Long-term decrease in immediate early gene expression after electroconvulsive seizures.

Electroconvulsive therapy (ECT) is a well-established psychiatric treatment for severe depression. Despite its clinical utility, post-ECT memory deficits are a common side effect. Neuronal plasticity and memory consolidation are intimately related to the expression of immediate early genes (IEG), such as Egr1, Fos and Arc. Changes in IEG activation have been postulated to underlie long-term neuronal adaptations following electroconvulsive seizures (ECS), an animal model of ECT. To test this hypothesis, we used real-time PCR to examine the effect of acute and chronic ECS (8 sessions, one every other day) on the long-term (>24 h) expression of IEG Egr1, Fos and Arc in the hippocampus, a brain region implicated both in the pathophysiology of depression as well as in memory function. We observed a transient increase in Egr1 and Fos expression immediately after ECS, followed by a long-term decrease of IEG levels after both acute and chronic ECS. A separate group of animals, submitted to the same chronic ECS protocol and then subjected to open field or passive avoidance tasks, confirmed robust memory deficits 2 weeks after the last chronic ECS. The possible role of IEG downregulation on long-term learning deficits observed following ECS are discussed.

Time-dependent behavioral recovery after pneumococcal meningitis in rats.

Alterations in hippocampus frequently occur following bacterial meningitis, despite antibiotic treatment. We investigated the cognitive performance in rats submitted to bacterial meningitis after 10, 30, and 60 days. To this aim, we utilized male Wistar rats submitted to either sham (control) or meningitis by Streptococcus pneumoniae, and followed by the initiation of the antibiotic treatment at 16 h after inoculation. The animals underwent six behavioral tasks 10, 30 and 60 days after surgery. We demonstrated that some of the learning and memory impairment, demonstrated 10 days after the induction of meningitis, persists up to 30 days, but not 60 days after induction.

Oxidative stress in brain according to traumatic brain injury intensity.

BACKGROUND: The mechanisms of brain damage and neuroplasticity following traumatic brain injury (TBI) are complex and not completely understood. Thus, we investigated markers of oxidative stress in the central nervous system after mild and severe TBI in rats. MATERIAL AND METHODS: Adult male wistar rats (five animals per group) submitted to mild (mTBI group) or severe TBI (sTBI Group) were sacrificed 30 min, 3, 6, or 12 h after the injury to quantify markers of oxidative damage in different brain regions. Levels of thiobarbituric acid reactive species and protein carbonyl in the cortex, hippocampus, striatum, and cerebellum of mTBI and sTBI groups were compared with the control group. RESULTS: After mTBI, levels of protein oxidation were increased in all analyzed structures in several different times after injury. The increase in TBARS levels was not so consistent in mTBI. In contrast, sTBI did not induce a sustainable increase in oxidative damage markers in all analyzed structures. CONCLUSIONS: Oxidative damage seemed to be inversely proportional to severity of traumatic brain injury.

Peripheral nucleotide hydrolysis in rats submitted to a model of electroconvulsive therapy.

Electroconvulsive therapy (ECT) is an efficacious and safe method for the treatment of mood disorders. Its utilization is accompanied by a myriad of biochemical and cellular changes, which are far from fully understood. The present work investigates in rat serum the effects of seizures induced by electroconvulsive shocks (ECS), an animal model of ECT, on enzymes that hydrolyze ATP, ADP and AMP to adenosine. Two different models of ECS were used, consisting in the application of one or eight ECS sessions, and respectively named acute or chronic. Serum samples were collected at several time points after the single shock in the acute and after the eighth and last shock in the chronic model. A single shock produced a sudden and short-lived inhibition of enzymatic activity (P<0.01 for ADP and AMP), whereas in the chronic model significant increases were noticed starting as early as 12 h after the last shock, remaining significantly elevated until the last measurement 7 days later for ATP and ADP. Analysis of hydrolysis was assessed at the selected time point of 7 days in cerebrospinal fluid samples, also demonstrating a significant activation in the chronic model (P<0.0001 for ATP and ADP). These results support the idea that adenosine nucleotides may be involved in the biochemical mechanisms underlying longer lasting therapeutic effects associated with ECT, and suggest that peripheral markers can possibly contribute to the evaluation of activity in the central nervous system.

Increased oxidative stress in the mitochondria isolated from lymphocytes of bipolar disorder patients during depressive episodes.

The present study aims to investigate the oxidative stress parameters in isolated mitochondria, as well as looking at mitochondrial complex activity in patients with Bipolar Disorder (BD) during depressive or euthymic episodes. This study evaluated the levels of mitochondrial complex (I, II, II-III and IV) activity in lymphocytes from BD patients. We evaluated the following oxidative stress parameters: superoxide, thiobarbituric acid reactive species (TBARS) and carbonyl levels in submitochondrial particles of lymphocytes from bipolar patients. 51 bipolar patients were recruited into this study: 34 in the euthymic phase, and 17 in the depressive phase. Our results indicated that the depressive phase could increase the levels of mitochondrial superoxide, carbonyl and TBARS, and superoxide dismutase, and could decrease the levels of mitochondrial complex II activity in the lymphocytes of bipolar patients. It was also observed that there was a negative correlation between the Hamilton Depression Rating Scale (HDRS) and complex II activity in the lymphocytes of depressive bipolar patients. In addition, there was a positive correlation between HDRS and superoxide, superoxide dismutase, TBARS and carbonyl. Additionally, there was a negative correlation between complex II activity and oxidative stress parameters. In conclusion, our results suggest that mitochondrial oxidative stress and mitochondrial complex II dysfunction play important roles in the depressive phase of BD.

DARPP-32 expression in rat brain after electroconvulsive stimulation.

Although electroconvulsive therapy (ECT) has been used as a treatment for mental disorder since 1930s, little progress has been made in the mechanisms underlying its therapeutic or adverse effects. The aim of this work was to analyze the expression of DARPP-32 (a protein with a central role in dopaminergic signaling) in striatum, cortex, hippocampus and cerebellum of Wistar rats subjected to acute or chronic electroconvulsive stimulation (ECS). Rats were submitted to a single stimulation (acute) or to a series of eight stimulations, applied one every 48 h (chronic). Animals were killed for collection of tissue samples at time zero, 0.5, 3, 12, 24 and 48 h after stimulation in the acute model and at the same time intervals after the last stimulation in the chronic model. Our results indicated that acute ECS produces smaller changes in the expression of DARPP-32 but, interestingly, chronic ECS increased transient expression of DARPP-32 in several time frames, in striatum and hippocampus, after the last stimulation. Results on the expression of proteins involved in signaling pathways are relevant for neuropsychiatric disorders and treatment, in particular ECT, and can contribute to shed light on the mechanisms related to therapeutic and adverse effects.

Effects of electroconvulsive seizures on Na(+),K(+)-ATPase activity in the rat hippocampus.

Although several advances have occurred concerning the use of electroconvulsive therapy, little progress has been made in understanding the mechanisms underlying its therapeutic or side effects. Na(+),K(+)-ATPase is an important enzyme of central nervous system, responsible for ionic gradient maintenance and consumption of approximately 40-50% of brain ATP. This work was performed in order to determine Na(+),K(+)-ATPase activity after acute and chronic electroconvulsive shock. Results showed an inhibition of Na(+),K(+)-ATPase activity in the hippocampus 48 h, 7, 30, 60 and 90 days after a single electroconvulsive shock. Chronic treatment diminished the enzyme activity in the hippocampus 7 and 30 days after electroconvulsive (ECS) sessions. Our findings demonstrated that Na(+),K(+)-ATPase activity is altered by ECS.

Glial fibrillary acidic protein expression after electroconvulsive shocks in rat brain.

OBJECTIVE: The aim of the present study was to assess the effect of electroconvulsive shock (ECS) in glial fibrillary acidic protein (GFAP) expression in rat brain. METHODS: Rats were given either a single (acute) or a series of eight (chronic) ECS. Brain regions were isolated and levels of glial fibrillary acidic protein (GFAP) in the brain tissue (cortex, hippocampus, and cerebellum) were assessed using an enzyme-linked immunosorbent assay (ELISA). RESULTS: We showed that GFAP expression is reduced in the hippocampus within 48 h and 7 days after acute ECS. GFAP levels are increased in the cerebellum immediately after acute and chronic ECS. No changes were observed in the cortex. CONCLUSIONS: Our findings showed a differential effect of acute and chronic ECS in the astroglial response in the brain of rats.

Acute and chronic electroconvulsive shock in rats: effects on peripheral markers of neuronal injury and glial activity.

Electroconvulsive therapy is considered one of the most effective treatments of major depression, but controversy still exists on whether it may be brain damaging. The aim of this work was to evaluate the cerebrospinal fluid (CSF) levels of neuron specific enolase (NSE), protein S100B and lactate of rats submitted to acute and chronic models of ECS. Rats were submitted to either one shock (acute) or a series of eight shocks, applied one at every 48 h (chronic). CSF samples were collected at 0, 3, 6, 12, 24, 48 and 72 h after the shock in the acute model and at these same time intervals after the last shock in the chronic model. Both models did not produce significant alterations in the levels of NSE. S100B levels were significantly increased at 6 h in the chronic model (p<0.0001). There was a significant increase in the levels of lactate at 0 h in both models (p<0.001). These results support the proposition that ECS does not produce neural damage, and suggest that the alterations in the levels of S100B and lactate may reflect an astrocytic activity of a protective nature.

No evidence for oxidative damage in the hippocampus after acute and chronic electroshock in rats.

Although several advances has occurred over the past 20 years concerning the use of electroconvulsive therapy (ECT), little progress has been made in the mechanisms underlying its therapeutic or adverse effects. Thus, this work was performed in order to determine the level of oxidative damage and antioxidant enzyme activities early and late after acute and chronic electroconvulsive shock (ECS). We demonstrated a decrease in lipid peroxidation in the hippocampus immediately after and up to 30 days after a single or multiple electroconvulsive shock. This was also true for protein carbonyls in the acute protocol. We demonstrated an increase in catalase (CAT) and superoxide dismutase (SOD) activities at different time points after single and multiple electroconvulsive shock. Our findings, for the first time, demonstrated that after electroconvulsive shock, there is an increase in antioxidant enzyme activities and we cannot demonstrate oxidative damage in the hippocampus.

[Memory consolidation and posttraumatic stress disorder]. / Consolidação da memória e estresse pós-traumático.

Extensive evidence from animal and human studies has shown that memory formation is enhanced by an endogenous modulatory system mediated by stress hormones and activation of the amygdala. This system is an evolutionarily adaptive method of enhancing important memories. Under emotional stress, this system is activated promoting the formation of vivid, long lasting traumatic memories, which are the hallmark of PTSD. The understanding of the mechanisms underlying memory modulation might lead to an improved ability to assess and treat PTSD.

Lithium and valproate modulate energy metabolism in an animal model of mania induced by methamphetamine.

Studies have shown alterations in mitochondrial complexes of bipolar disorder (BD) patients. However, changes in the Krebs cycle enzymes have been little studied. The animal model of mania induced by amphetamine has been widely used for the study of bipolar mania. The aim of this study is to assess behavioral and energy metabolism changes in an animal model of mania induced by methamphetamine (m-AMPH). Wistar rats were first given m-AMPH or saline for 14 days, and then, between days 8 and 14, rats were treated with lithium (Li), valproate (VPA), or saline (Sal). Locomotor behavior was assessed using the open-field task and activities of Krebs cycle enzymes (citrate synthase and succinate dehydrogenase), mitochondrial respiratory chain complexes (I, II, III, and IV), and creatine kinase measured in the brain structures (prefrontal, amygdala, hippocampus, and striatum). Li and VPA reversed m-AMPH-induced hyperactivity. The administration of m-AMPH inhibited the activities of Krebs cycle enzymes and complexes of the mitochondrial respiratory chain in all analyzed structures. Li and VPA reversed m-AMPH-induced energetic metabolism dysfunction; however, the effects of Li and VPA were dependent on the brain region analyzed. From the results obtained in this study, we suggested that the decreased Krebs cycle enzymes activity induced by m-AMPH may be inhibiting mitochondrial respiratory chain complexes. Therefore, changes in the Krebs cycle enzymes may also be involved in BD.

Matrix metalloproteinase-2 and metalloproteinase-9 activities are associated with blood-brain barrier dysfunction in an animal model of severe sepsis.

There is no description on the mechanisms associated with blood-brain barrier (BBB) disruption during sepsis development. Thus, we here determined changes in permeability of the BBB in an animal model of severe sepsis and the role of matrix metalloproteinase (MMP)-2 and MMP-9 in the dysfunction of the BBB. Sepsis was induced in Wistar rats by cecal ligation and perforation. BBB permeability was assessed using the Evans blue dye method. The content of MMP-2 and MMP-9 in the cerebral microvessels was determined by western blot. The activity of MMP-2 and MMP-9 was determined using zymography. An inhibitor of MMP-2 and MMP-9 or specific inhibitors of MMP-2 or MMP-9 were administered to define the role of MMPs on BBB permeability, brain inflammatory response, and sepsis-induced cognitive alterations. The increase of BBB permeability is time-related to the increase of MMP-9 and MMP-2 in the microvessels, both in cortex and hippocampus. Using an MMP-2 and MMP-9 inhibitor, or specific MMP-2 or MMP-9 inhibitors, the increase in the permeability of the BBB was reversed. This was associated with lower brain levels of interleukin (IL)-6 and lower oxidative damage. In contrast, only the inhibition of both MMP-9 and MMP-2 was able to improve acute cognitive alterations associated with sepsis. In conclusion, MMP-2 and MMP-9 activation seems to be a major step in BBB dysfunction, but BBB dysfunction seems not to be associated with acute cognitive dysfunction during sepsis development.

Behavioral changes and brain energy metabolism dysfunction in rats treated with methamphetamine or dextroamphetamine.

Studies have demonstrated that AMPHs produce long-term damage to the brain dopaminergic, serotoninergic and glutamatergic regions. Prefrontal cortex, amygdala, hippocampus and striatum appear to be involved in the toxicity and behavioral changes induced by AMPHs. A single dose of AMPH causes mitochondrial dysfunction and oxidative stress in rat brain. The goal of the present study was thus to investigate the potency of two amphetamines, dextroamphetamine (d-AMPH) and methamphetamine (m-AMPH), on the behavior and energetic dysfunction in the brain of rats. d-AMPH and m-AMPH increased the crossing and rearing behaviors. The numbers of visits to the center were increased by d-AMPH and m-AMPH only at 2mg/kg. Likewise, at a high dose (2 mg/kg), the injection of m-AMPH increased the amount of sniffing. The AMPHs significantly decreased the activities of Krebs cycle enzymes (citrate synthase and succinate dehydrogenase) and mitochondrial respiratory chain complexes (I-IV); nevertheless, this effect varied depending on the brain region evaluated. In summary, this study demonstrated that at high doses, m-AMPH, increased stereotyped (sniffing) behavior in rats, but d-AMPH did not. However, this study shows that d-AMPH and m-AMPH seem to have similar effects on the brains energetic metabolism.

Perfil clínico dos pacientes com transtorno bipolar atendidos em um ambulatório especializado na região sul catarinense / Clinical profile of patients with bipolar disorder treated at a specialized clinic in southern Santa Catarina

Introdução: O transtorno bipolar é uma doença crônica e grave, caracterizada por episódios recorrentes, representando um enorme fardo aos indivíduos acometidos e seus familiares. Objetivos: Conhecer o perfil clínico de pacientes com transtorno bipolar atendidos em um ambulatório especializado do Sul Catarinense. Metodologia: Realizou-se um estudo exploratório, descritivo, transversal, retrospectivo e de abordagem quantitativa, totalizando 50 prontuários de pacientes diagnosticados com Transtorno Bipolar tipo I conforme Entrevista Clínica Estruturada para Transtornos do Eixo I. Resultados: Da amostra, a média de idade foi de 46,6(±11,4), 68% composta por mulheres, com média de 9,1(±5,0) anos de estudos completos, 68,0% se declararam em união estável e apenas 30% exercia trabalho renumerado. A média de idade do início dos sintomas foi de 27,6(±12,2) anos, tendo a depressão como primeiro diagnóstico em 46,0% e após 9,0(±11,4) anos foi confirmado o diagnóstico. Da casuística, 16% tentaram suicídio e 52% referiram ser cicladores rápidos, a média de internações hospitalares foi de 2 internações por paciente. Conclusão: O perfil epidemiológico revelado foi composto em sua maioria por mulheres com idade superior a 40 anos, em união estável, de baixa escolaridade e sem trabalho remunerado. O início dos sintomas ocorreu mais comumente em adultos jovens, sendo a depressão o principal diagnóstico e somente após 9 anos foi que se obteve o diagnóstico correto. Afetando o curso e a gravidade, levando a maiores probabilidades de recorrência dos episódios e resultando em mais cicladores rápidos, tentativas de suicídio e internações hospitalares.

Introduction: The bipolar disorder is a chronic, serious disease characterized by recurrent episodes, representing a huge burden to the affected individuals and their familiars. Objectives: to know the clinical profile of the patients with bipolar disorder attended ina specialized ambulatory from the south of the state. Methodology: It was performed an exploratory, descriptive, cross-sectional, retrospective search of quantitative approach, having a total of 50 records of patients diagnosed with Bipolar Disorder Type I, according to the Structured Clinical Interview for Axis I Disorders. Results: From the sample, the average age was 46, 6(±11,4), 68% composed of women, with an average of 9,1 (+-5,0) years of completed studies, 68,0% of them declared themselves in a stable union and only 30% had a paid job. The average age of the beginning of the symptoms was 27, 6 (+-12, 2) years, having depression as primary diagnosis in 46, 0% of them, with the diagnosis being confirmed only after 9, 0(±11,4) years. Of casuistry, 16% attempted suicide and 52% referred being rapid cyclers, the average number of hospitalizations was 2 hospitalizations per patient. Conclusion: the revealed epidemiological profile was mainly composed by women with age over 40 years old, in a stable union, with low education and without a paid job. The initial symptoms occurred more commonly in young adults, being depression the main diagnosis. The correct diagnosis was obtained only after nine years, affecting the course and severity of the disorder, leading to higher probabilities of recurrence of the episodes and resulting in more fast cyclers, suicide attempts and hospitalizations.

Creatine kinase levels in patients with bipolar disorder: depressive, manic, and euthymic phases.

OBJECTIVE: Bipolar disorder is a severe, recurrent, and often chronic psychiatric illness associated with significant functional impairment, morbidity, and mortality. Creatine kinase is an important enzyme, particularly for cells with high and fluctuating energy requirements, such as neurons, and is a potential marker of brain injury. The aim of the present study was to compare serum creatine kinase levels between bipolar disorder patients, in the various phases (depressive, manic, and euthymic), and healthy volunteers. METHOD: Forty-eight bipolar patients were recruited: 18 in the euthymic phase; 17 in the manic phase; and 13 in the depressive phase. The control group comprised 41 healthy volunteers. The phases of bipolar disorder were defined as follows: euthymic-not meeting the DSM-IV criteria for a mood episode and scoring < 8 on the Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS); manic-scoring < 7 on the HDRS and > 7 on the YMRS; depressive-scoring > 7 on the HDRS and < 7 on the YMRS. Patients in mixed phases were excluded. Blood samples were collected from all participants. RESULTS: Creatine kinase levels were higher in the manic patients than in the controls. However, we observed no significant difference between euthymic and depressive patients in terms of the creatine kinase level. CONCLUSION: Our results suggest that the clinical differences among the depressive, manic, and euthymic phases of bipolar disorder are paralleled by contrasting levels of creatine kinase. However, further studies are needed in order to understand the state-dependent differences observed in serum creatine kinase activity.

Antibiotic therapy prevents, in part, the oxidative stress in the rat brain after meningitis induced by Streptococcus pneumoniae.

Bacterial meningitis is associated with intense inflammation and also linked to the production of reactive oxygen species. To this aim, animals underwent a magna cistern tap and received either sterile saline as a placebo or an equivalent volume of a Streptococcus pneumoniae suspension. The animals began antibiotic therapy 16h after induction. The animals were sacrificed at 24 or 48h post-infection and the hippocampus and cortex were harvested. The activity of the enzymes superoxide dismutase, catalase, and thiobarbituric acid reactive species, protein carbonyls, and free sulphydryl groups were altered, but reversed, in part, by the antibiotic treatment. Our results support the hypothesis that antibiotic treatment prevents, in part, the oxidative stress in the bacterial meningitis induced by Streptococcus pneumoniae.

Early antibiotic administration prevents cognitive impairment induced by meningitis in rats.

Neurological deficit and alterations in the hippocampus still frequently occur following bacterial meningitis in children, despite the antibiotic treatment. We investigated the long-term outcomes using early versus late antibiotic therapy in experimental pneumococcal meningitis. To this aim, male Wistar rats underwent a basilar cistern tap receiving either sterile saline as a placebo or an equivalent volume of a Streptococcus pneumoniae suspension. Antibiotics were started 8 or 16 h after infection and the animals were followed for 10 days to the determination of long-term cognitive outcomes. The animals were submitted to the habituation of an open-field as an index of long-term cognitive function. Early antibiotic administration (8 h after inoculation) when compared to late antibiotic administration (16 h after inoculation) prevented cognitive impairment induced by pneumococcal meningitis in Wistar rats. The findings from this study suggest that early antibiotic administration is an effective strategy to prevent long-term cognitive impairment in a meningitis animal model.

Brain creatine kinase activity after meningitis induced by Streptococcus pneumoniae.

Bacterial meningitis due to Streptococcus pneumoniae is associated with a significant mortality rate and persisting neurologic sequelae including sensory-motor deficits, seizures, and impairments of learning and memory. Creatine kinase (CK) is an effective buffering system of cellular ATP levels in high-energy consuming tissues; a decrease in CK activity is associated with a neurodegenerative pathway that results in neuronal loss. Thus, the aim of this study was to evaluate brain CK activity after pneumococcal meningitis. The animals underwent a magna cistern tap receiving either sterile saline as a placebo or an equivalent volume of a S. pneumoniae suspension; they were killed 6, 12, 24 and 48h after that, the brain was removed and hippocampus, striatum, cerebellum, cerebral cortex and prefrontal cortex were dissected and used for the determination of CK activity. We verified that CK activity was not altered 6 and 12h after meningitis. Interestingly, 24h after the induction of the meningitis we observed a decrease in CK activity. Finally, CK activity was not altered 48h after meningitis. Although it is difficult to extrapolate our findings to the human condition, the inhibition of brain CK activity may be involved in the pathogenesis of pneumococcal meningitis.

Tumor necrosis factor alpha (TNF-alpha) levels in the brain and cerebrospinal fluid after meningitis induced by Streptococcus pneumoniae.

Bacterial meningitis due to Streptococcus pneumoniae is associated with a significant mortality rate and persisting neurologic sequelae including sensory-motor deficits, seizures, and impairments of learning and memory. The presence of proliferating bacteria within the subarachnoid and ventricular space compartments triggers an intense inflammatory host response at killing the invading microorganism. Proinflammatory mediators released in the process include tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-1beta, IL-6. TNF-alpha have several effects, including cytotoxicity, antiviral activity, transcription factor activation, and immune response regulation. Thus, the aim of this study was to verify the levels of the TNF-alpha after pneumococcal meningitis in male Wistar rats. The animals underwent a magna cistern tap receiving either 10 microL sterile saline as a placebo or an equivalent volume of a S. pneumoniae suspension at the concentration 5 x 10(9)cfu/mL. The animals were killed at 0, 6, 12, 24, 48 and 96 h after induction. The brain was removed and hippocampus, cortex, prefrontal and cerebrospinal fluid (CSF) were isolated and used for the determination of TNF-alpha levels. We found an increase in TNF-alpha levels at 6h after induction of the meningitis in the hippocampus (p<0.01), frontal cortex (p<0.05), and cerebrospinal fluid (p<0.001).There was no alteration in the cortex. Our data suggest that TNF-alpha is involved in the pathophysiology of the pneumococcal meningitis and could be investigated as a putative biomarker for brain damage in the first hours.