COVID-19, Anxiety, and Body Mass Index Increase Leptin Levels: a Cross-sectional Multicentric Study

Although many efforts have been made to understand the pathophysiological mechanisms of COVID-19, critical gaps remain to be explored. This study aimed to investigate potential alterations in adipokine levels (specifically adiponectin, leptin, and resistin) among individuals with COVID-19. Within this population, we further assessed the association between these markers with both, body mass index (BMI) and psychiatric symptoms. This cross-sectional study included an age- and sex-matched sample of adults with COVID-19 (cases) and without COVID-19 (controls). We evaluated the severity of psychiatric symptoms, BMI, and adipokines. Individuals with COVID-19 presented greater BMI, stress levels, and leptin levels when compared to controls. Leptin levels were greater in individuals with moderate/severe COVID-19 as compared to individuals with COVID-19 who were asymptomatic or having mild symptoms. Leptin levels were positively correlated with BMI, severity of depressive and anxiety symptoms, and stress levels in the total sample. Leptin levels were also positively correlated with BMI, severity of anxiety symptoms, and stress levels in controls. In cases, there was a positive correlation between adiponectin and the severity of depressive symptoms and stress levels and leptin/resistin with BMI. A linear regression model revealed that BMI, severity of anxiety symptoms, and the diagnosis of COVID-19 are independently associated with increased leptin levels. Thus, leptin levels seem to be impacted by the COVID-19 infection, anxiety, and BMI.

Environmental Enrichment Rescues Oxidative Stress and Behavioral Impairments Induced by Maternal Care Deprivation: Sex- and Developmental-Dependent Differences

Stress is related to major depressive disorder (MDD). This study investigated the action that early stress, represented by maternal deprivation (MD), has on the behavior and oxidative stress of Wistar female and male rats. Also, it was evaluated whether changes induced by MD could be reversed by environmental enrichment (EE). Male and female rats were divided into a non-MD and MD group. The MD group was subdivided into 3 groups: (1) assessed on the 31st day after exposure to EE for 10 days, (2) assessed on the 41st day after exposure to EE for 20 days, and (3) assessed on the 61st day after exposure to EE for 40 days. Behavioral tests were performed (memory habituation and elevated plus maze). Oxidative stress parameters were evaluated peripherally. MD was able to promote anxiety-like behavior at postnatal day (PND) 41 and impair memory at PND 31 and PND 61 in male and PND 41 and PND 61 in female rats. MD was associated with increased oxidative stress parameters (reactive species to thiobarbituric acid levels (TBARS), carbonylated proteins, nitrite/nitrate concentration), and altered antioxidant defenses (superoxide dismutase (SOD) and catalase (CAT), and sulfhydryl content) in different stages of development. The EE was able to reverse almost all behavioral and biochemical changes induced by MD; however, EE effects were sex and developmental period dependent. These findings reinforce the understanding of the gender variable as a biological factor in MDD related to MD and EE could be considered a treatment option for MDD treatment and its comorbidities.

ABO Blood Type and Metabolic Markers in COVID-19 Susceptibility and Severity: A Cross-Sectional Study

Background and Aims: To evaluate the effect of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus on the function and metabolic changes, as well as the relationship of the virus with blood groups. Methods and Results: This cross-sectional study included a matched sample of adult individuals with coronavirus disease 2019 (COVID-19) (n = 114) or without (controls; n = 236). Blood samples were collected and processed for triglycerides (TGs), total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and blood typing analysis. The results showed that subjects with COVID-19 had higher TG and lower HDL-C levels compared with the control group. As for blood typing, the risk of COVID-19 was higher in subjects with blood group A than in those with blood group B and in those with other blood groups. In addition, an association of COVID-19 with blood type and Rh A- was observed. When related to the severity of COVID-19 symptoms, blood type A was more protective against moderate/severe symptoms compared with blood type O. In addition, individuals with blood type O were 2.90 times more likely to have symptoms moderate/severe symptoms of COVID-19 than those with other blood groups and individuals with type A blood were less likely to have severe/moderate symptoms of COVID-19 compared with individuals without type A blood. Conclusion: The results suggest that blood type may play a role in susceptibility to SARS-CoV-2 infection and add evidence that infection with the novel coronavirus may be associated with changes in lipid metabolism.

Stress levels, psychological symptoms, and C-reactive protein levels in COVID-19: A cross-sectional study

BACKGROUND

Although many studies have pointed out a possible relationship between COVID-19 and the presence of psychiatric disorders, the majority of the studies have significant limitations. This study investigates the influence of COVID-19 infection on mental health.

METHODS

This cross-sectional study included an age- and sex-matched sample of adult individuals positive (cases) or negative (controls) for COVID-19. We evaluated the presence of psychiatric conditions and C-reactive protein (CRP).

RESULTS

Findings showed greater severity of depressive symptoms, higher levels of stress, and greater CRP in cases. The severity of depressive and insomnia symptoms, as well as the CRP were more remarkable in individuals with moderate/severe COVID-19. We found a positive correlation between stress and severity of anxiety, depression, and insomnia in individuals with or without COVID-19. There was a positive correlation between CRP levels and severity of depressive symptoms in cases and controls, and a positive correlation between CRP levels and the severity of anxiety symptoms and stress levels only in individuals with COVID-19. Individuals with COVID-19 and depression had greater CRP than those with COVID-19 without current major depressive disorder.

LIMITATIONS

We cannot infer causality because this is a cross-sectional study, and the majority of COVID-19 sample was asymptomatic or had mild symptoms, which may limit the generalizability of our findings for moderate/severe cases.

CONCLUSIONS

Individuals with COVID-19 showed greater severity of psychological symptoms, which may impact on the development of psychiatric disorders in the future. CPR seem to be a promising biomarker for earlier detection of post-COVID depression.

Natural Phytochemicals for the Treatment of Major Depressive Disorder: A Mini-Review of Pre- and Clinical Studies

Major Depressive Disorder (MDD) is a common mental illness that causes significant disability and declining quality of life. An overlap of multiple factors can be involved in the pathophysiology of this mood disorder, including increased inflammation and oxidative stress, change in neurotransmitters, decreased brain-derived neurotrophic factor (BDNF), activation of the hypothalamicpituitary- adrenal (HPA) axis, and changes in the microbiota-gut-brain axis. Although the classic treatment for MDD is safe, it is far from ideal, with delay to start the best clinic, side effects, and a large number of non-responses or partial-responses. Therefore, other alternatives are being studied to improve depressive symptoms, and, among them, the role of phytochemicals in food stands out. This mini-review will discuss the main phytochemicals present in foods with clinical and preclinical studies showing benefits for MDD treatment. In addition, the main mechanisms of action that are being proposed for each of these compounds will be addressed.

Sex differences on the response to antidepressants and psychobiotics following early life stress in rats

Major depressive disorder (MDD) is the most prevalent mood disorder globally. Most antidepressants available for the treatment of MDD increase the concentration of monoamines in the synaptic cleft. However, such drugs have a high latency time to obtain benefits. Thus, new antidepressants with fast action and robust efficacy are very important. This study evaluated the effects of escitalopram, ketamine, and probiotic Bifidobacterium infantis in rats submitted to the maternal deprivation (MD). MD rats received saline, escitalopram, ketamine, or probiotic for 10, 30, or 50 days, depending on the postnatal day (PND):21, 41, and 61. Following behavior, this study examined the integrity of the blood-brain barrier (BBB) and oxidative stress markers. MD induced depressive-like behavior in females with PND21 and males with PND61. All treatments reversed depressive-like behavior in females and escitalopram and ketamine in males. MD induced an increase in the permeability of the BBB, an imbalance between oxidative stress and antioxidant defenses. Treatments regulated the oxidative damage and the integrity of the BBB induced by MD. The treatment with escitalopram, ketamine, or probiotics may prevent behavioral and neurochemical changes associated with MDD, depending on the developmental period and gender.

Microbiota-Gut-Brain Communication in the SARS-CoV-2 Infection

The coronavirus disease of 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome 2 (SARS-CoV-2). In addition to pneumonia, individuals affected by the disease have neurological symptoms. Indeed, SARS-CoV-2 has a neuroinvasive capacity. It is known that the infection caused by SARS-CoV-2 leads to a cytokine storm. An exacerbated inflammatory state can lead to the blood-brain barrier (BBB) damage as well as to intestinal dysbiosis. These changes, in turn, are associated with microglial activation and reactivity of astrocytes that can promote the degeneration of neurons and be associated with the development of psychiatric disorders and neurodegenerative diseases. Studies also have been shown that SARS-CoV-2 alters the composition and functional activity of the gut microbiota. The microbiota-gut-brain axis provides a bidirectional homeostatic communication pathway. Thus, this review focuses on studies that show the relationship between inflammation and the gut microbiota-brain axis in SARS-CoV-2 infection.

Environmental enrichment improves lifelong persistent behavioral and epigenetic changes induced by early-life stress

This study aimed to evaluate the effects of environmental enrichment (EE) in Wistar rats subjected to maternal deprivation (MD). MD was performed in the first post-natal days (PND) ten for 3 h/day. The groups were: control; deprived without EE; and deprived with EE. The EE was applied for 3 h/day. Forced swimming test (FST) and open field test were performed, and histone deacetylase (HDAC) and DNA methyltransferase (DNMT) activities in the prefrontal cortex (PFC) and hippocampus were evaluated on 31, 41, and 61 PND. MD altered spontaneous locomotor activity and immobility time in FST, but the effects were sex- and developmental period dependent. In deprived females at PND 31, 41, and 61, HDAC and DNMT increased in the PFC and hippocampus. In females exposed to EE for 20 days, there was a decrease of HDAC in the hippocampus and DNMT in the PFC and hippocampus. Exposure of females to EE for 40 days can reverse HDAC and DNMT increase in all brain areas. In deprived males at PND 31, 41, and 61, HDAC and DNMT increased in the hippocampus, and in the group exposed to EE for 40 days, there was a decrease in hippocampal activity. In PFC of male deprived rats at PND 61 and EE for 40 days, there was a reduction of HDAC and DNMT. MD induced lifelong persistent behavioral and epigenetic changes, and such effects were more evident in female than male rats. EE can be considered an essential non-pharmacological strategy to treat long-term trauma-induced early life changes.

Hypericum perforatum chronic treatment affects cognitive parameters and brain neurotrophic factor levels

Objective:

To evaluate the effects of Hypericum perforatum (hypericum) on cognitive behavior and neurotrophic factor levels in the brain of male and female rats.

Methods:

Male and female Wistar rats were treated with hypericum or water during 28 days by gavage. The animals were then subjected to the open-field test, novel object recognition and step-down inhibitory avoidance test. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial cell-line derived neurotrophic factor (GDNF) levels were evaluated in the hippocampus and frontal cortex.

Results:

Hypericum impaired the acquisition of short- and long-term aversive memory in male rats, evaluated in the inhibitory avoidance test. Female rats had no immediate memory acquisition and decreased short-term memory acquisition in the inhibitory avoidance test. Hypericum also decreased the recognition index of male rats in the object recognition test. Female rats did not recognize the new object in either the short-term or the long-term memory tasks. Hypericum decreased BDNF in the hippocampus of male and female rats. Hypericum also decreased NGF in the hippocampus of female rats.

Conclusions:

The long-term administration of hypericum appears to cause significant cognitive impairment in rats, possibly through a reduction in the levels of neurotrophic factors. This effect was more expressive in females than in males.

Omega-3 fatty acids and mood stabilizers alter behavioral and oxidative stress parameters in animals subjected to fenproporex administration

Studies have shown that oxidative stress is involved in the pathophysiology of bipolar disorder (BD). It is suggested that omega-3 (ω3) fatty acids are fundamental to maintaining the functional integrity of the central nervous system. The animal model used in this study displayed fenproporex-induced hyperactivity, a symptom similar to manic BD. Our results showed that the administration of fenproporex, in the prevent treatment protocol, increased lipid peroxidation in the prefrontal cortex (143%), hippocampus (58%) and striatum (181%), and ω3 fatty acids alone prevented this change in the prefrontal cortex and hippocampus, whereas the co-administration of ω3 fatty acids with VPA prevented the lipoperoxidation in all analyzed brain areas, and the co-administration of ω3 fatty acids with Li prevented this increase only in the prefrontal cortex and striatum. Moreover, superoxide dismutase (SOD) activity was decreased in the striatum (54%) in the prevention treatment, and the administration of ω3 fatty acids alone or in combination with Li and VPA partially prevented this inhibition. On the other hand, in the reversal treatment protocol, the administration of fenproporex increased carbonyl content in the prefrontal cortex (25%), hippocampus (114%) and striatum (91%), and in prefrontal coxter the administration of ω3 fatty acids alone or in combination with Li and VPA reversed this change, whereas in the hippocampus and striatum only ω3 fatty acids alone or in combination with VPA reversed this effect. Additionally, the administration of fenproporex resulted in a marked increase of TBARS in the hippocampus and striatum, and ω3 fatty acids alone or in combination with Li and VPA reversed this change. Finally, fenproporex administration decreased SOD activity in the prefrontal cortex (85%), hippocampus (52%) and striatum (76%), and the ω3 fatty acids in combination with VPA reversed this change in the prefrontal cortex and striatum, while the co-administration of ω3 fatty acids with Li reversed this inhibition in the hippocampus and striatum. In conclusion, our results support other studies showing the importance of ω3 fatty acids in the brain and the potential for these fatty acids to aid in the treatment of BD.

The Effects of Histone Deacetylase Inhibition on the Levels of Cerebral Cytokines in an Animal Model of Mania Induced by Dextroamphetamine

Studies have suggested the involvement of inflammatory processes in the physiopathology of bipolar disorder. Preclinical evidences have shown that histone deacetylase inhibitors may act as mood-stabilizing agents and protect the brain in models of mania and depression. The aim of the present study was to evaluate the effects of sodium butyrate (SB) and valproate (VPA) on behavioral changes, histone deacetylase activity, and the levels of cytokines in an animal model of mania induced by dextroamphetamine (d-AMPH). Wistar rats were first given d-AMPH or saline (Sal) for a period of 14 days, and then, between the 8th and 14th days, the rats were treated with SB, VPA, or Sal. The activity of histone deacetylase and the levels of cytokines (interleukin (IL) IL-4, IL-6, and IL-10 and tumor necrosis factor-alpha (TNF-α)) were evaluated in the frontal cortex and striatum of the rats. The administration of d-AMPH increased the activity of histone deacetylase in the frontal cortex. Administration of SB or VPA decreased the levels of histone deacetylase activity in the frontal cortex and striatum of rats. SB per se increased the levels of cytokines in both of the brain structures evaluated. AMPH increased the levels of cytokines in both of the brain structures evaluated, and VPA reversed this alteration. The effects of SB on d-AMPH-induced cytokine alterations were dependent on the brain structure and the cytokine evaluated. Despite VPA and SB having a similar mechanism of action, both being histone deacetylase inhibitors, they showed different effects on the levels of cytokines. The present study reinforces the need for more research into histone deacetylase inhibitors being used as a possible target for new medications in the treatment of bipolar disorder.

Omega-3 Fatty Acids and Mood Stabilizers Alter Behavioural and Energy Metabolism Parameters in Animals Subjected to an Animal Model of Mania Induced by Fenproporex

Studies have shown that changes in energy metabolism are involved in the pathophysiology of bipolar disorder (BD). It was suggested that omega-3 (ω3) fatty acids have beneficial properties in the central nervous system and that this fatty acid plays an important role in energy metabolism. Therefore, the study aimed to evaluate the effect of ω3 fatty acids alone and in combination with lithium (Li) or valproate (VPA) on behaviour and parameters of energy metabolism in an animal model of mania induced by fenproporex. Our results showed that co-administration of ω3 fatty acids and Li was able to prevent and reverse the increase in locomotor and exploratory activity induced by fenproporex. The combination of ω3 fatty acids with VPA was only able to prevent the fenproporex-induced hyperactivity. For the energy metabolism parameters, our results showed that the administration of Fen for the reversal or prevention protocol inhibited the activities of succinate dehydrogenase, complex II and complex IV in the hippocampus. However, hippocampal creatine kinase (CK) activity was decreased only for the reversal protocol. The ω3 fatty acids, alone and in combination with VPA or Li, prevented and reversed the decrease in complex II, IV and succinate dehydrogenase activity, whereas the decrease in CK activity was only reversed after the co-administration of ω3 fatty acids and VPA. In conclusion, our results showed that the ω3 fatty acids combined with VPA or Li were able to prevent and reverse manic-like hyperactivity and the inhibition of energy metabolism in the hippocampus, suggesting that ω3 fatty acids may play an important role in the modulation of behavioural parameters and energy metabolism.

Prevalência de transtornos ansiosos e algumas comorbidades em idosos: um estudo de base populacional

RESUMO Objetivo Avaliar a prevalência de transtornos ansiosos e fatores associados em uma amostra populacional de idosos do Sul de Santa Catarina. Métodos Estudo transversal com base em dados populacionais, que avaliou 1.021 indivíduos idosos entre 60 e 79 anos. Foram realizadas entrevistas domiciliares para aferição de variáveis sobre transtornos ansiosos, por meio do questionário MINI, dados sociodemográficos, hipertensão arterial sistêmica (HAS), infarto agudo do miocárdio (IAM) e dosagem de colesterol. Resultados As prevalências entre os transtornos ansiosos foram de 22,0% para o transtorno de ansiedade generalizada (TAG); 14,8% para fobia social (FS); 10,5% para transtorno do pânico (TP); e 8,5% para o transtorno obsessivo-compulsivo (TOC). Além disso, 40,5% dos indivíduos apresentaram pelo menos um transtorno de ansiedade. A distribuição dos transtornos foi semelhante nos dois gêneros; TAG foi mais prevalente nos indivíduos de menor escolaridade; TOC foi mais presente em indivíduos casados ou em união estável. Em relação às variáveis clínicas, HAS foi associada à presença de TOC; FS foi associada com IAM; TOC e FS foram associados com HDL > 40 mg/dL. Conclusão Os dados demonstram que os quadros de ansiedade são muito frequentes em idosos da comunidade, se sobrepõem de forma significativa e estão associados a algumas variáveis clínicas cardiovasculares.

Sodium butyrate has an antimanic effect and protects the brain against oxidative stress in an animal model of mania induced by ouabain

Studies have consistently reported the participation of oxidative stress in bipolar disorder (BD). Evidence indicates that epigenetic regulations have been implicated in the pathophysiology of mood disorders. Considering these evidences, the present study aimed to investigate the effects of sodium butyrate (SB), a histone deacetylase (HDAC)inhibitor, on manic-like behavior and oxidative stress parameters (TBARS and protein carbonyl content and SOD and CAT activities) in frontal cortex and hippocampus of rats subjected to the animal model of mania induced by intracerebroventricular (ICV) ouabain administration.The results showed that SB reversed ouabain-induced hyperactivity, which represents a manic-like behavior in rats. In addition, the ouabain ICV administration induced oxidative damage to lipid and protein and alters antioxidant enzymes activity in all brain structures analyzed. The treatment with SB was able to reversesboth behavioral and oxidative stress parameters alteration induced by ouabain.In conclusion, we suggest that SB can be considered a potential new mood stabilizer by acts on manic-like behavior and regulatesthe antioxidant enzyme activities, protecting the brain against oxidative damage.

Enriched Flavonoid Fraction from Cecropia pachystachya Trécul Leaves Exerts Antidepressant-like Behavior and Protects Brain Against Oxidative Stress in Rats Subjected to Chronic Mild Stress

The purpose of this study was to assess the effect of an enriched C-glycosyl flavonoids fraction (EFF-Cp) from Cecropia Pachystachya leaves on behavior, mitochondrial chain function, and oxidative balance in the brain of rats subjected to chronic mild stress. Male Wistar rats were divided into experimental groups (saline/no stress, saline/stress, EFF-Cp/no stress, and EFF-Cp/stress). ECM groups were submitted to stress for 40 days. On the 35th ECM day, EFF-Cp (50 mg/kg) or saline was administrated and the treatments lasted until the 42nd day. On the 41st and 42nd days, the animals were submitted to the splash test and the forced swim test. After these behavioral tests, the enzymatic activity of mitochondrial chain complexes and oxidative stress were analyzed. EFF-Cp reversed the depressive-like behavior induced by ECM. It also reversed the increase in thiobarbituric acid reactive species, myeloperoxidase activity, and nitrite/nitrate concentrations in some brain regions. The reduced activities of the antioxidants superoxide dismutase and catalase in some brain regions were also reversed by EFF-Cp. The most pronounced effect of EFF-Cp on mitochondrial complexes was an increase in complex IV activity in all studied regions. Thus, it is can be concluded that EFF-Cp exerts an antidepressant-like effect and that oxidative balance may be an important physiological process underlying these effects.

New perspectives on the involvement of mTOR in depression as well as in the action of antidepressant drugs

Despite the revolution in recent decades regarding monoamine involvement in the management of major depressive disorder (MDD), the biological mechanisms underlying this psychiatric disorder are still poorly understood. Currently available treatments require long time courses to establish antidepressant response and a significant percentage of people are refractory to single drug or combination drug treatment. These issues, and recent findings demonstrating the involvement of synaptic plasticity in the pathophysiological mechanisms of MDD, are encouraging researchers to explore the molecular mechanisms underlying psychiatric disease in more depth. The discovery of the rapid antidepressant effect exerted by glutamatergic and cholinergic agents highlights the mammalian target of rapamycin (mTOR) pathway as a critical pathway that contributes to the efficacy of these pharmacological agents in clinical and pre-clinical research. The mTOR pathway is a downstream intracellular signal that transmits information after the direct activation of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) and neurotrophic factor receptors. Activation of these receptors is hypothesized to be one of the major axes involved in the synthesis of synaptogenic proteins underlying synaptic plasticity and critical to both the rapid and delayed effects exerted by classic antidepressants. This review focuses on the involvement of mTOR in the pathophysiology of depression and on molecular mechanisms involved in the activity of emerging and classic antidepressant agents.

The effects of n-acetylcysteine and/or deferoxamine on manic-like behavior and brain oxidative damage in mice submitted to the paradoxal sleep deprivation model of mania

Bipolar disorder (BD) is a severe psychiatric disorder associated with social and functional impairment. Some studies have strongly suggested the involvement of oxidative stress in the pathophysiology of BD. Paradoxal sleep deprivation (PSD) in mice has been considered a good animal model of mania because it induces similar manic-like behavior, as well as producing the neurochemical alterations which have been observed in bipolar patients. Thus, the objective of the present study was to evaluate the effects of the antioxidant agent's n-acetylcysteine (Nac) and/or deferoxamine (DFX) on behavior and the oxidative stress parameters in the brains of mice submitted to the animal model of mania induced by PSD. The mice were treated for a period of seven days with saline solution (SAL), Nac, DFX or Nac plus DFX. The animals were subject to the PSD protocol for 36 h. Locomotor activity was then evaluated using the open-field test, and the oxidative stress parameters were subsequently evaluated in the hippocampus and frontal cortex of mice. The results showed PSD induced hyperactivity in mice, which is considered a manic-like behavior. In addition to this, PSD increased lipid peroxidation and oxidative damage to proteins, as well as causing alterations to antioxidant enzymes in the frontal cortex and hippocampus of mice. The Nac plus DFX adjunctive treatment prevented both the manic-like behavior and oxidative damage induced by PSD. Improving our understanding relating to oxidative damage in biomolecules, and the antioxidant mechanisms presented in the animal models of mania are important in helping to improve our knowledge concerning the pathophysiology and development of new therapeutical treatments for BD.

Evaluation of acetylcholinesterase in an animal model of mania induced by D-amphetamine

The present study aims to investigate the effects of mood stabilizers, lithium (Li) and valproate (VPA), on acetylcholinesterase (AChE) activity in the brains of rats subjected to an animal model of mania induced by D-amphetamine (D-AMPH). In the reversal treatment, Wistar rats were first given D-AMPH or saline (Sal) for 14 days. Between days 8 and 14, the rats were treated with Li, VPA, or Sal. In the prevention treatment, rats were pretreated with Li, VPA, or Sal. AChE activity was measured in the brain structures (prefrontal cortex, hippocampus, and striatum). Li, alone in reversion and prevention treatments, increased AChE activity in the brains of rats. VPA, alone in prevention treatment, increased AChE activity in all brain regions evaluated; in the reversion, only in the prefrontal. However, D-AMPH decreased activity of AChE in the striatum of rats in both the reversion and prevention treatments. VPA was able to revert and prevent this AChE activity alteration in the rat striatum. Our findings further support the notion that the mechanisms of mood stabilizers also involve changes in AChE activity, thus reinforcing the need for more studies to better characterize the role of acetylcholine in bipolar disorder.

Lithium and tamoxifen modulate cellular plasticity cascades in animal model of mania

Lithium (Li) is the main mood stabilizer and acts on multiple biochemical targets, leading to neuronal plasticity. Several clinical studies have shown that tamoxifen (TMX) - a protein kinase C (PKC) inhibitor - has been effective in treating acute mania. The present study aims to evaluate the effects of TMX on biochemical targets of Li, such as glycogen synthase kinase-3β (GSK-3β), PKC, PKA, CREB, BDNF and NGF, in the brain of rats subjected to an animal model of mania induced by d-amphetamine (d-AMPH). Wistar rats were treated with d-AMPH (2mg/kg, once a day) or saline (Sal; NaCl 0.9%, w/v), Li (47.5 mg/kg, intraperitoneally (i.p.), twice a day) or TMX (1 mg/kg i.p., twice a day) or Sal in protocols of reversion and prevention treatment. Locomotor behavior was assessed using the open-field task, and protein levels were measured by immunoblot. Li and TMX reversed and prevented d-AMPH-induced hyperactivity. Western blot showed that d-AMPH significantly increased GSK-3 and PKC levels, and decreased pGSK-3, PKA, NGF, BDNF and CREB levels in the structures analyzed. Li and TMX were able to prevent and reverse these changes induced by d-AMPH in most structures evaluated. The present study demonstrated that the PKC inhibitor modulates the alterations in the behavior, neurotrophic and apoptosis pathway induced by d-AMPH, reinforcing the need for more studies of PKC as a possible target for treatment of bipolar disorder.

Synergist effects of n-acetylcysteine and deferoxamine treatment on behavioral and oxidative parameters induced by chronic mild stress in rats

A growing body of evidence has pointed to a relationship between oxidative stress and depression. Thus, the present study was aimed at evaluating the effects of the antioxidants n-acetylcysteine (NAC), deferoxamine (DFX) or their combination on sweet food consumption and oxidative stress parameters in rats submitted to 40days of exposure to chronic mild stress (CMS). Our results showed that in stressed rats treated with saline, there was a decrease in sweet food intake and treatment with NAC or NAC in combination with DFX reversed this effect. Treatment with NAC and DFX decreased the oxidative damage, which include superoxide and TBARS production in submitochondrial particles, and also thiobarbituric acid reactive substances (TBARS) levels and carbonyl proteins in the prefrontal cortex, amygdala and hippocampus. Treatment with NAC and DFX also increased the activity of the antioxidant enzymes, superoxide dismutase and catalase in the same brain areas. Even so, a combined treatment with NAC and DFX produced a stronger increase of antioxidant activities in the prefrontal cortex, amygdala and hippocampus. The results described here indicate that co-administration may induce a more pronounced antidepressant activity than each treatment alone. In conclusion, these results suggests that treatment with NAC or DFX alone or in combination on oxidative stress parameters could have positive effects against neuronal damage caused by oxidative stress in major depressive disorders.

Effects of mood stabilizers on hippocampus and amygdala BDNF levels in an animal model of mania induced by ouabain

There is a body of evidence suggesting that BDNF is involved in bipolar disorder (BD) pathogenesis. Intracerebroventricular (ICV) injection of ouabain (OUA), a specific Na(+)/K(+) ATPase inhibitor, induces hyperlocomotion in rats, and has been used as an animal model of mania. The present study aims to investigate the effects of the lithium (Li) and valproate (VPT) in an animal model of mania induced by ouabain. In the reversal model, animals received a single ICV injection of OUA or cerebrospinal fluid (aCSF). From the day following the ICV injection, the rats were treated for 6 days with intraperitoneal (IP) injections of saline (SAL), Li or VPT twice a day. In the maintenance treatment (prevention model), the rats received IP injections of Li, VPT, or SAL twice a day for 12 days. In the 7th day of treatment the animals received a single ICV injection of either OUA or aCSF. After the ICV injection, the treatment with the mood stabilizers continued for more 6 days. Locomotor activity was measured using the open-field test and BDNF levels were measured in rat hippocampus and amygdala by sandwich-ELISA. Li and VPT reversed OUA-related hyperactive behavior in the open-field test in both experiments. OUA decreased BDNF levels in first and second experiments in hippocampus and amygdala and Li treatment, but not VPT reversed and prevented the impairment in BDNF expression after OUA administration in these cerebral areas. Our results suggest that the present model fulfills adequate face, construct and predictive validity as an animal model of mania.

DNA damage after intracerebroventricular injection of ouabain in rats

There is an emerging body of data suggesting that bipolar disorder is associated with DNA damage. Intracerebroventricular (i.c.v.) administration of ouabain in rats results in manic-like alterations. We evaluated DNA damage of peripheral blood, cerebrospinal fluid and hippocampus of rats after i.c.v. ouabain injection. Ouabain-induced hyperlocomotion was examined in an open field. Additionally, we used single cell gel electrophoresis (comet assay) to measure early transient damage in cerebrospinal fluid (CSF), hippocampus and blood; and the micronucleus test to measure persistent damage in total blood samples of rats after ouabain administration. Our findings demonstrated that ouabain induced hyperlocomotion in rats, and this response remained up to 7 days following a single i.c.v. injection. In addition, we observed that the persistent increase in the rat spontaneous locomotion is associated with increased hippocampal and peripheral index of early DNA damage in rats. No significant alterations were observed in the micronucleus frequency in total blood samples of the rats after the ouabain i.c.v. injection. These results suggest that ouabain may induce peripheral and central early DNA damage, but this early damage may be repaired.