg/mouse) 5 minutes before receiving the electric shock stress at their soles (using a Communication Box) and the other group received intraperitoneal memantine (doses of 0.1, 0.5 and 1mg/kg) 30 minutes before receiving the same shock. Chronic stress increased the animals' weight, plasma corticosterone, food and water intake, but reduced their defecation rates and eating latency.

RESULTS

The intraperitoneal administration of memantine increased plasma corticosterone, water intake, fecal weight, and eating latency, but had no effect on food intake or weight. The dose and site-dependent intra-accumbens administration of memantine either exacerbated the effects of stress on plasma corticosterone levels, water and food intake, or had no effect on these parameters. Furthermore, the administration of memantine had no effect on animal's weight and inhibited the effects of stress on fecal weight and eating latency.

DISCUSSION

The inhibition of glutamate NMDA receptors in the nucleus accumbens can inhibit and/or exacerbate the dose and site-dependent effects of chronic stress, and gender plays a significant role in producing this effect too.

Effect of Transient Inactivation of Ventral Tegmental Area on the Expression and Acquisition of Nicotine-Induced Conditioned Place Preference in Rats

Background:

Nicotine can activate dopaminergic neurons within the ventral tegmental area (VTA). However, there is no evidence about complete inhibition of VTA on nicotine reinforcement.

Methods:

in the present study, we used conditioned-place preference (CPP) method to study the effect of transient inhibition of left and/or right side of the VTA by lidocaine on nicotine reward properties. Male Wistar rats seven days after recovery from surgery and cannulation were conditioned to nicotine (1.5 mg/kg) in an unbiased designed CPP apparatus. Five min before each nicotine injection in conditioning phase, lidocaine (2%) was administered either uni- or bi-laterally into the VTA (0.5µl/rat).

Results:

results revealed that lidocaine administration into the left but not right side of the VTA reduced nicotine CPP significantly. The reduction was potentiated when lidocaine injected in to both sides of the VTA. In addition, the number of compartment crossing was reduced when lidocaine injected in both side of VTA as well as left side. On the other hand, rearing was reduced when lidocaine injected to the right but not left side of VTA. At last, sniffing was reduced only in the group in which received lidocaine in both side of VTA. Sniffing and rearing increased in the group in which received lidocaine in right side.

Conclusion:

It is concluded that the right and left side of VTA play different role in nicotine-induced activity and reward.