Potential contribution of oxidative stress and inflammation to anxiety and hypertension

Tempol treatment reduces anxiety-like behaviors induced by multiple anxiogenic drugs in rats

We have published that pharmacological induction of oxidative stress (OS) causes anxiety-like behavior in rats. Using animal models, we also have established that psychological stress induces OS and leads to anxiety-like behaviors. All evidence points towards the causal role of OS in anxiety-like behaviors. To fully ascertain the role of OS in anxiety-like behaviors, it is reasonable to test whether the pro-anxiety effects of anxiogenic drugs caffeine or N-methyl-beta-carboline-3-carboxamide (FG-7142) can be mitigated using agents that minimize OS. In this study, osmotic pumps were either filled with antioxidant tempol or saline. The pumps were attached to the catheter leading to the brain cannula and inserted into the subcutaneous pocket in the back pocket of the rat. Continuous i.c.v. infusion of saline or tempol in the lateral ventricle of the brain (4.3 mmol/day) was maintained for 1 week. Rats were intraperitoneally injected either with saline or an anxiogenic drug one at a time. Two hours later all groups were subjected to behavioral assessments. Anxiety-like behavior tests (open-field, light-dark and elevated plus maze) suggested that tempol prevented anxiogenic drug-induced anxiety-like behavior in rats. Furthermore, anxiogenic drug-induced increase in stress examined via plasma corticosterone and increased oxidative stress levels assessed via plasma 8-isoprostane were prevented with tempol treatment. Protein carbonylation assay also suggested preventive effect of tempol in the prefrontal cortex brain region of rats. Antioxidant protein expression and pro-inflammatory cytokine levels indicate compromised antioxidant defense as well as an imbalance of inflammatory response.

Anxious phenotypes plus environmental stressors are related to brain DNA damage and changes in NMDA receptor subunits and glutamate uptake

This study aimed at investigating the effects of chronic mild stress on DNA damage, NMDA receptor subunits and glutamate transport levels in the brains of rats with an anxious phenotype, which were selected to represent both the high-freezing (CHF) and low-freezing (CLF) lines. The anxious phenotype induced DNA damage in the hippocampus, amygdala and nucleus accumbens (NAc). CHF rats subjected to chronic stress presented a more pronounced DNA damage in the hippocampus and NAc. NMDAR1 were increased in the prefrontal cortex (PC), hippocampus and amygdala of CHF, and decreased in the hippocampus, amygdala and NAc of CHF stressed. NMDAR2A were decreased in the amygdala of the CHF and stressed; and increased in CHF stressed. NMDRA2A in the NAc was increased after stress, and decreased in the CLF. NMDAR2B were increased in the hippocampus of CLF and CHF. In the amygdala, there was a decrease in the NMDAR2B for stress in the CLF and CHF. NMDAR2B in the NAc were decreased for stress and increased in the CHF; in the PC NMDAR2B increased in the CHF. EAAT1 increased in the PC of CLF+stress. In the hippocampus, EAAT1 decreased in all groups. In the amygdala, EAAT1 decreased in the CLF+stress and CHF. EAAT2 were decreased in the PC for stress, and increased in CHF+control. In the hippocampus, the EAAT2 were increased for the CLF and decreased in the CLF+stress. In the amygdala, there was a decrease in the EATT2 in the CLF+stress and CHF. These findings suggest that an anxious phenotype plus stress may induce a more pronounced DNA damage, and promote more alterations in the glutamatergic system. These findings may help to explain, at least in part, the common point of the mechanisms involved with the pathophysiology of depression and anxiety.

Effects of centrally administered etanercept on behavior, microglia, and astrocytes in mice following a peripheral immune challenge

Peripheral cytokines affect central nervous system (CNS) function, manifesting in symptoms of anxiety and cognitive decline. Although the peripheral blockage of tumor necrosis factor (TNF)-α has been effective in alleviating depression and rheumatoid arthritis, it is yet unknown whether central blockade of TNF-α is beneficial for immune-challenged CNS function. This study investigated the effects of central etanercept administration following a peripheral immune challenge on anxiety-like and cognition-like behaviors and microglia and astrocyte numbers. Twelve-week-old C57BL/6 mice (n=40) were treated with either LPS or saline administered peripherally 24 h before being treated with either etanercept or artificial CSF (aCSF) by intracerebroventricular injection. Mice underwent behavioral analyses for locomotion, memory, and anxiety-like behavior 24 h post-etanercept/aCSF treatment, and tissue was collected to estimate the numbers of hippocampal microglia and astrocytes. Following peripheral immune challenge with LPS, mice showed increased anxiety-like behavior, which was significantly improved following treatment with etanercept (two-way ANOVA: Interaction: F(1,30)=0.60, P=0.44; Saline/LPS challenge: F(1,30)=23.92, P<0.0001, etanercept vs aCSF: F(1,30)=11.09, P=0.0023). For cognition, a significant interaction effect found by two-way ANOVA (Interaction: F(1,20)=4.96, P=0.037, Saline/LPS challenge: F(1,20)=4.966, P=0.31, aCSF/etanercept treatment: F(1,20)=0.06, P=0.80) and post-hoc analysis revealed a significant decrease in cognition in LPS-aCSF compared with Sal-aCSF mice (P=0.038), but no significant difference was noted between LPS-aCSF and LPS-Etan mice (P>0.9). A significant reduction in the number of microglia within the hippocampus of these mice was noted (two-way ANOVA: Interaction: F(1,15)=11.41, P=0.0041; Saline/LPS challenge: F(1,15)=50.13, P<0.0001, etanercept vs aCSF: F(1,15)=3.36, P=0.08). Centrally administered etanercept improved anxiety-like behavior but not spatial memory under a peripheral immune challenge and was associated with a decrease in the hippocampal microglia numbers. This suggests that etanercept recovers anxiety-like behavior possibly mediated by a reduction of TNF-α-related central inflammation.

Identification of hypertensive patients with dominant affective temperaments might improve the psychopathological and cardiovascular risk stratification: a pilot, case-control study

BACKGROUND

Although mood disorders and cardiovascular diseases have widely studied psychosomatic connections, data concerning the influence of the psychopathologically important affective temperaments in hypertension are scarce. To define a possibly higher cardiovascular risk subpopulation we investigated in well-treated hypertensive patients with dominant affective temperaments (DOM) and in well-treated hypertensive patients without dominant temperaments the level of depression and anxiety, arterial stiffness and serum Brain-derived Neurotrophic Factor (seBDNF).

METHODS

175 hypertensive patients, free of the history of psychiatric diseases, completed the TEMPS-A, Beck Depression Inventory and Hamilton Anxiety Scale questionnaires in two primary care practices. Of those 175 patients, 24 DOM patients and 24 hypertensive controls (matched in age, sex and the presence of diabetes) were selected for measurements of arterial stiffness and seBDNF level.

RESULTS

Beck and Hamilton scores in DOM patients were higher compared with controls. Pulse wave velocity and augmentation index did not differ between the groups while in the DOM patients decreased brachial systolic and diastolic and central diastolic blood pressures were found compared with controls. SeBDNF was lower in the DOM group than in the controls (22.4 ± 7.2 vs. 27.3 ± 7.8 ng/mL, p < 0.05).

CONCLUSIONS

Although similar arterial stiffness parameters were found in DOM patients, their increased depression and anxiety scores, the decreased brachial and central diastolic blood pressures as well as the decreased seBDNF might refer to their higher vulnerability regarding the development not only of major mood disorders, but also of cardiovascular complications. These data suggest that the evaluation of affective temperaments should get more attention both with regard to psychopathology and cardiovascular health management.

Mitochondrial Gene Expression Profiles and Metabolic Pathways in the Amygdala Associated with Exaggerated Fear in an Animal Model of PTSD

The metabolic mechanisms underlying the development of exaggerated fear in post-traumatic stress disorder (PTSD) are not well defined. In the present study, alteration in the expression of genes associated with mitochondrial function in the amygdala of an animal model of PTSD was determined. Amygdala tissue samples were excised from 10 non-stressed control rats and 10 stressed rats, 14 days post-stress treatment. Total RNA was isolated, cDNA was synthesized, and gene expression levels were determined using a cDNA microarray. During the development of the exaggerated fear associated with PTSD, 48 genes were found to be significantly upregulated and 37 were significantly downregulated in the amygdala complex based on stringent criteria (p < 0.01). Ingenuity pathway analysis revealed up- or downregulation in the amygdala complex of four signaling networks – one associated with inflammatory and apoptotic pathways, one with immune mediators and metabolism, one with transcriptional factors, and one with chromatin remodeling. Thus, informatics of a neuronal gene array allowed us to determine the expression profile of mitochondrial genes in the amygdala complex of an animal model of PTSD. The result is a further understanding of the metabolic and neuronal signaling mechanisms associated with delayed and exaggerated fear.

TrkB overexpression in mice buffers against memory deficits and depression-like behavior but not all anxiety- and stress-related symptoms induced by developmental exposure to methylmercury

Developmental exposure to low dose of methylmercury (MeHg) has a long-lasting effect on memory and attention deficits in humans, as well as cognitive performance, depression-like behavior and the hippocampal levels of the brain-derived neurotrophic factor (Bdnf)in mice. The Bdnf receptor TrkB is a key player of Bdnf signaling. Using transgenic animals, here we analyzed the effect of the full-length TrkB overexpression (TK+) on behavior impairments induced by perinatal MeHg. TK overexpression in the MeHg-exposed mice enhanced generalized anxiety and cue memory in the fear conditioning (FC) test. Early exposure to MeHg induced deficits in reversal spatial memory in the Morris water maze (MWM) test and depression-like behavior in the forced swim test (FST) in only wild-type (WT) mice but did not affect these parameters in TK+ mice. These changes were associated with TK+ effect on the increase in Bdnf 2, 3, 4 and 6 transcription in the hippocampus as well as with interaction of TK+ and MeHg factors for Bdnf 1, 9a and truncated TrkB.T1 transcripts in the prefrontal cortex. However, the MeHg-induced anxiety-like behavior in the elevated plus maze (EPM) and open field (OF) tests was ameliorated by TK+ background only in the OF test. Moreover, TK overexpression in the MeHg mice did not prevent significant stress-induced weight loss during the period of adaptation to individual housing in metabolic cages. These TK genotype-independent changes were primarily accompanied by the MeHg-induced hippocampal deficits in the activity-dependent Bdnf 1, 4 and 9a variants, TrkB.T1, and transcripts for important antioxidant enzymes glyoxalases Glo1 and Glo2 and glutathione reductase Gsr. Our data suggest a role of full-length TrkB in buffering against memory deficits and depression-like behavior in the MeHg mice but propose the involvement of additional pathways, such as the antioxidant system or TrkB.T1 signaling, in stress- or anxiety-related responses induced by developmental MeHg exposure.

Novel mechanistic insights into treadmill exercise based rescue of social defeat-induced anxiety-like behavior and memory impairment in rats

Social defeat (SD) induced stress causes physiological and behavioral deficits in rodents, including depression and anxiety-like behaviors, as well as memory impairment. Anxiolytic and mood elevating effects of physical exercise are also known. However, rescue effect of physical exercise in social defeat-induced anxiety, depression or memory impairment has not been addressed. The role of epigenetic mechanisms that potentially contribute to these rescue or protective effects is also not known. The present study investigated the effect of moderate treadmill exercise on anxiety-like behavior and memory function in rats subjected to SD using a modified version of the resident-intruder model for social stress (defeat). Changes in histone acetylation and histone-modifying enzymes were examined in hippocampus, amygdala and frontal cortex which are considered critical for anxiety, depression and cognition. Sprague Dawley rats were randomly assigned in four groups; control, exercised, social defeat, social defeat and exercise. At the end of the SD or control exposure lasting 30 min daily for 7 days, one group of SD rats was subjected to treadmill exercise for 2 weeks, whereas the other SD group was handled without exercise. Anxiety-like behavior tests and radial arm water maze test suggested that moderate treadmill exercise rescued social defeat induced anxiety-like behavior and memory impairment. Moreover, exercise normalized SD-induced increase in oxidative stress, most likely by adjusting antioxidant response. Our data suggests involvement of epigenetic mechanisms including histone acetylation of H3 and modulation of methyl-CpG-binding in the hippocampus that might contribute to the rescue effects of exercise in SD-induced behavioral deficits in rats.

Novel therapeutic targets in depression and anxiety: antioxidants as a candidate treatment

There is growing evidence that the imbalance between oxidative stress and the antioxidant defense system may be associated with the development neuropsychiatric disorders, such as depression and anxiety. Major depression and anxiety are presently correlated with a lowered total antioxidant state and by an activated oxidative stress (OS) pathway. The classical antidepressants may produce therapeutic effects other than regulation of monoamines by increasing the antioxidant levels and normalizing the damage caused by OS processes. This chapter provides an overview of recent work on oxidative stress markers in the animal models of depression and anxiety, as well as patients with the aforementioned mood disorders. It is well documented that antioxidants can remove the reactive oxygen species (ROS) and reactive nitrogen species (RNS) through scavenging radicals and suppressing the OS pathway, which further protect against neuronal damage caused oxidative or nitrosative stress sources in the brain, hopefully resulting in remission of depression or anxiety symptoms. The functional understanding of the relationship between oxidative stress and depression and anxiety may pave the way for discovery of novel targets for treatment of neuropsychiatric disorders.

Oxidative stress and psychological disorders

Oxidative stress is an imbalance between cellular production of reactive oxygen species and the counteracting antioxidant mechanisms. The brain with its high oxygen consumption and a lipid-rich environment is considered highly susceptible to oxidative stress or redox imbalances. Therefore, the fact that oxidative stress is implicated in several mental disorders including depression, anxiety disorders, schizophrenia and bipolar disorder, is not surprising. Although several elegant studies have established a link between oxidative stress and psychiatric disorders, the causal relationship between oxidative stress and psychiatric diseases is not fully determined. Another critical aspect that needs much attention and effort is our understanding of the association between cellular oxidative stress and emotional stress. This review examines some of the recent discoveries that link oxidative status with anxiety, depression, schizophrenia and bipolar disorder. A discussion of published results and questions that currently exist in the field regarding a causal relationship between oxidative and emotional stress is also provided.

Individual differences in the neurobiology of social stress: implications for depression-cardiovascular disease comorbidity

Stress initiates a cascade of complex neural and peripheral changes that promote healthy adaption to stress, but when unabated, leads to pathology. Fascinating individual differences arise in the ability to cope with a stressor, rendering an individual more or less likely to develop stress-induced pathologies such as depression, anxiety, and cardiovascular disease. In this review we evaluate recent findings that investigate the neural underpinnings of adopting a passive or active coping response during social defeat stress. Because passive coping is associated with vulnerability to stress-related pathologies and active coping confers resiliency, understanding neurobiological adaptations associated with these diverse coping strategies may reveal biomarkers or targets impacting stress susceptibility. The co-occurrence of stress-induced depression and cardiovascular disease is becoming increasingly clear. Therefore this review focuses on the central mechanisms capable of contributing to psychopathology and cardiovascular disease such as corticotropin releasing factor, neuropeptide Y, monoamines, cytokines and oxidative stress. The impetus for this review is to highlight neurobiological systems that warrant further evaluation for their contribution to the pathophysiology of depression-cardiovascular disease comorbidity.

Oxidative imbalance and anxiety disorders

The oxidative imbalance appears to have an important role in anxiety development. Studies in both humans and animals have shown a strong correlation between anxiety and oxidative stress. In humans, for example, the increased malondialdehyde levels and discrepancies in antioxidant enzymes in erythrocytes have been observed. In animals, several studies also show that anxiety-like behavior is related to the oxidative imbalance. Moreover, anxiety-like behavior can be caused by pharmacological-induced oxidative stress. Studies using knockout or overexpression of antioxidant enzymes have shown a relationship between anxiety-like behavior and oxidative stress. Related factors of oxidative stress that could influence anxious behavior are revised, including impaired function of different mitochondrial proteins, inflammatory cytokines, and neurotrophic factors. It has been suggested that a therapy specifically focus in reducing reactive species production may have a beneficial effect in reducing anxiety. However, the neurobiological pathways underlying the effect of oxidative stress on anxiety symptoms are not fully comprehended. The challenge now is to identify the oxidative stress mechanisms likely to be involved in the induction of anxiety symptoms. Understanding these pathways could help to clarify the neurobiology of the anxiety disorder and provide tools for new discovery in therapies and preventive strategies.

Glyoxalase I (Glo1) and its metabolites in vascular disease

Glo1 (glyxoalase I) is a cytosolic protein expressed in all mammalian cells. Its physiological function is the detoxification of MG (methylglyoxal), which is a potent precursor of AGEs (advanced glycation end-products). Although the impact of AGEs on different forms of vascular diseases has been intensively investigated, the evidence for the involvement of Glo1 and MG is still scarce. Recently, several studies have provided significant evidence for Glo1 having a protective effect on microvascular complications in diabetic patients, such as retinopathy and nephropathy. Regarding macrovascular complications, especially atherosclerotic lesions, the impact of Glo1 is even less clear. In the present article, we review the latest findings regarding the role of Glo1 and MG in vascular biology and the pathophysiology of micro- and macro-vascular disease.

Potential antioxidant and anxiolytic effects of (+)-limonene epoxide in mice after marble-burying test

The present study evaluated anxiolytic activity of (+)-limonene epoxide (EL), through the marble burying test (MBT) assay, and the antioxidant potential in vitro and in vivo in mice hippocampus of adult mice subjected to experimental anxiety protocol. For behavioral studies, and in vivo antioxidant analyses, mice were treated orally with 0.05% Tween 80 dissolved in 0.9% saline solution (vehicle), ascorbic acid 250 mg/kg, diazepam (2 mg/kg) and EL (25, 50 and 75 mg/kg). Results suggest an anxiolytic effect of (+)-limonene epoxide. A reduction in number of buried marbles in groups treated with EL doses of 25, 50 and 75 mg/kg was observed when compared with diazepam and vehicle groups. This reduction was observed after treatments with single and repeated doses, reinforcing the hypothesis of anxiolytic effect. The anxiolytic effect was reversed by pretreatment with flumazenil (25 mg/kg, o.r) in the same way as it was observed with diazepam (2 mg/kg, o.r, positive control), suggesting that these drugs possess a similar mechanism of action. In antioxidant tests in vitro, the concentrations from 0.9 to 7.2 μg/ml were tested. The results of in vitro antioxidant tests demonstrated a 50% inhibitory effective concentration of 0.7342, 1.296 and 1.169 μg/ml against the formation of nitrite ion, hydroxyl radical and reactive substances to thiobarbituric acid, respectively. The treatment with EL reduced the lipid peroxidation level and nitrite content, suggesting an antioxidant role in vivo since it was able to reduce the formation of reactive species derived from oxygen and nitrogen. Furthermore, the EL increased activity of enzymes catalase and superoxide dismutase in mice hippocampus, suggesting that their role may be due to antioxidant upregulation of these enzymes.

Associations of serum uric acid and SLC2A9 variant with depressive and anxiety disorders: a population-based study

BACKGROUND

Limited information exists regarding the association between serum uric acid (SUA) and psychiatric disorders. We explored the relationship between SUA and subtypes of major depressive disorder (MDD) and specific anxiety disorders. Additionally, we examined the association of SLC2A9 rs6855911 variant with anxiety disorders.

METHODS

We conducted a cross-sectional analysis on 3,716 individuals aged 35-66 years previously selected for the population-based CoLaus survey and who agreed to undergo further psychiatric evaluation. SUA was measured using uricase-PAP method. The French translation of the semi-structured Diagnostic Interview for Genetic Studies was used to establish lifetime and current diagnoses of depression and anxiety disorders according to the DSM-IV criteria.

RESULTS

Men reported significantly higher levels of SUA compared to women (357±74 µmol/L vs. 263±64 µmol/L). The prevalence of lifetime and current MDD was 44% and 18% respectively while the corresponding estimates for any anxiety disorders were 18% and 10% respectively. A quadratic hockey-stick shaped curve explained the relationship between SUA and social phobia better than a linear trend. However, with regards to the other specific anxiety disorders and other subtypes of MDD, there was no consistent pattern of association. Further analyses using SLC2A9 rs6855911 variant, known to be strongly associated with SUA, supported the quadratic relationship observed between SUA phenotype and social phobia.

CONCLUSIONS

A quadratic relationship between SUA and social phobia was observed consistent with a protective effect of moderately elevated SUA on social phobia, which disappears at higher concentrations. Further studies are needed to confirm our observations.

Depression, anxiety-like behavior and memory impairment are associated with increased oxidative stress and inflammation in a rat model of social stress

In the present study, we have examined the behavioral and biochemical effect of induction of psychological stress using a modified version of the resident-intruder model for social stress (social defeat). At the end of the social defeat protocol, body weights, food and water intake were recorded, depression and anxiety-like behaviors as well as memory function was examined. Biochemical analysis including oxidative stress measurement, inflammatory markers and other molecular parameters, critical to behavioral effects were examined. We observed a significant decrease in the body weight in the socially defeated rats as compared to the controls. Furthermore, social defeat increased anxiety-like behavior and caused memory impairment in rats (P<0.05). Socially defeated rats made significantly more errors in long term memory tests (P<0.05) as compared to control rats. Furthermore, brain extracellular signal-regulated kinase-1/2 (ERK1/2), and an inflammatory marker, interleukin (IL)-6 were activated (P<0.05), while the protein levels of glyoxalase (GLO)-1, glutathione reductase (GSR)-1, calcium/calmodulin-dependent protein kinase type (CAMK)-IV, cAMP-response-element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were significantly less (P<0.05) in the hippocampus, but not in the prefrontal cortex and amygdala of socially defeated rats, when compared to control rats. We suggest that social defeat stress alters ERK1/2, IL-6, GLO1, GSR1, CAMKIV, CREB, and BDNF levels in specific brain areas, leading to oxidative stress-induced anxiety-depression-like behaviors and as well as memory impairment in rats.

A high-salt diet further impairs age-associated declines in cognitive, behavioral, and cardiovascular functions in male Fischer brown Norway rats

Aging-associated declines in cognitive, emotional, and cardiovascular function are well known. Environmental stress triggers critical changes in the brain, further compromising cardiovascular and behavioral health during aging. Excessive dietary salt intake is one such stressor. Here, we tested the effect of high salt (HS) on anxiety, learning-memory function, and blood pressure (BP) in male Fischer brown Norway (FBN) rats. Adult (A; 2 mo) and old (O; 20 mo) male rats were fed normal-salt (NS; 0.4% NaCl) or HS (8% NaCl) diets for 4 wk after being implanted with telemeter probes for conscious BP measurement. Thereafter, tests to assess anxiety-like behavior and learning-memory were conducted. The rats were then killed, and samples of plasma, urine, and brain tissue were collected. We found that systolic BP was higher in O-NS (117 ± 1.2 mm Hg) than in A-NS (105 ± 0.8 mm Hg) rats (P < 0.05). Furthermore, BP was higher in O-HS (124 ± 1.4 mm Hg) than in O-NS (117 ± 1.2 mm Hg) rats (P < 0.05). Moreover, anxiety-like behavior (light-dark and open-field tests) was not different between A-NS and O-NS rats but was greater in O-HS rats than in A-NS, O-NS, or A-HS rats (P < 0.05). Short-term memory (radial arm water maze test) was similar in A-NS and O-NS rats but was significantly impaired in O-HS rats compared with A-NS, O-NS, or A-HS rats (P < 0.05). Furthermore, oxidative stress variables (in plasma, urine, and brain) as well as corticosterone (plasma) were greater in O-HS rats when compared with A-NS, O-NS, or A-HS rats (P < 0.05). The antioxidant enzyme glyoxalase-1 expression was selectively reduced in the hippocampus and amygdala of O-HS rats compared with A-NS, O-NS, or A-HS rats (P < 0.05), whereas other antioxidant enzymes, glutathione reductase 1, manganese superoxide dismutase (SOD), and Cu/Zn SOD remained unchanged. We suggest that salt-sensitive hypertension and behavioral derangement are associated with a redox imbalance in the brain of aged FBN rats.

Grape powder supplementation prevents oxidative stress-induced anxiety-like behavior, memory impairment, and high blood pressure in rats

We examined whether or not grape powder treatment ameliorates oxidative stress-induced anxiety-like behavior, memory impairment, and hypertension in rats. Oxidative stress in Sprague-Dawley rats was produced by using L-buthionine-(S,R)-sulfoximine (BSO). Four groups of rats were used: 1) control (C; injected with vehicle and provided with tap water), 2) grape powder-treated (GP; injected with vehicle and provided for 3 wk with 15 g/L grape powder dissolved in tap water), 3) BSO-treated [injected with BSO (300 mg/kg body weight), i.p. for 7 d and provided with tap water], and 4) BSO plus grape powder-treated (GP+BSO; injected with BSO and provided with grape powder-treated tap water). Anxiety-like behavior was significantly greater in BSO rats compared with C or GP rats (P < 0.05). Grape powder attenuated BSO-induced anxiety-like behavior in GP+BSO rats. BSO rats made significantly more errors in both short- and long-term memory tests compared with C or GP rats (P < 0.05), which was prevented in GP+BSO rats. Systolic and diastolic blood pressure was significantly greater in BSO rats compared with C or GP rats (P < 0.05), whereas grape powder prevented high blood pressure in GP+BSO rats. Furthermore, brain extracellular signal-regulated kinase-1/2 (ERK-1/2) was activated (P < 0.05), whereas levels of glyoxalase-1 (GLO-1), glutathione reductase-1 (GSR-1), calcium/calmodulin-dependent protein kinase type IV (CAMK-IV), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF) were significantly less (P < 0.05) in BSO but not in GP+BSO rats compared with C or GP rats. We suggest that by regulating brain ERK-1/2, GLO-1, GSR-1, CAMK-IV, CREB, and BDNF levels, grape powder prevents oxidative stress-induced anxiety, memory impairment, and hypertension in rats.

How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways

Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.

Neurobiological consequences of sleep deprivation

Although the physiological function of sleep is not completely understood, it is well documented that it contributes significantly to the process of learning and memory. Ample evidence suggests that adequate sleep is essential for fostering connections among neuronal networks for memory consolidation in the hippocampus. Sleep deprivation studies are extremely valuable in understanding why we sleep and what are the consequences of sleep loss. Experimental sleep deprivation in animals allows us to gain insight into the mechanism of sleep at levels not possible to study in human subjects. Many useful approaches have been utilized to evaluate the effect of sleep loss on cognitive function, each with relative advantages and disadvantages. In this review we discuss sleep and the detrimental effects of sleep deprivation mostly in experimental animals. The negative effects of sleep deprivation on various aspects of brain function including learning and memory, synaptic plasticity and the state of cognition-related signaling molecules are discussed.

Is oxidative stress in mice brain regions diminished by 2-[(2,6-dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile?

2-[(2,6-Dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile, 5TIO1, is a new 2-aminothiophene derivative with promising pharmacological activities. The aim of this study was to evaluate its antioxidant activity in different areas of mice central nervous system. Male Swiss adult mice were intraperitoneally treated with Tween 80 dissolved in 0.9% saline (control group) and 5TIO1 (0.1, 1, and 10 mg kg(-1)). Brain homogenates-hippocampus, striatum, frontal cortex, and cerebellum-were obtained after 24 h of observation. Superoxide dismutase and catalase activities, lipid peroxidation and nitrite content were measured using spectrophotometrical methods. To clarify the 5TIO1's mechanism on oxidative stress, western blot analysis of superoxide dismutase and catalase was also performed. 5TIO1 decreased lipid peroxidation and nitrite content in all brain areas and increased the antioxidant enzymatic activities, specially, in cerebellum. The data of Western blot analysis did not demonstrate evidence of the upregulation of these enzymes after the administration of this compound. Our findings strongly support that 5TIO1 can protect the brain against neuronal damages regularly observed during neuropathologies.

Increased error-related brain activity in youth with obsessive-compulsive disorder and other anxiety disorders

The error-related negativity (ERN) is a negative deflection in the event-related potential after an incorrect response that is thought to reflect activity in the anterior cingulate cortex (ACC) and is often increased in patients with anxiety disorders. This study measured the ERN and correct response negativity (CRN) during an Eriksen flanker task to assess performance monitoring in 26 youth with obsessive-compulsive disorder (OCD), 13 youth with a non-OCD anxiety disorder consisting of either generalized anxiety disorder or separation anxiety disorder, and 27 age-matched healthy controls ranging in age from 8 to 16 years. Compared to healthy controls, ERN amplitude was significantly increased in patients with either OCD or a non-OCD anxiety disorder. There were no significant group differences in CRN amplitude. Treatment with a serotonergic antidepressant or cognitive-behavior therapy had no effect on the ERN in patients. Scores from the Child Behavior Checklist DSM-oriented anxiety problems scale had a significant correlation with ERN amplitude in all subjects. The results provide further evidence that the pathophysiology of OCD and some non-OCD anxiety disorders involves increased ACC activity and that the ERN may serve as a quantitative phenotype in genetic and longitudinal studies of these complex traits.

Exercising the worry away: how inflammation, oxidative and nitrogen stress mediates the beneficial effect of physical activity on anxiety disorder symptoms and behaviours

Regular physical activity exerts positive effects on anxiety disorder symptoms, although the biological mechanisms underpinning this effect are incompletely understood. Numerous lines of evidence support inflammation and oxidative and nitrogen stress (O&NS) as important in the pathogenesis of mood and anxiety disorders, and physical activity is known to influence these same pathways. This paper reviews the inter-relationships between anxiety disorders, physical activity and inflammation and O&NS, to explore whether modulation of inflammation and O&NS may in part underpin the positive effect of physical activity on anxiety disorders. Numerous studies support the notion that physical activity operates as an anti-inflammatory and anti-O&NS agent which potentially exerts positive effects on neuroplasticity, the expression of neurotrophins and normal neuronal functions. These effects may therefore influence the expression and evolution of anxiety disorders. Further exploration of this area may elicit a deeper understanding of the pathogenesis of anxiety disorders, and inform the development of integrated programmes including PA specifically suited to the treatment and prevention of anxiety disorders and symptoms.

Role of Glyoxalase 1 (Glo1) and methylglyoxal (MG) in behavior: recent advances and mechanistic insights

Glyoxalase 1 (GLO1) is a ubiquitous cellular enzyme that participates in the detoxification of methylglyoxal (MG), a cytotoxic byproduct of glycolysis that induces protein modification (advanced glycation end-products, AGEs), oxidative stress, and apoptosis. The concentration of MG is elevated under high-glucose conditions, such as diabetes. As such, GLO1 and MG have been implicated in the pathogenesis of diabetic complications. Recently, findings have linked GLO1 to numerous behavioral phenotypes, including psychiatric diseases (anxiety, depression, schizophrenia, and autism) and pain. This review highlights GLO1's association with behavioral phenotypes, describes recent discoveries that have elucidated the underlying mechanisms, and identifies opportunities for future research.

Stress-induced epigenetic regulation of κ-opioid receptor gene involves transcription factor c-Myc

Exposure to stress is associated with adverse emotional and behavioral responses. Whereas the κ-opioid receptor (KOR) system is known to mediate some of the effects, it is unclear whether and how stress affects epigenetic regulation of this gene. Because the KOR gene can use two promoters (Pr1 and Pr2) and two polyadenylation signals (PA1 and PA2), it is also interesting whether and how these distinct regulatory mechanisms are differentially modulated by stress. The current study examined the effects of stress on these different regulatory mechanisms of the KOR gene. Results showed that stress selectively increased the expression of KOR mRNA isoforms controlled by Pr1 and terminated at PA1 in specific brain areas including the medial-prefrontal cortex, hippocampus, brainstem, and sensorimotor cortex, but not in the amygdala or hypothalamus. These effects correlated with altered epigenetic state of KOR Pr1 chromatin, as well as elevation and increased recruitment of the principal transcription factor c-Myc, which could activate Pr1. Stress-induced modulation of Pr1 was further validated using glutamate-sensitive murine hippocampal cell line, HT22. The results revealed a common molecular mechanism underlying the effect of stress on selected chromatin regions of this gene at the cellular level and in the context of whole animal and identified a critical role for c-Myc in stress-triggered epigenetic regulation of the KOR gene locus. This study sheds light on the mechanisms of stress-induced epigenetic regulation that targets specific chromatin segments and suggests certain KOR transcripts and its principal transcription factor c-Myc as potential targets for brain-area-specific intervention.

Late effects of a perinatal exposure to a 16 PAH mixture: Increase of anxiety-related behaviours and decrease of regional brain metabolism in adult male rats

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous pollutants originated from incomplete combustion processes. Ingestion of contaminated food is the main route of exposure for humans. These molecules are able to cross the placental barrier and are also found in breast milk. Since PAHs are neurotoxic agents, the potential adverse effects of a perinatal exposure of the developing brain is a key issue for public health especially concerning PAH mixture. In this study, female rats were exposed trough diet to a mixture of 16 PAHs, at doses of 2 μg/kg/day or 200 μg/kg/day during gestation and 1.5 μg/kg/day or 150 μg/kg/day during breast-feeding period. To assess late neurotoxic effects in male offsprings, behavioural and cognitive tests were carried out and histochemical analyses using cytochrome oxidase as a cerebral metabolism marker were performed on adult animals. Results showed that anxiety-related behaviours significantly increased in exposed animals, but there was no significant alteration of motor activity and learning and memory abilities. Several brain areas of the limbic system showed a neuronal hypometabolism in exposed animals. This work highlights that exposure to PAHs at early stages of brain development can cause later troubles on behaviour and that PAHs are able to partly alter the central nervous system metabolism on adulthood.

The neuroprotective effect of vitamin E on chronic sleep deprivation-induced memory impairment: the role of oxidative stress

Sleep deprivation induces oxidative stress and impairs learning and memory processes. Vitamin E, on the other hand, is a strong antioxidant that has neuroprotective effect on the brain. In this study, we examined the potential protective effect of chronic administration of vitamin E on chronic sleep deprivation-induced cognitive impairment. In addition, possible molecular targets for vitamin E effects on chronic sleep deprivation-induced cognitive impairment were determined. Sleep deprivation was induced in rats using modified multiple platform model. Vitamin E (100mg/kg) was administered to animals by oral gavage. Behavioral study was conducted to test the spatial learning and memory using the radial arm water maze (RAWM). In addition, the hippocampus was dissected out and antioxidant markers including glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG, glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD) were assessed. The results of this project revealed that chronic sleep deprivation impaired both (short- and long-term) memories (P<0.05), while vitamin E treatment prevented such effect. Additionally, vitamin E normalized chronic sleep deprivation-induced reduction in the hippocampus GSH/GSSG ratio, and activity of catalase, SOD, and GPx. In conclusion, sleep deprivation induces memory impairment, and treatment with vitamin E prevented this impairment probably through its antioxidant action in the hippocampus.