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Background: Treatment of refractory bipolar disorder (BD) is extremely challenging. Deep brain stimulation (DBS) holds promise as an effective treatment intervention. However, we still understand very little about the mechanisms of DBS and its application on BD., Aim: The present study aimed to investigate the behavioural and neurochemical effects of ventral tegmental area (VTA) DBS in an animal model of mania induced by methamphetamine (m-amph)., Methods: Wistar rats were given 14 days of m-amph injections, and on the last day, animals were submitted to 20 min of VTA DBS in two different patterns: intermittent low-frequency stimulation (LFS) or continuous high-frequency stimulation (HFS). Immediately after DBS, manic-like behaviour and nucleus accumbens (NAc) phasic dopamine (DA) release were evaluated in different groups of animals through open-field tests and fast-scan cyclic voltammetry. Levels of NAc dopaminergic markers were evaluated by immunohistochemistry., Results: M-amph induced hyperlocomotion in the animals and both DBS parameters reversed this alteration. M-amph increased DA reuptake time post-sham compared to baseline levels, and both LFS and HFS were able to block this alteration. LFS was also able to reduce phasic DA release when compared to baseline. LFS was able to increase dopamine transporter (DAT) expression in the NAc., Conclusion: These results demonstrate that both VTA LFS and HFS DBS exert anti-manic effects and modulation of DA dynamics in the NAc. More specifically the increase in DA reuptake driven by increased DAT expression may serve as a potential mechanism by which VTA DBS exerts its anti-manic effects., (© 2024 The Authors. Bipolar Disorders published by John Wiley & Sons Ltd.)

Background: The etiology of bipolar disorder (BD) is multifactorial, involving both environmental and genetic factors. Current pharmacological treatment is associated with several side effects, which are the main reason patients discontinue treatment. Epigenetic alterations have been studied for their role in the pathophysiology of BD, as they bridge the gap between gene and environment., Objective: Evaluate the effects of histone deacetylase inhibitors on behavior and epigenetic enzymes activity in a rat model of mania induced by ouabain., Methods: Adult male rats were subjected to a single intracerebroventricular injection of ouabain (10 -3  M) followed by 7 days of valproate (200 mg/kg) or sodium butyrate (600 mg/kg) administration. Locomotor and exploratory activities were evaluated in the open-field test. Histone deacetylase, DNA methyltransferase, and histone acetyltransferase activity were assessed in the frontal cortex, hippocampus, and striatum., Results: Ouabain induced hyperactivity in rats, which was reversed by valproate and sodium butyrate treatment. Ouabain did not alter the activity of any of the enzymes evaluated. However, valproate and sodium butyrate decreased the activity of histone deacetylase and DNA methyltransferase. Moreover, there was a positive correlation between these two enzymes., Conclusion: These results suggest that targeting epigenetic mechanisms may play an important role in mania-like behavior management., Competing Interests: Declaration of competing interest JQ has the following declarations of interest: Clinical Research Support: Janssen Pharmaceutical (Clinical Trial), Allergan (Clinical Trial); Advisory Boards, Speaker Bureaus, Expert Witness, or Consultant: Daiichi Sankyo (Speaker Bureau); Patent, Equity, or Royalty: Instituto de Neurociencias Dr. Joao Quevedo (Stockholder); Other: Artmed Editora (Copyright), Artmed Panamericana (Copyright). All the other authors have no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Metabolic and psychiatric disorders present a bidirectional relationship. GLP-1 system, known for its insulinotropic effects, has also been associated with numerous regulatory effects in cognitive and emotional processing. GLP-1 receptors (GLP-1R) agonists present neuroprotective and antidepressant/anxiolytic properties. However, the effects of GLP-1R agonism in bipolar disorder (BD) mania and the related cognitive disturbances remains unknown. Here, we investigated the effects of the GLP-1R agonist liraglutide (LIRA) at monotherapy or combined with lithium (Li) against D-amphetamine (AMPH)-induced mania-like symptoms, brain oxidative and BDNF alterations in mice. Swiss mice received AMPH 2 mg/kg or saline for 14 days. Between days 8-14, they received LIRA 120 or 240 μg/kg, Li 47.5 mg/kg or the combination Li + LIRA, on both doses. After behavioral evaluation the brain areas prefrontal cortex (PFC), hippocampus and amygdala were collected. AMPH induced hyperlocomotion, risk-taking behavior and multiple cognitive deficits which resemble mania. LIRA reversed AMPH-induced hyperlocomotion, working and recognition memory impairments, while Li + LIRA240 rescued all behavioral changes induced by AMPH. LIRA reversed AMPH-induced hippocampal oxidative and neurotrophic changes. Li + LIRA240 augmented Li antioxidant effects and greatly reversed AMPH-induced BDNF changes in PFC and hippocampus. LIRA rescued the weight gain induced by Li in the course of mania model. Therefore, LIRA can reverse some mania-like behavioral alterations and combined with Li augmented the mood stabilizing and neuroprotective properties of Li. This study points to LIRA as a promising adjunctive tool for BD treatment and provides the first rationale for the design of clinical trials investigating its possible antimanic effect., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Evaluate the efficacy of folic acid (FA) as a therapeutic adjunct to lithium (Li) on the manic-like behaviors as well as parameters of oxidative stress and inflammation in an animal model of mania induced by m-amphetamine (m-AMPH). Wistar rats first received m-AMPH or saline (NaCl 0.9%, Sal) for 14 days. Between the 8th and 14th day, rats were treated with water, Li, FA or a combination of thereof drugs (Li + FA). Manic-like behaviors were assessed in the open-field test. Oxidative stress and inflammation parameters were assessed in the frontal cortex, striatum, and hippocampus. Administration of m-AMPH in rats significantly enhanced the exploratory and locomotor behaviors, as well as the risk-taking and stereotypic behaviors. Li + FA reversed these behavioral alterations elicited by m-AMPH. Administration of this psychostimulant also increased oxidative damage to lipids and proteins, whereas Li + FA reversed these oxidative damages. m-AMPH also induced an increase in the glutathione peroxidase (GPx) activity and a decrease in the glutathione reductase (GR) activity. Li + FA reversed the alteration in GR activity, but not in GPx activity. In addition, m-AMPH increased the IL-1β and TNF-α levels in the rat brain; Li + FA combined therapy reversed the alterations on these inflammatory parameters. FA administration per se reduced the increased TNF-α content induced by m-AMPH. Present study provides evidence that FA is effective as an adjunct to Li standard therapy on manic-like behaviors, oxidative stress and inflammatory parameters in a model of mania induced by m-AMPH.

• Imipramine induces hyperactivity in rats. • The OUA model of BD could be used as a tool to study bipolar disorder in the context of mania switch. • Alterations in the Na+ K +atpase could be involved in the manic-switch. • A drug as IMI can to trigger molecular alterations leading to mania switch. Bipolar disorder (BD) is a psychiatric disorder with complex therapy, besides the treatment with antidepressants induce a mania switch. Investigate the effect of the administration of imipramine (IMI) in rats submitted to intracerebroventricular (ICV) administrations of ouabain (OUA). Adult Wistar rats (n = 28) were submitted to only one ICV administration of OUA or artificial cerebrospinal fluid. On the 7th and 9th days following the ICV administration, animals were submitted to a behavioral analysis comprising open field task and forced swimming test. Between the 9th and 14th days, the rats received one daily intraperitoneal administration of IMI or saline (Sal). On the 15th day rats were submitted to the last session of behavioral analysis, followed by euthanasia. The frontal cortex and hippocampus were dissected for the subsequent biochemical assessments: oxidative parameters, and Na+/ K +-ATPase activity. OUA administration induced a manic-like effect on the 7th day and a depressive-like behavior on the 14th day. In contrast, IMI administration elicited significant mania switch-like effect on this same stage in animals who received OUA. OUA increased oxidative damage and activity of antioxidant enzymes in the brain of rats. IMI potentialized the oxidative damage of OUA. No significant differences between groups were observed in the Na+/ K +-ATPase activity. The present study suggests that residual effects from inhibition of the Na+ K +ATPase could be involved in the manic-switch observed in bipolar patients. Besides, the OUA model of bipolar disorder could be used to study bipolar disorder in the context of mania switch. [ABSTRACT FROM AUTHOR]

Background: There has been growing scientific evidence in recent years that bipolar disorder (BD) is associated with alterations in the kynurenine (KYN) pathway. However, many of these studies have been limited by their focus on adults. Thus, this preliminary study investigated differences in the peripheral levels of KYN metabolites in children and adolescents with BD, unaffected offspring of parents with BD, and healthy controls (HCs). Methods: Plasma samples were collected from 49 youths with BD, 19 bipolar offspring, and 31 HCs. Tryptophan (TRP), KYN, and kynurenic acid (KYNA) were separated using electrospray ionization. Results: One‐Way ANCOVA after controlling for age, gender, race, BMI‐for‐age, and smoking status showed that BD had lower levels of KYN, while unaffected high‐risk offspring subjects had lower levels of TRP, KYN, and KYNA when compared to HCs. Moreover, we found that KYN, KYN/TRP, and KYNA/KYN levels predicted the severity of depressive symptoms, while the YMRS score was not associated with any metabolite. Conclusions: In summary, this preliminary study has shown that KYN metabolites are decreased in both affected and unaffected subjects, strengthening the idea that the KYN pathway might underlie the familial risk of BD shown by high‐risk offspring individuals. However, longitudinal studies are needed to examine whether the alterations observed in this study represent early markers of risk for later developing BD. [ABSTRACT FROM AUTHOR]

Background: The present study aims to evaluate the effects of ouabain on memory and neurotrophic parameters in the brains of rats.Methods: Wistar rats received an intracerebroventricular (ICV) injection of ouabain or artificial cerebrospinal fluid (aCSF). Seven and 14 days after ICV administration, the animals were subjected to the open-field and splash tests. Furthermore, the pro-BDNF, BDNF, TrkB, and CREB were assessed in the frontal cortex and hippocampus of the rats, in both seven and 14 days after ICV injection. The memory of the animals was tested by novel object recognition test (NOR) and inhibitory avoidance task (IA), only 14 days after ICV administration.Results: Ouabain increased locomotion and exploration in the animals seven days after its administration; however, 14 days after ICV, these behavioral parameters return to the basal level. Seven days after ouabain administration increased grooming behavior in the splash test; on the other hand, seven days after ouabain injection decreased the grooming behavior, which is considered an anhedonic response. Besides, ouabain decreased recognition index in the NOR and decreased aversive memory in the IA, when compared to the control group. The levels of pro-BDNF and BDNF decreased in the frontal cortex seven days after ouabain; but its receptor (TrkB) and CREB decreased seven and 14 days after ouabain, in both cerebral structures evaluated.Conclusion: Ouabain-induced animal model of BD is an excellent model to assess memory alteration, observed in bipolar patients. Besides, the memory impairment induced by ouabain seems to be related to BDNF signaling pathway alterations. [ABSTRACT FROM AUTHOR]

Bipolar disorder (BD) is a chronic mental illness characterized by changes in mood that alternate between mania and hypomania or between depression and mixed states, often associated with functional impairment. Although effective pharmacological and non-pharmacological treatments are available, several patients with BD remain symptomatic. The advance in the understanding of the neurobiology underlying BD could help in the identification of new therapeutic targets as well as biomarkers for early detection, prognosis, and response to treatment in BD. In this review, we discuss genetic, epigenetic, molecular, physiological and neuroimaging findings associated with the neurobiology of BD. Despite the advances in the pathophysiological knowledge of BD, the diagnosis and management of the disease are still essentially clinical. Given the complexity of the brain and the close relationship between environmental exposure and brain function, initiatives that incorporate genetic, epigenetic, molecular, physiological, clinical, environmental data, and brain imaging are necessary to produce information that can be translated into prevention and better outcomes for patients with BD. [ABSTRACT FROM AUTHOR]

The present study evaluated the effects of the coadministration of lithium (Li) and Cel on inflammatory parameters in an animal model of mania induced by dextroamphetamine (D-amph). It was used Wistar rats 60 days old (250–350 g). The animals (n = 10 per group) received D-amph (2 mg/kg) or saline solution of NaCl 0.9% (Sal) intraperitoneally once a day for 14 days. From day eight until 14, the animals from the D-amph and Sal groups received Li (24 mg/kg), Cel (20 mg/kg), Li + Cel or water via gavage. Behavioral analyses were performed using the open-field test. The levels of IL-1β, IL-4, IL-10, and TNF-α were evaluated. The administration of D-amph induced hyperactivity in the rats, as well increased the IL-4, IL-10, and TNF-α levels in the serum, frontal cortex, and striatum of rats compared to those of the controls, and treatment with Li plus Cel reversed these alterations. In general, the administration of Li or Cel per se did not have effects on the behavioral and biochemical parameters. However, the treatment with Cel per se decreased only the IL-10 levels in the serum of animals. Besides, the treatment with Li or Cel decreased the IL-4 levels in the serum and reversed the effects of D-amph on this parameter in the frontal cortex. The treatment with Li reversed the effects of D-amph on the TNF-α levels in all tissues evaluated, and the administration of Cel reversed this alteration only in the striatum. It can be observed that treatment with Li plus Cel was more effective against damages caused by D-amph when compared to the administration of both treatments per se , suggesting that the coadministration can be more effective to treat BD rather than Li or Cel itself. The treatment with Li plus Cel was effective against the inflammation induced by D-amph. • D-amph induces manic-like behavior in rats. Lithium (Li) reversed the behavioral changes induced by D-amph, and D-amph increased the IL-4, IL-10, and TNFα levels. • The coadministration of Li and celecoxib reversed both alterations, behavioral, and inflammation parameters induced by D-amph. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effects of resveratrol on behavior and oxidative stress parameters in the brain of rats submitted to the animal model of mania induced by m-AMPH. In the first model (reversal treatment), rats received intraperitoneal (i.p.) injection of saline or m-AMPH (1 mg/kg body weight) once a day for 14 days, and from the 8th to the 14th day, they were orally treated with water or resveratrol (15 mg/kg), once a day. In the second model (maintenance treatment), rats were orally pretreated with water or resveratrol (15 mg/kg) once a day, and from the 8th to the 14th day, they received saline or m-AMPH i.p., once a day. Locomotor and exploratory activities were assessed in the open-field test. Oxidative and nitrosative damage parameters to lipid and proteins were evaluated by TBARS, 4-HNE, carbonyl, and 3-nitrotyrosine in the brain submitted to the experimental models. m-AMPH administration increased the locomotor and exploratory activities; resveratrol was not able to reverse or prevent these manic-like behaviors. Additionally, m-AMPH increased the lipid and protein oxidation and nitrosylation in the frontal cortex, hippocampus, and striatum of rats. However, resveratrol prevented and reversed the oxidative and nitrosative damage to proteins and lipids in all cerebral areas assessed. Since oxidative stress plays an important role in BD pathophysiology, supplementation of resveratrol in BD patients could be regarded as a possible adjunctive treatment with mood stabilizers. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effects of mood stabilizers, specifically lithium (Li) and valproate (VPA), on the PI3K/Akt signaling pathway in the brains of rats subjected to the ouabain (OUA)-induced animal model of mania. In addition, the effects of AR-A014418, a GSK-3β inhibitor, on manic-like behavior induced by OUA were evaluated. In the first experimental protocol Wistar rats received a single ICV injection of OUA or artificial cerebrospinal fluid (aCSF). From the day following ICV injection, the rats were treated for 6 days with intraperitoneal injections of saline, Li or VPA twice a day. In the second experimental protocol, rats received OUA, aCSF, OUA plus AR-A014418, or aCSF plus AR-A014418. On the 7th day after OUA injection, locomotor activity was measured using the open-field test. In addition, we analyzed the levels of p-PI3K, p -MAPK, p -Akt, and p -GSK-3β in the brain of rats by immunoblot. Li and VPA reversed OUA-related hyperactivity. OUA decreased p-PI3K, p-Akt and p-GSK-3β levels. Li and VPA improved these OUA-induced cellular dysfunctions; however, the effects of the mood stabilizers were dependent on the protein and brain region analyzed. In addition, AR-A014418 reversed the manic-like behavior induced by OUA. These findings suggest that the manic-like effects of ouabain are associated with the activation of GSK-3β, and that Li and VPA exert protective effects against OUA-induced inhibition of the GSK-3β pathway. [ABSTRACT FROM AUTHOR]

Progression of bipolar disorder (BD) has been associated with cognitive impairment and changes in neuroplasticity, including a decrease in serum brain-derived neurotrophic factor (BDNF). However, no study could examine BDNF levels directly in different brain regions after repeated mood episodes to date. The proposed animal model was designed to mimic several manic episodes and evaluate whether the performance in memory tasks and BDNF levels in hippocampus, prefrontal cortex, and amygdala would change after repeated amphetamine (AMPH) exposure. Adult male Wistar rats were divided into subchronic (AMPH for 7 days) and chronic groups (35 days), mimicking manic episodes at early and late stages of BD, respectively. After open field habituation or inhibitory avoidance test, rats were killed, brain regions were isolated, and BDNF mRNA and protein levels were measured by quantitative real-time PCR and ELISA, respectively. AMPH impaired habituation memory in both subchronic and chronic groups, and the impairment was worse in the chronic group. This was accompanied by increased Bdnf mRNA levels in the prefrontal cortex and amygdala region, as well as reduced BDNF protein in the hippocampus. In the inhibitory avoidance, AMPH significantly decreased the change from training to test when compared to saline. No difference was observed between subchronic and chronic groups, although chronically AMPH-treated rats presented increased Bdnf mRNA levels and decreased protein levels in hippocampus when compared to the subchronic group. Our results suggest that the cognitive impairment related to BD neuroprogression may be associated with BDNF alterations in hippocampus, prefrontal cortex, and amygdala. [ABSTRACT FROM AUTHOR]

Objectives Several recent studies have suggested that the physiopathology of bipolar disorder ( BD) is related to immune system alterations and inflammation. Lithium (Li) is a mood stabilizer that is considered the first-line treatment for this mood disorder. The goal of the present study was to investigate the effects of Li administration on behavior and cytokine levels [interleukin ( IL)-1β, IL-4, IL-6, IL-10, and tumor necrosis factor-alpha ( TNF-α)] in the periphery and brains of rats subjected to an animal model of mania induced by amphetamine (d- AMPH). Methods Male Wistar rats were treated with d- AMPH or saline (Sal) for 14 days; on Day 8 of treatment, the rats were administered Li or Sal for the final seven days. Cytokine ( IL-1β, IL-4, IL-6, IL-10, and TNF-α) levels were evaluated in the cerebrospinal fluid ( CSF), serum, frontal cortex, striatum, and hippocampus. Results The present study showed that d- AMPH induced hyperactivity in rats (p < 0.001), and Li treatment reversed this behavioral alteration (p < 0.001). In addition, d- AMPH increased the levels of IL-4, IL-6, IL-10, and TNF-α in the frontal cortex (p < 0.001), striatum (p < 0.001), and serum (p < 0.001), and treatment with Li reversed these cytokine alterations (p < 0.001). Conclusions Li modulates peripheral and cerebral cytokine production in an animal model of mania induced by d- AMPH, suggesting that its action on the inflammatory system may contribute to its therapeutic efficacy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effects of mood stabilizers, specifically lithium (Li) and valproate (VPA), on mitochondrial superoxide, lipid peroxidation, and proteins involved in cell death signaling pathways in the brains of rats subjected to the ouabain-induced animal model of mania. Wistar rats received Li, VPA, or saline twice a day for 13 days. On the 7th day of treatment, the animals received a single intracerebroventricular injection of ouabain or aCSF. After the ICV injection, the treatment with mood stabilizers continued for 6 additional days. The locomotor activity of rats was measured using the open-field test. In addition, we analyzed oxidative stress parameters, specifically levels of phosphorylated p53 (pp53), BAX and Bcl-2 in the brain of rats by immunoblot. Li and VPA reversed ouabain-related hyperactivity. Ouabain decreased Bcl-2 levels and increased the oxidative stress parameters BAX and pp53 in the brains of rats. Li and VPA improved these ouabain-induced cellular dysfunctions; however, the effects of the mood stabilizers were dependent on the protein and brain region analyzed. These findings suggest that the Na + /K + -ATPase can be an important link between oxidative damage and the consequent reduction of neuronal and glial density, which are both observed in BD, and that Li and VPA exert protective effects against ouabain-induced activation of the apoptosis pathway. [ABSTRACT FROM AUTHOR]

Bipolar disorder (BD) is a chronic and severe psychiatric disorder and despite its importance, little is known about the precise pathophysiology of this disorder. Several studies have reported that inflammation plays a role in the pathogenesis of BD and that cytokines are altered in these patients. Intracerebroventricular (ICV) injection of ouabain (a potent Na + /K + -ATPase inhibitor) in rats resulted in manic-like effects and it has been widely used as an animal model of bipolar mania. In this study, we assessed the cytokine levels (IL-1β, IL-6, IL-10, TNF-α, CINC-1) in the brain structures (hippocampus, striatum, frontal cortex, amygdala), serum and cerebrospinal fluid (CSF) of rats submitted to an animal model of mania induced by ouabain. Our findings demonstrated that ouabain induced hyperlocomotion in rats. However, the only cytokine that showed alteration was IL-6, which was decreased in the striatum after ouabain administration. In conclusion, despite the ouabain administration in rats be a valid model to study the physiopathology of bipolar mania, it seems that this model was not able to mimic the changes in cytokines observed in bipolar patients. [ABSTRACT FROM AUTHOR]

Abstract: The neurobiological basis of bipolar disorder (BD) remains unknown; nevertheless, mitochondrial dysfunction has been identified in this disorder. Inactivation of any step in the tricarboxylic acid (TCA) cycle can impair mitochondrial ATP production. There is recent evidence indicating that PKC is an important therapeutic target for bipolar disorder. Therefore, we evaluated the effects of tamoxifen (TMX—a PKC inhibitor) on the activities of enzymes in the TCA cycle of rat brains subjected to an animal model of mania induced by amphetamine. In the reversal treatment, Wistar rats were first treated with d-AMPH or saliratsne (Sal) for 14 days. Thereafter, between days 8 and 14, the rats were administered TMX or Sal. The citrate synthase, succinate dehydrogenase, and malate dehydrogenase were evaluated in the frontal cortex, hippocampus, and striatum. The d-AMPH administration inhibited TCA cycle enzymes activity in all analyzed structures, and TMX reversed d-AMPH-induced dysfunction. In addition, we observed a negative correlation between d-AMPH-induced hyperactivity and the activity of these enzymes in the rat's brain. These findings suggested that TCA cycle enzymes inhibition can be an important link for the mitochondrial dysfunction seen in BD, and TMX exert protective effects against the d-AMPH-induced TCA cycle enzymes dysfunction. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Several evidences have demonstrated that oxidative stress has a central role in bipolar disorder (BD). Recently, studies have been suggested histone deacetylases (HDAC) as a possible target for new medications in treatment of mood disorders. In this study, we investigated the effects of sodium butyrate (SB, a histone deacetilase inhibitor) on oxidative stress in rats submitted to an animal model of mania induced by d-amphetamine (d-AMPH). Wistar rats were first given d-AMPH or saline (Sal) for 14days, and then, between days 8 and 14, rats were treated with SB or Sal. Locomotor activity and risk-taking behavior were assessed by open-field test and oxidative stress was measured in prefrontal cortex, amygdala, hippocampus and striatum. The results showed that SB reversed and prevented d-AMPH-induced behavioral effects. The d-AMPH administration induced oxidative damage in all brain structures analyzed. Depending on the cerebral area and technique, SB was able to reverse this impairment. The present study reinforces the need for more studies of HDAC inhibitors as possible target for new medications in treatment for BD. [Copyright &y& Elsevier]

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. [ABSTRACT FROM PUBLISHER]

Freitas TP, Rezin GT, Fraga DB, Moretti M, Vieira JS, Gomes LM, Borges LS, Valvassori SS, Quevedo J, Streck EL. Mitochondrial respiratory chain activity in an animal model of mania induced by ouabain. Bipolar disorder (BD) is a mental illness associated with higher rates of suicide. The present study aims to investigate the brain mitochondrial respiratory chain activity in an animal model of mania induced by ouabain. Adult male Wistar rats received a single intracerebroventricular administration of ouabain (10 and 10 M) or vehicle. Locomotor activity was measured using the open field test. Mitochondrial respiratory chain activity was measured in the brain of rats 1 h and 7 days after ouabain administration. Our results showed that spontaneous locomotion was increased 1 h and 7 days after ouabain administration. Complexes I, III and IV activities were increased in the prefrontal cortex, hippocampus and striatum immediately after the administration of ouabain, at the concentration of 10 and 10 M. Moreover, complex II activity was increased only in the prefrontal cortex at the concentration of 10 M. On the other hand, no significant alterations were observed in complex I activity 7 days after ouabain administration. However, an increase in complexes II, III and IV activities was observed only in the prefrontal cortex at the concentration of 10 M. Our findings suggest an increase in the activities of mitochondrial respiratory chain in this model of mania. A possible explanation is that these findings occur as a rebound effect trying to compensate for a decrease of ATP deprivation in BD. The present findings suggest that this model may present good face validity and a limitation in construct validity. [ABSTRACT FROM AUTHOR]

Abstract: The present study aimed to investigate the effects of tamoxifen (TMX) on locomotor behavior and on the activities of mitochondrial respiratory chain complexes and creatine kinase (CK) in the brain of rats subjected to an animal model of mania induced by d-amphetamine (d-AMPH)—reversion and prevention protocols. The d-AMPH administration increased locomotor activity in saline-treated rats under prevention and reversion treatment; furthermore, there was evident reduction in the locomotion in the d-amphetamine group treated with TMX. d-AMPH significantly decreased the activity of mitochondrial respiratory chain complexes in saline-treated rats in prefrontal cortex, hippocampus, striatum and amygdala in both prevention and reversion treatment. Depending on the cerebral area and evaluated complex, TMX was able to prevent and reverse this impairment. A decrease in CK activity was also verified in the brain of rats when d-AMPH was administrated in both experiments; the administration of TMX reversed but not prevented the decrease in CK activity induced by d-AMPH. The present study demonstrated that TMX reversed and prevented the alterations in behavioral and energy metabolism induced by d-AMPH (alterations were also observed in bipolar disorder), reinforcing the need for more studies about inhibitors of PKC as possible targets for new medications in the treatment of bipolar disorder. [Copyright &y& Elsevier]

Abstract: In this study, we assessed the oxidative stress parameters in rats submitted to an animal model of mania induced by ouabain (OUA), which included the use of lithium (Li) and valproate (VPA). Li and VPA treatment reversed and prevented the OUA-induced damage in these structures, however, this effect varies depending on the brain region and treatment regimen. Moreover, the activity of the antioxidant enzymes, namely, superoxide dismutase (SOD) and catalase (CAT) was found to be increased and decreased, respectively, in the brain of OUA-administered rats. Li and VPA modulated SOD and CAT activities in OUA-subjected rats in both experimental models. Our results support the notion that Li and VPA exert antioxidant-like properties in the brain of rats submitted to animal model of mania induced by ouabain. [ABSTRACT FROM AUTHOR]

Cannabidiol (CBD), a Cannabis sativa constituent, may present a pharmacological profile similar to mood stabilizing drugs, in addition to anti-oxidative and neuroprotective properties. The present study aims to directly investigate the effects of CBD in an animal model of mania induced by D-amphetamine (D-AMPH). In the first model (reversal treatment), rats received saline or D-AMPH (2 mg/kg) once daily intraperitoneal (i.p.) for 14 days, and from the 8th to the 14th day, they were treated with saline or CBD (15, 30 or 60 mg/kg) i.p. twice a day. In the second model (prevention treatment), rats were pretreated with saline or CBD (15, 30, or 60 mg/kg) regime i.p. twice a day, and from the 8th to the 14th day, they also received saline or D-AMPH i.p. once daily. In the hippocampus CBD (15 mg/kg) reversed the D-AMPH-induced damage and increased (30 mg/kg) brain-derived neurotrophic factor (BDNF) expression. In the second experiment, CBD (30 or 60 mg/kg) prevented the D-AMPH-induced formation of carbonyl group in the prefrontal cortex. In the hippocampus and striatum the D-AMPH-induced damage was prevented by CBD (15, 30 or 60 mg/kg). At both treatments CBD did not present any effect against D-AMPH-induced hyperactivity. In conclusion, we could not observe effects on locomotion, but CBD protect against D-AMPH-induced oxidative protein damage and increased BDNF levels in the reversal model and these effects vary depending on the brain regions evaluated and doses of CBD administered. [ABSTRACT FROM PUBLISHER]

Abstract: Bipolar disorder (BD) is a devastating major mental illness associated with high rates of suicide and work loss. There is an emerging body of data suggesting that bipolar disorder is associated with mitochondrial dysfunction. In this context, the present study aims to investigate the effects of mood stabilizers lithium (Li) and valproate (VPT) on mitochondrial respiratory chain activity in brain of rats undergoing treatment with the pro-manic agent d-AMPH d-amphetamine (d-AMPH). In the reversal treatment, Wistar rats were first given d-AMPH or saline for 14 days, and then, between days 8 and 14, rats were treated with Li, VPA or saline (Sal). In the prevention treatment, rats were pretreated with Li, VPA or Sal. Locomotor behavior was assessed using the open-field task and mitochondrial chain activity complexes I, II, III and IV were measured in brain structures (hippocampus, striatum and prefrontal). Li and VPA reversed and prevented d-AMPH-induced hyperactivity. In both experiments, d-AMPH inhibited mitochondrial respiratory chain activity in all analyzed structures. In the reversal treatment, VPA reversed d-AMPH-induced dysfunction in all brain regions analyzed. In the prevention experiment, the effects of Li and VPA on d-AMPH-induced mitochondrial dysfunction were dependent on the brain region analyzed. These findings suggested that dopamine can be an important link for the mitochondrial dysfunction seen in BD and, Li and VPA exert protective effects against this d-AMPH-induced mitochondrial dysfunction, but this effect varies depending on the brain region and the treatment regimen. [ABSTRACT FROM AUTHOR]

Abstract: Intracerebroventricular (ICV) injection of ouabain (a potent Na+/K+-ATPase inhibitor) in rats resulted in manic-like effects. There is an emerging body of data indicating that major neuropsychiatric disorders, such as bipolar disorder and schizophrenia, are associated with increased oxidative stress. In this study, we investigated the effects of ICV ouabain injection on oxidative stress parameters in total tissue of rat brain. Our findings demonstrated that ICV injection increased thiobarbituric acid reactive species levels and protein carbonyl generation in the prefrontal cortex and hippocampus of rats. Moreover, the activity of the antioxidants enzymes catalase and superoxide dismutase was altered in several areas of the rat brain and cerebrospinal fluid of ICV ouabain-subjected rats. These results showed that Na+/K+-ATPase inhibition can lead to oxidative stress in the brain of rats. [Copyright &y& Elsevier]

Abstract: The intracerebroventricular (ICV) administration of ouabain (a Na+/K+-ATPase inhibitor) in rats has been suggested to mimic some symptoms of human bipolar mania. Clinical studies have shown that bipolar disorder may be related to mitochondrial dysfunction. Herein, we investigated the behavioral and biochemical effects induced by the ICV administration of ouabain in rats. To achieve this aim, the effects of ouabain injection immediately after and 7 days following a single ICV administration (at concentrations of 10−2 and 10−3 M) on locomotion was measured using the open-field test. Additionally, thiobarbituric acid reactive substances (TBARSs) and superoxide production were measured in submitochondrial particles of the prefrontal cortex, hippocampus, striatum and amygdala. Our findings demonstrated that ouabain at 10−2 and 10−3 M induced hyperlocomotion in rats, and this response remained up to 7 days following a single ICV injection. In addition, we observed that the persistent increase in the rat spontaneous locomotion is associated with increased TBARS levels and superoxide generation in submitochondrial particles in the prefrontal cortex, striatum and amygdala. In conclusion, ouabain-induced mania-like behavior may provide a useful animal model to test the hypothesis of the involvement of oxidative stress in bipolar disorder. [Copyright &y& Elsevier]

We evaluated Na+,K+-ATPase activity in hippocampus of rats submitted to an animal model of mania which included the use of lithium and valproate. In the acute treatment, amphetamine or saline was administered to rats for 14 days, between day 8 and 14, rats were treated with lithium, valproate or saline. In the maintenance treatment, rats were treated with lithium, valproate or saline, between day 8 and 14, amphetamine or saline were administered. Locomotor activity was assessed by open field test and Na+,K+-ATPase activity was measured. Our results showed that mood stabilizers reversed and prevented amphetamine-induced behavioral effects. Moreover, amphetamine (acute treatment) increased Na+,K+-ATPase activity, and administration of lithium or valproate reversed this effect. In the maintenance treatment, amphetamine increased Na+,K+-ATPase activity in saline-pretreated rats. Amphetamine administration in lithium- or valproate-pretreated animals did not alter Na+,K+-ATPase activity. The findings suggest that amphetamine-induced hyperactivity may be associated with an increase in Na+,K+-ATPase. [ABSTRACT FROM AUTHOR]

The authors reflect on the psychiatric illness called bipolar disorder (BD), which is usually characterized by recurrent episodes of mania and depression related with a high rate of medical and psychiatric comorbidities. They cite the current authorized treatments for BD such as lithium, valproate and antipsychotics. They focus on the biological mechanisms that underlie the neuroprogression in BD.

Bipolar disorder (BD) is a complex and severe mental disorder that affects 1–3 % of the world population. Studies have suggested the involvement of oxidative stress in the physiopathology of this psychiatry disorder. Folic acid (FA), a vitamin from the B complex, is a nutraceutical that has recently been researched as a possible treatment for BD since folate is reduced in patients with the disorder. The present study aimed to evaluate the effects of lithium (Li) and FA on behavioral changes and oxidative stress parameters in an animal model of mania induced by ouabain (OUA). Wistar rats received a single intracerebroventricular (ICV) injection of OUA or artificial cerebrospinal fluid (aCSF). From the day following ICV injection, the rats were treated for seven days with gavage injections of Li (47.5 mg/kg/mL), FA (50 mg/kg/mL), or water (1 mL/kg). On the 7th day after OUA injection, locomotor activity was measured using the open-field test. In addition, the oxidative stress parameters were evaluated in rats' frontal cortex, striatum, and hippocampus. OUA induced mania-like behavior and oxidative stress in rats' brains, but Li could reverse these alterations. FA did not affect behavior parameters; however, it presents an antioxidant effect on the brain structures evaluated. The study was only evaluated male rats and ICV injection is an invasive procedure. These results indicate that even though FA has an effect against the oxidative stress induced by OUA, this effect was not strong enough to interfere with behavior parameters. • Ouabain induces hyperactivity and oxidative stress in Wistar rats. • Lithium reverted hyperactivity and oxidative stress induced by ouabain. • Folic acid did not revert hyperactivity induced by ouabain. • Folic acid protected the brain against oxidative damage induced by ouabain. [ABSTRACT FROM AUTHOR]

Abstract: 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 6days 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 12days. 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 6days. 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. [Copyright &y& Elsevier]

Abstract Studies have suggested the involvement of oxidative stress in the physiopathology of bipolar disorder. Preclinical data have shown that PKC inhibitors may act as mood-stabilizing agents and protect the brain in animal models of mania. The present study aimed to evaluate the effects of Lithium (Li) or tamoxifen (TMX) on behavioral changes and oxidative stress parameters in an animal model of mania induced by ouabain (OUA). Wistar rats received a single intracerebroventricular (ICV) injection of OUA or artificial cerebrospinal fluid (ACSF). From the day following ICV injection, the rats were treated for seven days with intraperitoneal injections of saline, Li or TMX twice a day. On the 7th day after OUA injection, locomotor activity was measured using the open-field test, and the oxidative stress parameters were evaluated in the hippocampus and frontal cortex of rats. The results showed that OUA induced hyperactivity in rats, which is considered a manic-like behavior. Also, OUA increased lipid peroxidation and oxidative damage to proteins, as well as causing alterations to antioxidant enzymes in the frontal cortex and hippocampus of rats. The Li or TMX treatment reversed the manic-like behavior induced by OUA. Besides, Li, but not TMX, reversed the oxidative damage caused by OUA. These results suggest that the manic-like effects induced by OUA and the antimanic effects of TMX seem not to be related to the oxidative stress. [ABSTRACT FROM AUTHOR]

The current pathophysiological understanding of mechanisms leading to onset and progression of bipolar manic episodes remains limited. At the same time, available animal models for mania have limited face, construct, and predictive validities. Additionally, these models fail to encompass recent pathophysiological frameworks of bipolar disorder (BD), e.g. neuroprogression. Therefore, there is a need to search for novel preclinical models for mania that could comprehensively address these limitations. Herein we review the history, validity, and caveats of currently available animal models for mania. We also review new genetic models for mania, namely knockout mice for genes involved in neurotransmission, synapse formation, and intracellular signaling pathways. Furthermore, we review recent trends in preclinical models for mania that may aid in the comprehension of mechanisms underlying the neuroprogressive and recurring nature of BD. In conclusion, the validity of animal models for mania remains limited. Nevertheless, novel (e.g. genetic) animal models as well as adaptation of existing paradigms hold promise. [ABSTRACT FROM AUTHOR]

Abstract: Bipolar disorder (BD) is a chronic, prevalent, and highly debilitating psychiatric illness characterized by recurrent manic and depressive episodes. Mood stabilizing agents such as lithium and valproate are two primary drugs used to treat BD. To develop a novel animal model of mania (hallmark of BD), it is important to assess the therapeutic and prophylactic effect of these mood stabilizers on the new candidate target animal model. The present work investigates the therapeutic and prophylactic value of lithium and valproate in a novel preclinical animal model of mania, induced by ketamine. In the prevention protocol, wistar rats were pretreated with lithium (47.5 mg/kg, i.p., twice a day), valproate (200 mg/kg, i.p., twice a day), or saline (i.p., twice a day) for 14 days. Between days 8 and 14, the rats were treated with ketamine (25 mg/kg, i.p.) or saline. In the reversal protocol, rats first received ketamine (25 mg/kg, i.p.) or saline. After, the administration of lithium, valproate, or saline was carried out for seven days. Our results indicated that lithium and valproate reversed and prevented ketamine-induced hyperlocomotion. Moreover, lithium and valproate reversed (prefrontal cortex, hippocampus, and striatum) and prevented (prefrontal cortex, hippocampus, striatum, and amygdala) the increase of the TBARS level induced by ketamine. The protein carbonyl formation, induced by ketamine, was reversed by lithium and valproate in the prefrontal cortex, hippocampus, and striatum, and prevented only in the amygdala. These findings support the notion that the administration of ketamine might be a promising pharmacological animal model of mania, which could play a role in the pathophysiology of BD. [Copyright &y& Elsevier]

Abstract: It has been demonstrated that lithium (Li) and valproate (VPT), first line mood stabilizers, increase BDNF content in rat hippocampus and frontal cortex, which suggests that the regulation of neurotrophic factors might be associated with their pharmacological effects. In sight of the scarcity of studies with other neurotrophins, and the possible relevance of multiple neurotrophic signaling systems in bipolar disorder we investigated the effects of Li and VPT on NT-3 levels in rat serum and hippocampus, using an animal model of mania induced by amphetamine (AMPH). In the reversal model, adult male Wistar rats received AMPH or saline for 14 days, and between the 8th and 14th days, animals were treated with Li, VPT or saline. In the prevention model, rats were pretreated with Li, VPT or saline, and between the 8th and 14th days, the animals received AMPH or saline. Li increased serum and hippocampal NT-3 levels in all conditions, whereas VPT increased hippocampal NT-3 in the prevention model only. Li reversed AMPH changes in NT-3 in the reversal model, and VPT prevented AMPH changes in NT-3 in the prevention model. These results suggest that both Li and VPT modulate serum and central (hippocampal) NT-3 levels, and further support that the regulation of neurotrophic signaling systems may be related to the mechanisms of action of mood stabilizers. [Copyright &y& Elsevier]

Abstract: There is evidence pointing to dysfunction at the mitochondrial level as an important target for the understanding of the pathophysiology of bipolar disorder (BD). We assessed creatine kinase (CK) activity in rats submitted to an animal model of mania which included the use of lithium and valproate. In the acute treatment, amphetamine (AMPH) or saline was administered to rats for 14 days, and between day 8 and 14, rats were treated with either lithium, valproate or saline. In the maintenance treatment, rats were pretreated with lithium, valproate or saline, and between day 8 and 14, AMPH or saline were administered. In both experiments, locomotor activity was assessed by open-field test and CK activity was evaluated in hippocampus, striatum, cerebellum, whole cortex and prefrontal cortex. Our results showed that mood stabilizers reversed AMPH-induced behavioral effects. Moreover, AMPH (acute treatment) inhibited CK activity in hippocampus, striatum and cortex, but not in cerebellum and prefrontal cortex, and administration of lithium or valproate did not reverse the enzyme inhibition. In the maintenance treatment, AMPH decreased CK activity in saline-pretreated rats in hippocampus, striatum and cortex, but not in cerebellum and prefrontal cortex. AMPH administration in lithium- or valproate-pretreated animals decreased CK activity in hippocampus, striatum and cortex. Our results showed that AMPH inhibited CK activity and that mood stabilizers were not able to reverse and/or prevent the enzyme inhibition. These findings reinforce the hypothesis that mitochondrial dysfunction plays an important role in the pathophysiology of BD. [Copyright &y& Elsevier]

Abstract: There is an emerging body of data suggesting that mood disorders are associated with decreased brain-derived neurotrophic factor (BDNF). The present study aims to investigate the effects of the mood stabilizers lithium (Li) and valproate (VPT) in an animal model of bipolar disorder. In the first experiment (acute treatment), rats were administered d-amphetamine (AMPH) or saline for 14 days, and then between day 8 and 14, rats were treated with either Li, VPT or saline. In the second experiment (maintenance treatment), rats were pretreated with Li, VPT or saline, and then between day 8 and 14, rats were administered AMPH or saline. In both experiments, locomotor activity was measured using the open-field test and BDNF levels were measured in rat hippocampus by sandwich-ELISA. Li and VPT reversed AMPH-induced behavioral effects in the open-field test in both experiments. In the first experiment, Li increased BDNF levels in rat hippocampus. In the second experiment, AMPH decreased BDNF levels and Li and VPT increased BDNF levels in rat hippocampus. Our results suggest that the present model fulfills adequate face, construct and predictive validity as an animal model of mania. [Copyright &y& Elsevier]