Effects of lamotrigine on behavior, oxidative parameters and signaling cascades in rats exposed to the chronic mild stress model

Medicinal plants and plant-based traditional medicine: Alternative treatments for depression and their potential mechanisms of action

Background

Clinical depression is a serious public health issue that affects 4.7 % of the world's population and can lead to suicide tendencies. Although drug medications are available, only 60 % of the depressed patients respond positively to the treatments, while the rest experience side effects that resulted in the discontinuation of their medication. Thus, there is an urgent need for developing a new anti-depressant with a distinct mode of action and manageable side effects. One of the options is using medicinal plants or plant-based traditional medicine as alternative therapies for psychiatric disorders.

Objectives

Therefore, the objective of this review was twofold; to identify and critically evaluate anti-depressant properties of medicinal plants or those incorporated in traditional medicine; and to discuss their possible mechanism of action as well as challenges and way forward for this alternative treatment approach.

Methods

Relevant research articles were retrieved from various databases, including Scopus, PubMed, and Web of Science, for the period from 2018 to 2020, and the search was updated in September 2024. The inclusion criterion was relevance to antidepressants, while the exclusion criteria included duplicates, lack of full-text availability, and non-English publications.

Results

Through an extensive literature review, more than 40 medicinal plant species with antidepressant effects were identified, some of which are part of traditional medicine. The list of the said plant species included Albizia zygia (DC.) J.F.Macbr., Calculus bovis Sativus, Celastrus paniculatus Willd., Cinnamomum sp., Erythrina velutina Willd., Ficus platyphylla Delile, Garcinia mangostana Linn., Hyptis martiusii Benth, and Polygonum multiflorum Thunb. Anti-depressant mechanisms associated with those plants were further characterised based on their modes of action such as anti-oxidation system, anti-inflammation action, modulation of various neurotransmitters, neuroprotective effect, the regulation of hypothalamic-pituitary-adrenal (HPA) axis and anti-depressant mechanism. The challenges and future outlook of this alternative and complementary medicine are also explored and discussed.

Conclusion

This pool of identified plant species is hoped to offer health care professionals the best possible alternatives of anti-depressants from natural phytocompounds that are efficacious, safe and affordable for applications in future clinical settings.

Preventive impacts of vitamin C on memory damage caused by unpredictable chronic mild stress in relation to biochemical parameters in the hippocampus of male rats

The present study focused on examining the impact of vitamin C (Vit C) administration on the function of memory and the status of oxidative stress (OS) in the hippocampal area of the brain using an unpredictable chronic mild stress (UCMS) model in rats. To this end, 50 male Wistar rats (11-12 weeks of age at the start of the study) were assigned to five groups of six animals, including control, UCMS, UCMS + Vit C 50 mg/Kg, UCMS + Vit C 100 mg/Kg, and UCMS + Vit C 400 mg/Kg. The animals received daily intraperitoneal injections of Vit C at a certain time (9 am) before the initiation of a stressor. UCMS, including a progression of typical stressors, was applied for four weeks. Subsequently, using the passive avoidance (PA) and Morris water maze (MWM) tests were performed to investigate learning and memory. Eventually, hippocampal tissues were evaluated in terms of OS criteria. The results revealed that the latency to enter the dark chamber (P < 0. 01 and P < 0.05, PA test) and the time spent in the target quadrant (P < 0.0001, MWM test) were shorter in the UCMS group, while latency to discover the platform was longer (P < 0.05 and P < 0.001, MWM test) compared to the control group. However, UCMS decreased the content of thiol (P < 0.0001), as well as the activities of catalase (P < 0.0001) and superoxide dismutase (P < 0.0001), whereas the concentration of malondialdehyde (P < 0.01) increased in the hippocampal region of the brain in comparison to the control group. Interestingly, Vit C treatment reversed the mentioned effects of UCMS. Therefore, the latency to enter the dark chamber (P < 0. 05 and P < 0.01,1 and 24 h after the shock, PA test, UCMS + Vit C 400) and the time spent in the target quadrant (P < 0. 01 and P < 0.05, MWM test, UCMS + Vit C 400 and UCMS + Vit C 100, respectively) were longer in the UCMS + Vit C groups. Moreover, Vit C increased the content of thiol (P < 0.05, UCMS + Vit C 400), as well as the activity of catalase (P < 0.001, UCMS + Vit C 400) and superoxide dismutase (P < 0.0001, UCMS + Vit C 400, UCMS + Vit C 100), whereas the concentration of malondialdehyde (P < 0. 05 and P < 0.01, UCMS + Vit C 100, UCMS + Vit C 400) decreased in the hippocampal region of the brain in comparison to the UCMS group. Overall, these results suggest that Vit C could reverse UCMS-induced learning and memory impairment possibly through the modulation of brain OS.Key points Memory and learning impairments were induced by unpredictable chronic mild stress (UCMS)Vitamin C could prevent cognitive impairments caused by UCMS in rats by attenuation of oxidative stress in the brain.

Omics techniques reveal the toxicity mechanisms of three antiepileptic drugs to juvenile zebrafish (Danio rerio) brain and liver

Epilepsy, a neurological disorder, is characterized by seizures that are an appearance of excessive brain activity and is symptomatically treated with antiepileptic drugs (AEDs). Oxcarbazepine (OCBZ), lamotrigine (LTG), and carbamazepine (CBZ) are widely used AEDs in clinics and are very often detected in aquatic environments. However, neither the sub-lethal effects nor the specific mechanisms of these AEDs' action on the fish are well understood. In this study, juvenile zebrafish were exposed to a sub-lethal concentration (100 μg/L) of OCBZ, LTG, and CBZ for 28 d, after which indicators of oxidative stress (i.e. superoxide dismutase (SOD) activity, catalase (CAT) activity, and malondialdehyde (MDA) level) and neurotoxicity (i.e. acetylcholinesterase (AChE) activity, γ-aminobutyric acid (GABA) level, and glutamic acid (Glu) level) were measured. Brain SOD activity was significantly increased by three AEDs, while brain CAT activity was significantly inhibited by LTG and CBZ. Liver SOD activity was significantly enhanced by CBZ, and liver CAT activity was significantly induced by OCBZ and LTG. Liver MDA level was significantly increased by three AEDs. Brain AChE activity was significantly increased by LTG and CBZ, and brain GABA level was significantly enhanced by three AEDs. However, there were no significant alterations in the levels of MDA and Glu in zebrafish brain. To ascertain mechanisms of AEDs-induced toxicity, brain transcriptomics and liver metabolomics were conducted in zebrafish. The brain transcriptomics results showed that lots of differentially expressed genes (DEGs) were enriched in the sensory system, the immune system, the digestive system, the metabolic processes, and others in three AEDs treated groups. The metabolomics data indicated dysregulation of glycerophospholipid signaling and lipid homeostasis in zebrafish liver after three AEDs exposure. The overall results of this study improve understanding of the sub-lethal effects and potential molecular mechanisms of action of AEDs in fish.

Resveratrol exerts anxiolytic-like effects through anti-inflammatory and antioxidant activities in rats exposed to chronic social isolation

Emerging evidence has confirmed resveratrol's (RES) antioxidant, anti-inflammatory, and antidepressant effects. The beneficial effects of RES were confirmed for several emotional and cognitive deficits. This research aimed to assess the impacts of RES on behavior and hippocampal levels of anti-inflammatory and pro-inflammatory factors in rats exposed to chronic social isolation (SI) stress, which is known to induce mental disorders such as depressive-like behavior. The animals were treated by RES (20, 40, or 80 mg/kg/intraperitoneally) for 28 days following a 28-day exposure to stress. Behavioral tests, including the forced swim test (FST), open-field test (OFT), tail suspension test (TST), and sucrose preference test (SPT), assessed depressive symptoms. Finally, the animals were sacrificed, and molecular studies (qPCR and ELISA) were performed. Exposure of animals to SI dramatically increased the immobility of animals in TST and FST, enhanced the time spent in the open-field peripheral zone of the OFT, and reduced the sucrose preference rate. In addition, SI increased serum levels of corticosterone and hippocampal content of MDA, whereas it reduced hippocampal SOD and CAT activities. Moreover, SI upregulated the expression of IL-10, IL-18, and IL-1β and downregulated the expression of TGF-β in the hippocampus. RES treatment (40 & 80 mg/kg) significantly improved the behavioral alterations through the modulation of neuroinflammation and oxidative stress. The 20 mg/kg RES dose was inefficient for treating SI-induced depressive-like behavior. These results indicated that RES attenuated depressive-like behavior in prolonged stressed animals. These properties might be associated with RES-mediated improvements in serum corticosterone and hippocampal inflammatory and oxidative stress biomarkers.

Biomarkers in the Rat Hippocampus and Peripheral Blood for an Early Stage of Mental Disorders Induced by Water Immersion Stress

It is difficult to evaluate the pre-symptomatic state of mental disorders and prevent its onset. Since stress could be a trigger of mental disorders, it may be helpful to identify stress-responsive biomarkers (stress markers) for the evaluation of stress levels. We have so far performed omics analyses of the rat brain and peripheral blood after various kinds of stress and have found numerous factors that respond to stress. In this study, we investigated the effects of relatively moderate stress on these factors in the rat to identify stress marker candidates. Adult male Wistar rats underwent water immersion stress for 12 h, 24 h, or 48 h. Stress caused weight loss and elevated serum corticosterone levels, and alterations regarded as anxiety and/or fear-like behaviors. Reverse-transcription PCR and Western blot analyses revealed significant alterations in the expressions of hippocampal genes and proteins by the stress for no longer than 24 h, such as mitogen-activated protein kinase phosphatase 1 (MKP-1), CCAAT/enhancer-binding protein delta (CEBPD), small ubiquitin-like modifier proteins 1/sentrin-specific peptidase 5 (SENP5), matrix metalloproteinase-8 (MMP-8), kinase suppressor of Ras 1 (KSR1), and MKP-1, MMP-8, nerve growth factor receptor (NGFR). Similar alterations were observed in three genes (MKP-1, CEBPD, MMP-8) in the peripheral blood. The present results strongly suggest that these factors may serve as stress markers. The correlation of these factors in the blood and brain may enable the evaluation of stress-induced changes in the brain by blood analysis, which will contribute to preventing the onset of mental disorders.

An overview of the behavioral, neurobiological and morphological effects of topiramate in rats exposed to chronic unpredictable mild stress

The environmental psychological stress causes depressive disorders. Stress causes many neurobiological, neurodegenerative changes in brain. Topiramate (TPM) is used in the treatment of epilepsy and psychiatric diseases. However, there are conflicting findings that TPM disrupts cognitive functions. We aimed to investigate the effects of TPM on depression, anxiety, learning and memory as well as neurobiological, morphological changes in rats exposed to chronic unpredictable mild stress (CUMS). After CUMS was formed by random application of nine mild stressors for 45 days, TPM (at doses of 0.1, 1, 10, 100 mg/kg) was administered for 21 days. Sucrose preference, locomotor activity, forced swimming, elevated plus maze and Morris water maze tests were performed. Corticosterone, BDNF (Brain-derived neurotrophic factor) and glutamate levels and volumes of hippocampus were evaluated. Body weights of the rats were measured. Immobilization time increased in CUMS, CUMS + TPM0.1 in forced swimming test and time spent in platform quadrant increased in Control + TPM1, CUMS, CUMS + TPM0.1, CUMS + TPM1 in Morris water maze test. Control + TPM1 decreased distance to platform in Morris water maze while CUMS + TPM100 increased. Learning is impaired in CUMS + TPM100 while it is improved in Control + TPM1. BDNF levels increased in CUMS and glutamate levels increased in CUMS, CUMS + TPM10. Body weight decreased in CUMS, CUMS + TPM0.1, CUMS + TPM1, CUMS + TPM100. Hippocampus volumes increased in CUMS. In conclusion, CUMS improved cognition and this finding was supported by the increase of BDNF levels and volume of hippocampus. TPM 1 mg/kg improved cognition in non-stressed rats. TPM 0.1 and 1 mg/kg improved while TPM 100 mg/kg impaired memory in rats exposed to stress.

Hesperidin Preserves Cognitive Functions and Hippocampus Histological Architecture in Albino Wistar Rats Subjected to Stress Through Enhancement of Brain-Derived Neurotrophic Factor

Hesperidin (HSD) is a natural compound with antioxidant potential. On the other hand, chronic stress had been linked to impaired cognitive functions as it affects many neurotransmitters and brain regions such as the hippocampus. The current study was conducted to examine the effect of HSD on learning and memory after chronic mild stress. Albino Wistar rats were subjected to chronic mild stress with HSD administered as supplements. HSD was found to decrease hippocampal amyloid beta and malondialdehyde levels, in addition, to preserve cognitive functions together with preserving hippocampus histological architecture. In conclusion, the present study sheds the light on the potential of HSD to ameliorate the deleterious effects of chronic mild stress on cognitive functions through brain-derived neurotrophic factor enhancement and reduction in Aβ formation in addition to activation of the antioxidant pathway.

Vitamin D3 administration prevents memory deficit and alteration of biochemical parameters induced by unpredictable chronic mild stress in rats

The present study aimed to investigate the effects of vitamin D3 (Vit D) administration on memory function, hippocampal level of amyloid-beta (Aβ), brain-derived neurotrophic factor (BDNF) and oxidative stress status in a rat model of unpredictable chronic mild stress (UCMS). Vit D was intraperitoneally administered at doses of 100, 1000, and 10,000 IU/kg. Animals were subjected to UCMS for a total period of 4 weeks. Memory function was assessed using morris water maze (MWM) and passive avoidance (PA) tests. Biochemical markers were measured to reveal the status of oxidative stress and antioxidant defense system. In addition, the levels of Aβ and BDNF were measured in hippocampal region. In the UCMS group, latency to find the platform was greater and the time spent in target quadrant (MWM test) as well as the latency to enter the dark compartment (PA test), were less than the vehicle group. Hippocampal malondialdehyde (MDA) and Aβ concentrations in the UCMS group were higher than the vehicle group. Hippocampal level of thiol and BDNF plus the activities of catalase and superoxide dismutase (SOD) were reduced in UCMS group compared to the control subjects (i.e. vehicle group). Interestingly, Vit D treatment supplementation reversed the mentioned effects of UCMS. Our findings indicated that Vit D administration improves UCMS-induced impairment of learning and memory through prevention of adverse effects on Aβ, BDNF and oxidative stress parameters.

Molecular correlates of mitochondrial dysfunctions in major depression: Evidence from clinical and rodent studies

Major depressive disorder (MDD) is one of the most prevalent stress-related mental disorders worldwide. Several biological mechanisms underlying the pathophysiology of MDD have been proposed, including endocrine disturbances, neurotransmitter deficits, impaired neuronal plasticity, and more recently, mitochondrial dysfunctions. In this review, we provide an overview of relevant molecular correlates of mitochondrial dysfunction in MDD, based on findings from clinical studies and stress-induced rodent models. We also compare differences and similarities between the phenotypes of MDD patients and animal models. Our analysis of the literature reveals that both MDD and stress are associated, in humans and animals, with changes in mitochondrial biogenesis, redox imbalance, increased oxidative damages of cellular macromolecules, and apoptosis. Yet, a considerable amount of conflicting data exist and therefore, the translation of findings from clinical and preclinical research to novel therapies for MDD remains complex. Further studies are needed to advance our understanding of the molecular networks and biological mechanisms involving mitochondria in the pathophysiology of MDD.

Glucocorticoid Upregulates Thioredoxin-interacting Protein in Cultured Neuronal Cells

Previous studies have shown that chronic stress and chronic stress hormone treatment induce oxidative damage in rodents. Thioredoxin (Trx) is a small redox protein that plays an important role in regulation of oxidative protein cysteine modification. A Trx reduced state is maintained by thioredoxin reductase (TrxR), and the thioredoxin-interacting protein (Txnip) is an endogenous inhibitor of Trx. The purpose of this study was to investigate the effects of chronic treatment with stress hormone corticosterone on Trx, TrxR and Txnip in cultured neuronal cells. Using immunoblotting analysis we found that although chronic corticosterone treatment had no effect on Trx and TrxR protein levels, this treatment significantly increased Txnip protein levels. Using immunocytochemistry we also found that chronic corticosterone treatment increased Txnip in both nucleus and cytosol, while glucocorticoid receptor inhibitor RU486 can block corticosterone-increased Txnip protein levels. Using biotin switch, dimedone conjugation and CRISPR/Cas9 methods we found that chronic corticosterone treatment increased protein nitrosylation and sulfenylation, while knocking out Txnip blocked corticosterone-induced protein nitrosylation and sulfenylation. Since Trx can reduce cysteine oxidative protein modification such as nitrosylation and sulfenylation, our findings suggest that chronic corticosterone treatment may upregulate Txnip by targeting glucocorticoid receptor, subsequently inhibiting Trx activity and enhancing oxidative protein cysteine modification, which contributes to corticosterone-caused oxidative damage.

Differential behavioral and glial responses induced by dopaminergic mechanisms in the iNOS knockout mice

The interaction between distinctive nitric oxide synthase (NOS) isoforms and the dopamine system provides new avenues to the development of pharmacological tools for the pathophysiological conditions of the dopaminergic system. Our aim was to investigate the influences of dopamine-induced effects in inducible NOS knockout (iNOS KO) mice. In order to characterize iNOS KO mice phenotype, the animals were submitted to the basal analyses of motor, sensorimotor and sensorial abilities. Pharmacological challenging of the dopaminergic system included the investigation of amphetamine-induced prepulse inhibition (PPI) disruption, haloperidol-induced catalepsy, reserpine-induced oral involuntary movements and hyperlocomotion induced by amphetamine in reserpine treated mice. The iNOS KO mice showed significant reduction of spontaneous motor activity, but there was no significant difference in sensorimotor or sensorial responses of iNOS KO mice compared to wild type (WT). Regarding the dopaminergic system, iNOS KO mice showed a significant increase of haloperidol-induced catalepsy. This effect was confirmed through an iNOS pharmacological inhibitor (1400 W) in WT mice. In addition, iNOS KO reserpine treated mice showed reduced oral involuntary movements and amphetamine-induced hyperlocomotion. Knowing that iNOS is mainly expressed in glial cells we analyzed the immunoreactivity (ir) for GFAP (astrocyte marker) and IBA-1 (microglial marker) in the striatum, an area enrolled in motor planning among other functions. iNOS KO presented reduced GFAP-ir and IBA-1-ir compared with WT. Reserpine treatment increased GFAP-ir in both WT and iNOS KO. However, these effects were slighter in iNOS KO. Activated state of microglia was increased by reserpine only in WT mice. Our results further demonstrated that the absence of iNOS interfered with dopamine-mediated behavioral and molecular responses. These results increase the understanding of the dopamine and NO system interaction, which is useful for the management of the dopamine-related pathologies.

Molecular Mechanisms Underlying the Anti-depressant Effects of Resveratrol: a Review

Major depression is a public health problem, affecting 121 million people worldwide. Patients suffering from depression present high rates of morbidity, causing profound economic and social impacts. Furthermore, patients with depression present cognitive impairments, which could influence on treatment adherence and long-term outcomes. The pathophysiology of major depression is not completely understood yet but involves reduced levels of monoamine neurotransmitters, bioenergetics, and redox disturbances, as well as inflammation and neuronal loss. Treatment with anti-depressants provides a complete remission of symptoms in approximately 50% of patients with major depression. However, these drugs may cause side effects, as sedation and weight gain. In this context, there is increasing interest in studies focusing on the anti-depressant effects of natural compounds found in the diet. Resveratrol is a polyphenolic phytoalexin (3,4',5-trihydroxystilbene; C₁₄H₁₂O₃; MW 228.247 g/mol) and has been found in peanuts, berries, grapes, and wine and induces anti-oxidant, anti-inflammatory, and anti-apoptotic effects in several mammalian cell types. Resveratrol also elicits anti-depressant effects, as observed in experimental models using animals. Therefore, resveratrol may be viewed as a potential anti-depressant agent, as well as may serve as a model of molecule to be modified aiming to ameliorate depressive symptoms in humans. In the present review, we describe and discuss the anti-depressant effects of resveratrol focusing on the mechanism of action of this phytoalexin in different experimental models.

Mechanism of synergistic action on behavior, oxidative stress and inflammation following co-treatment with ketamine and different antidepressant classes

BACKGROUND

Major depressive disorder (MDD) affects many people in the world. However, around 40% of patients do not respond to any pharmacological drugs. An alternative is to use a combination of different pharmacological groups or the combination of a classical antidepressant with a substance that can potentiate its effect. Thus, this study aimed to investigate the synergistic interactions between different antidepressants, including fluoxetine, quetiapine and lamotrigine in combination with ketamine, a N-methyl-d-aspartate (NMDA) receptor antagonist.

METHODS

Wistar rats were acutely treated with fluoxetine (1.25mg/kg), quetiapine (5mg/kg), and lamotrigine (5.0mg/kg) alone or in combination with ketamine (5.0mg/kg), and then subjected to behavioral tests. In addition, oxidative damage and antioxidant capacity were assessed in the rat brain, and pro-inflammatory cytokines levels were evaluated in the serum.

RESULTS

It was observed a synergistic effect of ketamine in combination with fluoxetine on the immobility time in the forced swimming test, indicating an antidepressant effect. Other antidepressant did not show effects when administrated alone or joint to ketamine. The combination of ketamine with other antidepressants, particularly quetiapine, in some brain regions induced an increase in damage to lipids and proteins. However, the combination of ketamine with fluoxetine increased the antioxidant activity of superoxide dismutase, and decreased oxidative damage, thus suggesting a neuroprotective effect of the combination of these drugs. The combination of ketamine with fluoxetine or lamotrigine reduced pro-inflammatory cytokines levels.

CONCLUSION

In conclusion, ketamine induced antioxidant or pro-antioxidant effects dependent of antidepressant classes or brain area.

The effect of lamotrigine on learning in mice using the passive avoidance model

INTRODUCTION

Lamotrigine (LTG) is an antiepileptic drug that inhibits the release of glutamate by blocking sodium channels. The present study was conducted to evaluate the effect of LTG in different stages of memory using a passive avoidance learning task in mice.

METHODS

Male albino mice in the weight range 20-25g were used. They were divided into four groups (control group and three groups receiving various doses of LTG). LTG was given in three doses of 10, 25, and 50mg/kg as intraperitoneal (IP) injections. The doses of LTG were used in three injection groups: before acquisition, after consolidation, and before retrieval at 24h. The retention latency times in each group were recorded using a step-through passive avoidance task 24h and one week after consolidation.

RESULTS

Retention latency in the group receiving a high dose of LTG (25mg/kg) after one week was significantly increased in comparison to the group receiving a low dose of LTG (10mg/kg) (267±49.96 vs. 198.87±57.22, P=0.015). With injection of LTG after consolidation, the retention latency times were increased in all doses after a one-week retrieval compared to the control (P=0.023). Kaplan-Mayer surveillance analysis also showed significant differences in the latencies of the LTG-receiving group after 24h and one week's retrieval (P=0.041). Administration of LTG before retrieval at 24h showed a significant difference in retention latency time, which was increased for two doses of LTG (10 and 50mg/kg) after one week (203.5±63.67 vs. 270.25±19.78, P=0.024).

CONCLUSION

LTG at higher doses may facilitate the learning process in mice and appears to improve memory function at different stages.

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.

Tianeptine, olanzapine and fluoxetine show similar restoring effects on stress induced molecular changes in mice brain: An FT-IR study

Chronic stress which can cause a variety of disorders and illness ranging from metabolic and cardiovascular to mental leads to alterations in content, structure and dynamics of biomolecules in brain. The determination of stress-induced changes along with the effects of antidepressant treatment on these parameters might bring about more effective therapeutic strategies. In the present study, we investigated unpredictable chronic mild stress (UCMS)-induced changes in biomolecules in mouse brain and the restoring effects of tianeptine (TIA), olanzapine (OLZ) and fluoxetine (FLX) on these variations, by Fourier transform infrared (FT-IR) spectroscopy. The results revealed that chronic stress causes different membrane packing and an increase in lipid peroxidation, membrane fluidity. A significant increment for lipid/protein, C=O/lipid, CH3/lipid, CH2/lipid, PO(-)2/lipid, COO(-)/lipid and RNA/protein ratios but a significant decrease for lipid/protein ratios were also obtained. Additionally, altered protein secondary structure components were estimated, such as increment in random coils and beta structures. The administration of TIA, OLZ and FLX drugs restored these stress-induced variations except for alterations in protein structure and RNA/protein ratio. This may suggest that these drugs have similar restoring effects on the consequences of stress activity in brain, in spite of the differences in their action mechanisms. All findings might have importance in understanding molecular mechanisms underlying chronic stress and contribute to studies aimed for drug development.

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.

Oxidant/antioxidant effects of chronic exposure to predator odor in prefrontal cortex, amygdala, and hypothalamus

The incidence of anxiety-related diseases is increasing these days, hence there is a need to understand the mechanisms that underlie its nature and consequences. It is known that limbic structures, mainly the prefrontal cortex and amygdala, are involved in the processing of anxiety, and that projections from prefrontal cortex and amygdala can induce activity of the hypothalamic–pituitary–adrenal axis with consequent cardiovascular changes, increase in oxygen consumption, and ROS production. The compensatory reaction can include increased antioxidant enzymes activities, overexpression of antioxidant enzymes, and genetic shifts that could include the activation of antioxidant genes. The main objective of this study was to evaluate the oxidant/antioxidant effect that chronic anxiogenic stress exposure can have in prefrontal cortex, amygdala, and hypothalamus by exposition to predator odor. Results showed (a) sensitization of the HPA axis response, (b) an enzymatic phase 1 and 2 antioxidant response to oxidative stress in amygdala, (c) an antioxidant stability without elevation of oxidative markers in prefrontal cortex, (d) an elevation in phase 1 antioxidant response in hypothalamus. Chronic exposure to predator odor has an impact in the metabolic REDOX state in amygdala, prefrontal cortex, and hypothalamus, with oxidative stress being prevalent in amygdala as this is the principal structure responsible for the management of anxiety.

Minocycline protects against oxidative damage and alters energy metabolism parameters in the brain of rats subjected to chronic mild stress

Studies have been suggested that minocycline can be a potential new agent for the treatment of depression. In addition, both oxidative stress and energy metabolism present an important role in pathophysiology of depression. So, the present study was aimed to evaluate the effects of minocycline on stress oxidative parameters and energy metabolism in the brain of adult rats submitted to the chronic mild stress protocol (CMS). After CMS Wistar, both stressed animals as controls received twice ICV injection of minocycline (160 μg) or vehicle. The oxidative stress and energy metabolism parameters were assessed in the prefrontal cortex (PF), hippocampus (HIP), amygdala (AMY) and nucleus accumbens (Nac). Our findings showed that stress induced an increase on protein carbonyl in the PF, AMY and NAc, and mynocicline injection reversed this alteration. The TBARS was increased by stress in the PF, HIP and NAc, however, minocycline reversed the alteration in the PF and HIP. The Complex I was incrased in AMY by stress, and minocycline reversed this effect, however reduced Complex I activity in the NAc; Complex II reduced in PF and AMY by stress or minocycline; the Complex II-III increased in the HIP in stress plus minocycline treatment and in the NAc with minocycline; in the PF and HIP there were a reduced in Complex IV with stress and minocycline. The creatine kinase was reduced in AMY and NAc with stress and minocycline. In conclusion, minocycline presented neuroprotector effects by reducing oxidative damage and regulating energy metabolism in specific brain areas.

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

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

Oxidative stress as an etiological factor and a potential treatment target of psychiatric disorders. Part 2. Depression, anxiety, schizophrenia and autism

The pathophysiology of psychiatric diseases, including depression, anxiety, schizophrenia and autism, is far from being fully elucidated. In recent years, a potential role of the oxidative stress has been highlighted in the pathogenesis of neuropsychiatric disorders. A body of clinical and preclinical evidence indicates that psychiatric diseases are characterized by higher levels of oxidative biomarkers and with lower levels of antioxidant defense biomarkers in the brain and peripheral tissues. In this article, we review current knowledge on the role of the oxidative stress in psychiatric diseases, based on clinical trials and animal studies, in addition, we analyze the effects of drug-induced modulation of oxidative balance and explore pharmacotherapeutic strategies for oxidative stress reduction.

Chronic unpredictable stress impairs endogenous antioxidant defense in rat brain

Many studies have shown that chronic stress can cause neuronal damage and depression, but this exact mechanism still remains unknown. Neurons are vulnerable to lipid peroxidation-induced damage because the major part of neuronal cell membrane is polyunsaturated fatty acids that are substrate for reactive oxygen species. Since endogenous antioxidant defense systems normally eliminate production of reactive oxygen species, deficient antioxidant defense can cause oxidative stress-induced damage. In the present study, to understand the role of endogenous antioxidant defense in chronic stress-induced neuronal damage, we analyzed lipid peroxidation, total antioxidant capacity, and activities of catalase and glutathione peroxidase in frontal cortex, hippocampus and striatum of rats exposed to chronic unpredictable stress. We found that chronic unpredictable stress for four weeks in rats induced depressive-like behaviors such as anhedonia, despair and decreased exploration. Malondialdehyde, a lipid peroxidation product, is increased, but total antioxidant capacity, glutathione peroxidase activity and catalase activity are decreased in brain of rats exposed to chronic unpredictable stress. Our findings suggest that down regulation of endogenous antioxidant defense induces lipid peroxidation contributing a role to chronic stress and depression.

Lamotrigine reverses masseter overactivity caused by stress maybe via Glu suppression

Experimental and non-experimental stress significantly increase masseter muscle tone, which has been linked to the symptoms and pathogenesis of several stomatognathic system diseases. Until now, the mechanism underlying this phenomenon has remained unclear. The current study was performed to determine the mechanism of the stress-induced increase in masseter muscle tone and to investigate the effect of lamotrigine on this change. Animals challenged by repeated restraint stress received either saline as a vehicle or lamotrigine in doses of 20, 30 or 40 mg/kg body weight, whereas control animals received saline without stress treatment. Masseter muscle tone was assessed using electromyography. The activity of glutamate-related metabolic enzymes (glutaminase and glutamine synthetase) in the trigeminal motor nucleus was also investigated. Our results showed an interesting phenomenon: masseter muscle activity increased concurrently with the upregulation of the glutamate concentration after stress treatment. The activities of glutaminase and glutamine synthetase in the trigeminal motor nucleus were also upregulated and downregulated, respectively, when the rats were challenged by prolonged stress. The animals treated with lamotrigine at moderate and high doses had significantly decreased masseter muscle tone compared with stressed animals treated with vehicle. These results suggested that increased glutaminase activity and decreased glutamine synthetase activity increased glutamate production and decreased glutamate decomposition, causing an increase in glutamate levels in the trigeminal motor nucleus and eventually increasing masseter muscle tone. The administration of lamotrigine at doses of 30 or 40 mg/kg body weight effectively mitigated the adverse effects of stress on masseter muscle tone via inhibition of glutamate release.

Short-term effects of neuroactive pharmaceutical drugs on a fish species: biochemical and behavioural effects

The presence of pharmaceutical residues in the aquatic environment is receiving great attention since significant levels of contamination have been found, not only in sewage treatment plant effluents, but also in open waters. In our study, the toxicity of three anticonvulsant drugs commonly found in the environment (diazepam, carbamazepine, and phenytoin) was evaluated in Lepomis gibbosus (pumpkinseed sunfish). This study focused on oxidative stress parameters, namely: glutathione reductase (GRed), glutathione S-transferases (GSTs), catalase (CAT), and lipid peroxidation (thiobarbituric acid reactive substances, TBARS) in the hepatic, digestive, and gill tissues of exposed animals. Simultaneously, we assessed the effects of these drugs in terms of behavioural parameters, such as scototaxis and activity. Exposure to diazepam caused an increase in GST activities in the gills and an inhibition of GRed in the digestive tract, relative to control, suggesting an antioxidant response. It also caused fish to spend more time swimming and less time in a refuge area (black compartment of an aquarium). Exposure to carbamazepine caused an increase in GSTs and GRed activity in the digestive tract, which is not always consistent with the literature. A significant positive correlation was found between carbamazepine concentration and time spent in motion and a negative correlation with time spent in black compartment. Exposure to phenytoin was responsible for adaptive responses in the activities of CAT and GSTs (in the liver), but it did not elicit any behavioural alterations. Although all three drugs seemed to induce oxidative stress in some organs, peroxidative damage (measured as TBARS concentrations) was not found at the selected range of concentrations. Our results enlighten the need for more research on the ecological consequences of pharmaceuticals in the aquatic environment, especially drugs that interfere with the CNS and behaviour, because the net outcome of these effects may be difficult to predict.