Antidepressant-like activity of magnesium in the olfactory bulbectomy model is associated with the AMPA/BDNF pathway

Neurological manifestations of hypermagnesemia: a narrative review

Hypermagnesemia is a rare but potentially fatal electrolyte disorder. High serum magnesium levels have been associated with the development of neurological manifestations such as dysautonomia, muscle weakness, respiratory failure, and altered level of consciousness from drowsiness to coma. Although rare, some subjects, such as those with chronic renal failure and those taking magnesium supplements or medications, are at risk of developing this condition. Recognizing this electrolyte alteration promptly allows for an immediate initiation of a therapeutic strategy that is often resolutive when addressed in time. This paper aims to review the neurological complications associated with hypermagnesemia, their pathophysiology, and management.

Magnesium for disease treatment and prevention: emerging mechanisms and opportunities

Magnesium (Mg2+) is a commonly used dietary supplement for the prevention and treatment of diseases. However, the efficacy and mechanisms of action of Mg2+ in most diseases have been controversial because of conflicting findings in earlier studies. Recent clinical and preclinical studies provide novel insights into the use of Mg2+ for the treatment and prevention of diseases affecting different organ systems. In this review, we provide an overview of recent clinical evidence for, and controversies over, the medical benefits of Mg2+. In addition, we critically discuss recent advances in understanding the mechanisms of action of Mg2+, which could enable the development of novel targeted therapies.

Repeated Sulforaphane Treatment Reverses Depressive-like Behavior and Exerts Antioxidant Effects in the Olfactory Bulbectomy Model in Mice

Growing evidence suggests that activators of nuclear factor erythroid-derived 2-like 2 (Nrf2), such as sulforaphane, may represent promising novel pharmacological targets for conditions related to oxidative stress, including depressive disorder. Therefore, we conducted a study to explore the behavioral and biochemical effects of repeated (14 days) sulforaphane (SFN) treatment in the olfactory bulbectomy (OB) animal model of depression. An open field test (OFT), splash test (ST), and spontaneous locomotor activity test (LA) were used to assess changes in depressive-like behavior and the potential antidepressant-like activity of SFN. The OB model induced hyperactivity in mice during the OFT and LA as well as a temporary loss of self-care and motivation in the ST. The repeated administration of SFN (10 mg/kg) effectively reversed these behavioral changes in OB mice across all tests. Additionally, a biochemical analysis revealed that SFN (10 mg/kg) increased the total antioxidant capacity in the frontal cortex and serum of the OB model. Furthermore, SFN (10 mg/kg) significantly enhanced superoxide dismutase activity in the serum of OB mice. Overall, the present study is the first to demonstrate the antidepressant-like effects of repeated SFN (10 mg/kg) treatment in the OB model and indicates that these benefits may be linked to improved oxidative status.

Magnesium (Mg2+): Essential Mineral for Neuronal Health: From Cellular Biochemistry to Cognitive Health and Behavior Regulation

Magnesium (Mg2+) is a crucial mineral involved in numerous cellular processes critical for neuronal health and function. This review explores the multifaceted roles of Mg2+, from its biochemical interactions at the cellular level to its impact on cognitive health and behavioral regulation. Mg2+ acts as a cofactor for over 300 enzymatic reactions, including those involved in ATP synthesis, nucleic acid stability, and neurotransmitter release. It regulates ion channels, modulates synaptic plasticity, and maintains the structural integrity of cell membranes, which are essential for proper neuronal signaling and synaptic transmission. Recent studies have highlighted the significance of Mg2+ in neuroprotection, showing its ability to attenuate oxidative stress, reduce inflammation, and mitigate excitotoxicity, thereby safeguarding neuronal health. Furthermore, Mg2+ deficiency has been linked to a range of neuropsychiatric disorders, including depression, anxiety, and cognitive decline. Supplementation with Mg2+, particularly in the form of bioavailable compounds such as Magnesium-L-Threonate (MgLT), Magnesium-Acetyl-Taurate (MgAT), and other Magnesium salts, has shown some promising results in enhancing synaptic density, improving memory function, and alleviating symptoms of mental health disorders. This review highlights significant current findings on the cellular mechanisms by which Mg2+ exerts its neuroprotective effects and evaluates clinical and preclinical evidence supporting its therapeutic potential. By elucidating the comprehensive role of Mg2+ in neuronal health, this review aims to underscore the importance of maintaining optimal Mg2+ levels for cognitive function and behavioral regulation, advocating for further research into Mg2+ supplementation as a viable intervention for neuropsychiatric and neurodegenerative conditions.

Neuroprotective effects of magnesium against stress induced by hydrogen peroxide in Wistar rat

INTRODUCTION

Oxidative stress has been implicated in the pathogenesis of diverse disease states. The present study was designed to examine the effects of magnesium sulphate (MgSO4) against hydrogen peroxide (H2O2) induced behaviour impairment and oxidative damage in rats.

MATERIAL AND METHODS

Eighteen rats were equally divided into three groups. The first group was kept as a control. In the second group, H2O2 was given in drinking water at 3% during 5 days. In the third group, rats were subjected to daily administration of H2O2 and MgSO4 (100 mg/kg; b.w) for 5 days. Animals were subjected to behavioural tests (elevated plus maze and open field). At the end of experiment, brains were extracted for oxidative stress biomarkers assessment including levels of malondialdéhyde and hydrogen peroxide and activities of superoxide dismutase and catalase.

RESULTS

Our findings showed that H2O2 treated rat exhibited anxiogenic behaviour and the genesis of free radicals in the brain. Magnesium showed amelioration against oxidative stress and significant decrease in anxiety levels.

DISCUSSION AND CONCLUSION

Stress is a powerful process that disrupts brain homeostasis by inducing oxidative stress and its appear that magnesium may have potential therapeutic benefits by reducing oxidative stress and inducing anxiolytic effect.

Magnesium and the Brain: A Focus on Neuroinflammation and Neurodegeneration

Magnesium (Mg) is involved in the regulation of metabolism and in the maintenance of the homeostasis of all the tissues, including the brain, where it harmonizes nerve signal transmission and preserves the integrity of the blood-brain barrier. Mg deficiency contributes to systemic low-grade inflammation, the common denominator of most diseases. In particular, neuroinflammation is the hallmark of neurodegenerative disorders. Starting from a rapid overview on the role of magnesium in the brain, this narrative review provides evidences linking the derangement of magnesium balance with multiple sclerosis, Alzheimer's, and Parkinson's diseases.

Postsynaptic Proteins at Excitatory Synapses in the Brain—Relationship with Depressive Disorders

Depressive disorders (DDs) are an increasingly common health problem that affects all age groups. DDs pathogenesis is multifactorial. However, it was proven that stress is one of the most important environmental factors contributing to the development of these conditions. In recent years, there has been growing interest in the role of the glutamatergic system in the context of pharmacotherapy of DDs. Thus, it has become increasingly important to explore the functioning of excitatory synapses in pathogenesis and pharmacological treatment of psychiatric disorders (including DDs). This knowledge may lead to the description of new mechanisms of depression and indicate new potential targets for the pharmacotherapy of illness. An excitatory synapse is a highly complex and very dynamic structure, containing a vast number of proteins. This review aimed to discuss in detail the role of the key postsynaptic proteins (e.g., NMDAR, AMPAR, mGluR5, PSD-95, Homer, NOS etc.) in the excitatory synapse and to systematize the knowledge about changes that occur in the clinical course of depression and after antidepressant treatment. In addition, a discussion on the potential use of ligands and/or modulators of postsynaptic proteins at the excitatory synapse has been presented.

Magnesium Potentiates the Vortioxetine’s Effects on Physical Performances and Biological Changes in Exercise-Induced Stress in Rats

Background and objectives: Vortioxetine (VRT) is a relatively new selective serotonin reuptake inhibitor (SSRI) antidepressant and serotonin receptor modulator, approved for the treatment of major depression and generalized anxiety disorder. Depression has been linked with psychomotor disengagement, oxidative stress burden and decreased blood levels of brain-derived neurotrophic factor (BDNF). In our study we performed the experimental investigation of VRT, magnesium and of their association on the rats’ endurance capacity, motor behavior and blood biological disturbances in rats subjected to forced exercise in treadmill test. Materials and Methods: The substances were administered orally for 14 consecutive days, as follows: group 1 (control): distilled water 0.3 mL/100 g body; group 2 (Mg): magnesium chloride 200 mg/kg body; group 3 (VRT): VRT 20 mg/kg body; group 4 (VRT+Mg): VRT 20 mg/kg body + magnesium chloride 200 mg/kg body. Magnesium was used as positive control substance with known effects in treadmill test. The consequences of VRT treatment on glucose, cortisol, BDNF and oxidative stress biomarkers (superoxide-dismutase, malondialdehyde, glutathione-peroxidase, lactate dehydrogenase) were also assessed. Results and conclusions: The use of VRT resulted in an improvement in motor capacity and an increase of the rats’ endurance to physical effort. The administration of VRT increased the serum BDNF levels and reduced the oxidative stress in rats subjected to physical effort. The association of magnesium potentiated the effects of VRT on physical performances, the antioxidant activity and the decreasing in serum stress markers in treadmill test in rats.

Zinc Deficiency Blunts the Effectiveness of Antidepressants in the Olfactory Bulbectomy Model of Depression in Rats

Currently used antidepressants do not always provide the desired results, and many patients suffer from treatment-resistant depression. Clinical studies suggest that zinc deficiency (ZnD) may be an important risk factor for depression and might blunt the effect of antidepressants. This study aimed to examine whether ZnD might blunt the effectiveness of antidepressants in the olfactory bulbectomy model (OB) of depression in rats. For this purpose, rats were subjected to the OB model, fed a zinc-deficient diet (3 mg Zn/kg) for 3 weeks, and finally treated with escitalopram (Esc), venlafaxine (Ven) 10 mg/kg, i.p., or combined Esc/Ven (1 mg/kg, i.p.) with zinc (5 mg/kg) for another 3 weeks. Open field (OFT), forced swim (FST), and sucrose intake (SIT) tests were used to evaluate depressive-like behavioral changes. In addition, serum, intracellular, and synaptic Zn concentrations and the level of zinc transporter (ZnT) proteins were analyzed. The OB + ZnD model induced hyperactivity in rats in the OFT, increased immobility time in the FST, and anhedonia in the SIT. Chronic treatment with Esc reduced immobility time in the FST in the OB + ZnD model. Esc/Ven +Zn increased sucrose intake in rats from the OB + ZnD group. The OB + ZnD decreased serum zinc levels and intracellular and synaptic Zn concentration in the prefrontal cortex (PFC) and cerebellum. These changes were normalized by chronic administration of Esc/Ven +Zn. Moreover, OB + ZnD decreased levels of the ZnT1 protein in the PFC and Hp and ZnT3 in Hp. Chronic administration of antidepressants did not alter the levels of ZnT proteins. The OB + ZnD model induces more depressive-like effects than either model alone. Our results show that ZnD may induce drug resistance in rats. Normalizing serum or brain zinc concentration is insufficient to reverse behavioral abnormalities caused by the OB + ZnD model. However, zinc supplementation might improve the effectiveness of antidepressants in reversing particular depression symptoms.

The Presence of Blood-Brain Barrier Modulates the Response to Magnesium Salts in Human Brain Organoids

Magnesium (Mg) is fundamental in the brain, where it regulates metabolism and neurotransmission and protects against neuroinflammation. To obtain insights into the molecular basis of Mg action in the brain, we investigated the effects of Mg in human brain organoids, a revolutionary 3D model to study neurobiology and neuropathology. In particular, brain organoids derived from human induced pluripotent stem cells were cultured in the presence or in the absence of an in vitro-generated blood–brain barrier (BBB), and then exposed to 1 or 5 mM concentrations of inorganic and organic Mg salts (Mg sulphate (MgSO₄); Mg pidolate (MgPid)). We evaluated the modulation of NMDA and GABAergic receptors, and BDNF. Our data suggest that the presence of the BBB is essential for Mg to exert its effects on brain organoids, and that 5 mM of MgPid is more effective than MgSO₄ in increasing the levels of GABA receptors and BDNF, and decreasing those of NMDA receptor. These results might illuminate novel pathways explaining the neuroprotective role of Mg.

Are Essential Trace Elements Effective in Modulation of Mental Disorders? Update and Perspectives

The emergence of mental disorders is associated with several risk factors including genetic and environmental susceptibility. A group of nutrients serves an especially important role in a number of essential neurodevelopmental processes through brain areas promoting the high degree of brain metabolism during early life, although almost all nutrients are needed. These include macronutrients and micronutrients (e.g., iron, magnesium, zinc, copper, selenium). Numerous nutritional psychiatry trials have been performed to examine the correlation of many individual nutrients with mental health, such as essential trace elements. The increased accumulation or lack of such components will facilitate an alternative metabolic pathway that can lead to many diseases and conditions of neurodevelopment. Mental functions have biochemical bases, so the impairment of such neurochemical mechanisms due to lack of trace elements can have mental effects. In psychological conditions such as depression, anxiety, schizophrenia, and autism, scientific studies demonstrate the putative role of trace element deficiency. Therefore, given the critical roles played by essential trace elements in the neurodevelopment and mental health, the effect of these elements' intake on the modulation of psychological functioning is reviewed.

Antidepressant-like Effects of Combined Fluoxetine and Zinc Treatment in Mice Exposed to Chronic Restraint Stress Are Related to Modulation of Histone Deacetylase

Chronic stress is the key factor contributing to the development of depressive symptoms. Chronic restraint stress (CRS) is well validated and is one of the most commonly used models to induce depressive-like behavior in rodents. The present study aimed to evaluate whether fluoxetine (FLU 5 mg/kg) and zinc (Zn 10mg/kg) given simultaneously induce a more pronounced antidepressant-like effect in the CRS model than both those compounds given alone. Behavioral assessment was performed using the tail suspension and splash tests (TST and ST, respectively). Furthermore, the effects of CRS, FLU and Zn given alone and combined treatment with FLU + Zn on the expression of proteins involved in the apoptotic, inflammatory, and epigenetic processes were evaluated in selected brain structures (prefrontal cortex, PFC; and hippocampus, Hp) using Western blot analysis or enzyme-linked immunosorbent assays (ELISA). The results obtained indicated that three hours (per day) of immobilization for 4 weeks induced prominent depressive symptoms that manifested as increased immobility time in the TST, as well as decreased number and grooming time in the ST. Behavioral changes induced by CRS were reversed by both FLU (5 and 10 mg/kg) or Zn (10 mg/kg). Zinc supplementation (10 mg/kg) slightly increases the effectiveness of FLU (5 mg/kg) in the TST. However, it significantly increased the activity of FLU in the ST compared to the effect induced by FLU and Zn alone. Biochemical studies revealed that neither CRS nor FLU and Zn given alone or in combined treatment alter the expression of proteins involved in apoptotic or inflammatory processes. CRS induced major alterations in histone deacetylase (HDAC) levels by increasing the level of HADC1 and decreasing the level of HADC4 in the PFC and Hp, decreasing the level of HADC6 in the PFC but increasing it in Hp. Interestingly, FLU + Zn treatment reversed CRS-induced changes in HDAC levels in the Hp, indicating that HDAC modulation is linked to FLU + Zn treatment and this effect is structure-specific.

Pharmaco-Electroencephalography-Based Assessment of Antidepressant Drug Efficacy-The Use of Magnesium Ions in the Treatment of Depression

Pharmaco-electroencephalography (pharmaco-EEG) is a technique used to assess the effects of psychotropic medications on the bioelectrical activity of the brain. The purpose of this study was to assess the treatment response with the use of the Hamilton Depression Rating Scale (HDRS) and via EEG. Over an 8-week period, we analyzed electroencephalographic tracings of 91 patients hospitalized for major depression at the Medical University of Warsaw. Thirty-nine of those patients received tricyclic antidepressants (TCAs), 35 received fluoxetine, and 17 received fluoxetine augmented with magnesium (Mg) ions. All patients had their serum drug levels monitored. The highest proportion of patients (88.2%) who showed adequate responses to treatment was observed in the fluoxetine+Mg group, whereas the lowest rates of treatment response were observed in the TCA group (58.3%). This difference was statistically significant (p = 0.029, Phi = 0.30). Our study demonstrated a relationship between achieving remission (HDRS ≤ 6 at week 8 of treatment) and obtaining a positive pharmaco-EEG profile 6 h after administration of the first dose in the group receiving fluoxetine augmented with Mg ions (p = 0.035, Phi = 0.63).

Randomized study of the effects of vitamin D and/or magnesium supplementation on mood, serum levels of BDNF, inflammation, and SIRT1 in obese women with mild to moderate depressive symptoms

OBJECTIVES

This study aimed to evaluate the effects of vitamin D and/or magnesium supplementation on mood, serum levels of BDNF, inflammation, and SIRT1 in obese women with mild to moderate depressive symptoms.

METHODS

In this trial, the 108 obese women with mild to moderate depressive symptoms were randomly allocated into 4 groups: (1) co- supplementation group (n = 27): receiving a 50000 IU vitamin D soft gel weekly + a 250- mg magnesium tablet daily; (2) vitamin D group (n = 27): receiving a 50000 IU vitamin D soft gel weekly + a magnesium placebo daily; (3) magnesium group (n = 27): receiving a vitamin D placebo weekly + a 250- mg magnesium tablet daily; (4) control group (n = 27): receiving a vitamin D placebo weekly + a magnesium placebo daily, for 8 weeks. Before and after the intervention, anthropometric indices, depressive symptoms, serum levels of BDNF, 25(OH)-D, inflammation, and SIRT1, were measured.

RESULTS

At the end of the study, ANCOVA demonstrated significant differences between the 4 groups in 25(OH)-D, magnesium, TNF-α, IL-6, and BDNF levels. But, we found no significant differences in terms of hs-CRP and SIRT1 levels. A significant reduction in depression score was observed in 3 intervention groups and also in control group. No significant differences in BDI-II score were shown among the 4 groups at the end of the intervention.

CONCLUSION

Vitamin D plus magnesium supplementation in obese women with mild to moderate depressive symptoms has beneficial influences on mood, serum levels of BDNF, inflammation, and SIRT1.

The effects of wheat germ consumption on mental health and brain-derived neurotrophic factor in subjects with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial

Objectives: Herbals, as bioactive foods, have been one of the most popular alternatives and complementary treatments in preventing and controlling type 2 diabetes mellitus (T2DM). The aim of the present trial was to examine the effects of wheat germ consumption on mental health and brain-derived neurotrophic factor (BDNF) among patients with T2DM.Methods: Eighty participants with T2DM were randomly allocated to receive 20 g wheat germ (n = 40) or placebo (n = 40) in a randomized double-blind clinical trial for 12 weeks. Depression, anxiety, stress scale-21 (DASS-21) questionnaire was used to assess the mental health of study participants. Serum BDNF was assessed at the baseline and end of intervention. Anthropometric indices were measured at the baseline, 6 and 12 weeks during the intervention.Results: A total of 75 subjects completed the trial. Compared with the placebo, wheat germ consumption led to a significant reduction in depression (P = .03) and stress (P = .04) scores. Moreover, a significant increase in serum BDNF concentrations was observed in the wheat germ group (P = .004), while there was no significant difference between the groups. Wheat germ intake had no significant effects on anthropometric indices and anxiety scores between the groups.Conclusion: Our findings showed that wheat germ consumption for 12 weeks could significantly reduce the stress and depression scores but had no significant effects on anxiety scale and anthropometric outcomes in patients with T2DM.

The effects of magnesium supplementation on serum level of brain derived neurotrophic factor (BDNF) and depression status in patients with depression

OBJECTIVE

Recent researches suggest that there is a relationship between the pathogenesis of depression and serum Brain Derived Neurotrophic Factor (BDNF) levels. Therefore, the purpose of this clinical trial was to determine effect of magnesium supplementation on serum Level of BDNF, magnesium and depression status in patients with depression.

METHODS

A double blind randomized clinical trial was conducted on 46 depressed subjects. The participants were randomly allocated into the magnesium (MG) and the placebo (PG) group and received 500 mg magnesium and placebo daily for 8 weeks. Beck's test was conducted and blood samples were taken at baseline and after the intervention period for analysis of serum magnesium and BDNF.

RESULTS

No significant differences were observed in assessed variables between the two groups at the baseline. At the end of intervention, supplementation with magnesium oxide had a significant effect on Beck's test (P = 0.01) and serum magnesium (P = 0.001), but had no significant effect on BDNF levels (P = 0.507) between the two groups.

CONCLUSIONS

Daily intake of 500 mg magnesium oxide for at least 8 weeks improved Beck's test score and serum magnesium in depressed patients, but had no significant effect on BDNF levels between the two groups, Which Further research is recommended.

The Way to a Human's Brain Goes Through Their Stomach: Dietary Factors in Major Depressive Disorder

Globally, more than 250 million people are affected by depression (major depressive disorder; MDD), a serious and debilitating mental disorder. Currently available treatment options can have substantial side effects and take weeks to be fully effective. Therefore, it is important to find safe alternatives, which act more rapidly and in a larger number of patients. While much research on MDD focuses on chronic stress as a main risk factor, we here make a point of exploring dietary factors as a somewhat overlooked, yet highly promising approach towards novel antidepressant pathways. Deficiencies in various groups of nutrients often occur in patients with mental disorders. These include vitamins, especially members of the B-complex (B6, B9, B12). Moreover, an imbalance of fatty acids, such as omega-3 and omega-6, or an insufficient supply with minerals, including magnesium and zinc, are related to MDD. While some of them are relevant for the synthesis of monoamines, others play a crucial role in inflammation, neuroprotection and the synthesis of growth factors. Evidence suggests that when deficiencies return to normal, changes in mood and behavior can be, at least in some cases, achieved. Furthermore, supplementation with dietary factors (so called "nutraceuticals") may improve MDD symptoms even in the absence of a deficiency. Non-vital dietary factors may affect MDD symptoms as well. For instance, the most commonly consumed psychostimulant caffeine may improve behavioral and molecular markers of MDD. The molecular structure of most dietary factors is well known. Hence, dietary factors may provide important molecular tools to study and potentially help treat MDD symptoms. Within this review, we will discuss the role of dietary factors in MDD risk and symptomology, and critically discuss how they might serve as auxiliary treatments or preventative options for MDD.

Magnesium Status and Stress: The Vicious Circle Concept Revisited

Magnesium deficiency and stress are both common conditions among the general population, which, over time, can increase the risk of health consequences. Numerous studies, both in pre-clinical and clinical settings, have investigated the interaction of magnesium with key mediators of the physiological stress response, and demonstrated that magnesium plays an inhibitory key role in the regulation and neurotransmission of the normal stress response. Furthermore, low magnesium status has been reported in several studies assessing nutritional aspects in subjects suffering from psychological stress or associated symptoms. This overlap in the results suggests that stress could increase magnesium loss, causing a deficiency; and in turn, magnesium deficiency could enhance the body’s susceptibility to stress, resulting in a magnesium and stress vicious circle. This review revisits the magnesium and stress vicious circle concept, first introduced in the early 1990s, in light of recent available data.

Ablation of olfactory bulb glutamatergic neurons induces depressive-like behaviors and sleep disturbances in mice

RATIONALE

Major depression is a serious, but common, psychological disorder, which consists of a long-lasting depressive mood, feelings of helplessness, anhedonia, and sleep disturbances. It has been reported that rats with bilateral olfactory bulbectomies (OBXs) exhibit depressive-like behaviors which indicates that the olfactory bulb (OB) plays an important role in the formation of depression. However, which type of OB neurons plays an important role in the formation of depression remains unclear.

OBJECTIVE

To determine the role of OB neuronal types in depression and related sleep-wake dysfunction.

METHODS

Firstly, we established and evaluated a conventional physical bilateral OBX depression model. Secondly, we used chemical methods to ablate OB neurons, while maintaining the original shape, and evaluated depressive-like behaviors. Thirdly, we utilized AAV-flex-taCasp3-TEVp and transgenetic mice to specifically ablate the OB GABAergic or glutamatergic neurons, then evaluated depressive-like behaviors.

RESULTS

Compared with measured parameters in sham mice, mice with OBXs or ibotenic acid-induced OB lesions exhibited depressive-like behaviors and sleep disturbances, as demonstrated by results of depressive-like behavior tests and sleep recordings. Selective lesioning of OB glutamatergic neurons, but not GABAergic neurons induced depressive-like behaviors and increased rapid eye movement sleep during the light phase of the circadian cycle.

CONCLUSIONS

These results indicate that OB glutamatergic neurons play a key role in olfactory-related depression and sleep disturbance.

S 47445 counteracts the behavioral manifestations and hippocampal neuroplasticity changes in bulbectomized mice

S 47445 is a positive allosteric modulator of glutamate AMPA-type receptors that possesses procognitive, neurotrophic and enhancing synaptic plasticity properties. Its chronic administration promotes antidepressant- and anxiolytic-like effects in different rodent models of depression. We have evaluated the behavioral effects of S 47445 in the bilateral olfactory bulbectomy mice model (OB) and the adaptive changes in those proteins associated to brain neuroplasticity (BDNF and mTOR pathway). Following OB surgery, adult C57BL/6J male mice were chronically administered S 47445 (1, 3 and 10 mg/kg/day; i.p.) and fluoxetine (18 mg/kg/day; i.p.), and then behaviorally tested in the open field test. Afterwards, the expression levels of BDNF, mTOR, phospho-mTOR, 4EBP1 and phospho-4EBP1 were evaluated in hippocampus and prefrontal cortex. Both drugs reduced the OB-induced locomotor activity, a predictive outcome of antidepressant efficacy, with a similar temporal pattern of action. S 47445, but not fluoxetine, showed an anxiolytic effect as reflected by an increased central activity. Chronic administration of S 47445 reversed OB-induced changes in BDNF and phopho-mTOR expression in hippocampus but not in prefrontal cortex. The chronic administration of S 47445 induced antidepressant- and anxiolytic-like effects at low-medium doses (1 and 3 mg/kg/day, i.p.) associated with the reversal of OB-induced changes in hippocampal BDNF and mTOR signaling pathways.

Effects of Magnesium Supplementation on Unipolar Depression: A Placebo-Controlled Study and Review of the Importance of Dosing and Magnesium Status in the Therapeutic Response

Animal studies using tests and models have demonstrated that magnesium exerts an antidepressant effect. The literature contains few studies in humans involving attempts to augment antidepressant therapy with magnesium ions. The purpose of our study was to assess the efficacy and safety of antidepressant treatment, in combination with magnesium ions. A total of 37 participants with recurrent depressive disorder who developed a depressive episode were included in this study. As part of this double-blind study, treatment with the antidepressant fluoxetine was accompanied with either magnesium ions (120 mg/day as magnesium aspartate) or placebo. During an 8-week treatment period, each patient was monitored for any clinical abnormalities. Moreover, serum fluoxetine and magnesium levels were measured, and pharmaco-electroencephalography was performed. The fluoxetine + magnesium and fluoxetine + placebo groups showed no significant differences in either Hamilton Depression Rating Scale (HDRS) scores or serum magnesium levels at any stage of treatment. Multivariate statistical analysis of the whole investigated group showed that the following parameters increased the odds of effective treatment: lower baseline HDRS scores, female gender, smoking, and treatment augmentation with magnesium. The parameters that increased the odds of remission were lower baseline HDRS scores, shorter history of disease, the presence of antidepressant-induced changes in the pharmaco-EEG profile at 6 h after treatment, and the fact of receiving treatment augmented with magnesium ions. The limitation of this study is a small sample size.

Naringenin protects against oxido-inflammatory aberrations and altered tryptophan metabolism in olfactory bulbectomized-mice model of depression

Oxido-inflammatory aberrations play a substantial role in the pathophysiology of depression. Oxido-inflammatory stress increases catabolism of tryptophan into kynurenine which leads to imbalance in kynurenine and serotonin levels in the brain. Naringenin a flavonoid, has been reported to possess antidepressant property by restoring serotonin and noradrenaline levels in the brain. Its effects on oxido-inflammatory aberrations in depression has not been investigated. With this background, the present study was designed to investigate the antidepressant-like potential of naringenin in olfactory bulbectomy (OBX)-induced neuroinflammation, oxidative stress, altered kynurenine pathway, and behavioural deficits in BALB/c mice. OBX-mice showed depression-like behavioural alterations characterized by hyperactivity in open field, increased immobility time in forced swim test and decreased sucrose preference. After 14 days, OBX-mice were treated by gavage with naringenin (25, 50 and 100 mg/kg) and fluoxetine (5 mg/kg) for two weeks. Naringenin significantly ameliorated depression-like behavioural alterations. Naringenin significantly restored corticosterone levels in serum and antioxidant enzymes (Catalase, SOD GSH), nitrite and MDA in cerebral cortex and hippocampus showing its anti-stress and antioxidant property. Naringenin also significantly decreased elevated pro-inflammatory cytokines like IL-1β, IL-6, TNF-α and NF-ҝβ levels. Naringenin also significantly increased neurotrophic growth factor like BDNF. Naringenin reversed altered levels of tryptophan, serotonin, 5-Hydroxyindole acetic acid and kynurenine in hippocampus and cortex. A positive correlation was found between KYN/TRP ratio and proinflammatory parameters while endogenous antioxidants were negatively correlated. In conclusion, naringenin showed potent neuroprotective effect in depression comparable to the fluoxetine by restoring alterations in kynurenine pathway via its antioxidant and anti-inflammatory potential.

Zinc, Magnesium, Selenium and Depression: A Review of the Evidence, Potential Mechanisms and Implications

Micronutrient deficiency and depression are major global health problems. Here, we first review recent empirical evidence of the association between several micronutrients—zinc, magnesium, selenium—and depression. We then present potential mechanisms of action and discuss the clinical implications for each micronutrient. Collectively, empirical evidence most strongly supports a positive association between zinc deficiency and the risk of depression and an inverse association between zinc supplementation and depressive symptoms. Less evidence is available regarding the relationship between magnesium and selenium deficiency and depression, and studies have been inconclusive. Potential mechanisms of action involve the HPA axis, glutamate homeostasis and inflammatory pathways. Findings support the importance of adequate consumption of micronutrients in the promotion of mental health, and the most common dietary sources for zinc and other micronutrients are provided. Future research is needed to prospectively investigate the association between micronutrient levels and depression as well as the safety and efficacy of micronutrient supplementation as an adjunct treatment for depression.

The level of the zinc homeostasis regulating proteins in the brain of rats subjected to olfactory bulbectomy model of depression

BACKGROUND

Zinc transporters (ZnTs) and metallothioneins (MT) are important in maintaining Zn homeostasis in the brain. The present study was designed to find out whether alterations in ZnTs and MTs are associated with the pathophysiology of depression and the mechanism of antidepressant action.

METHODS

Messenger RNA and proteins of ZnT1, ZnT3, ZnT4, ZnT5, ZnT6 and MT1/2 were measured in the prefrontal cortex (PFC) and hippocampus (Hp) of rats subjected to olfactory bulbectomy (OB) (a model of depression) and chronic amitriptyline (AMI) treatment by Real Time PCR and Western Blot/Immunohistochemistry (IHP).

RESULTS

Results in the OB rats showed: increases in the protein levels of ZnT1 in the PFC and Hp and MT1/2 in the PFC; a decrease in ZnT3 protein level in the PFC; no changes in ZnT4, ZnT5 and ZnT6 in the PFC and Hp. IHP labeling revealed increases in the optical densities of ZnT1-IR in the PFC and Hp and decreases in ZnT3 and ZnT4-IR in the PFC of OB rats. Although OB had no effects on gene expression of ZnTs, mRNAs for MT1/2 were increased. Chronic AMI treatment did not influence protein levels of ZnTs and MT1/2 in Sham and OB rats; however decreased mRNA levels of ZnT4 and ZnT5 in PFC and ZnT1, ZnT3, ZnT4 and ZnT6 in Hp of Sham rats and normalized OB induced increase in MT1/2 gene expression.

CONCLUSIONS

Changes in ZnTs and MT1/2 suggest altered cortical distribution of Zn in the OB model which further supports the hypothesis that Zn dyshomeostasis may be involved in the pathophysiology of depression.

Rapamycin blocks the antidepressant effect of ketamine in task-dependent manner

OBJECTIVE

The aim of our study was to test whether ketamine produces an antidepressant effect in animal model of olfactory bulbectomy and assess the role of mammalian target of rapamycin (mTOR) pathway in ketamine's antidepressant effect.

METHODS

Bulbectomized (OBX) rats and sham controls were assigned to four subgroups according to the treatment they received (ketamine, saline, ketamine + rapamycin, and saline + rapamycin). The animals were subjected to open field (OF), elevated plus maze (EPM), passive avoidance (PA), Morris water maze (MWM), and Carousel maze (CM) tests. Blood samples were collected before and after drug administration for analysis of phosphorylated mTOR level. After behavioral testing, brains were removed for evaluation of brain-derived neurotrophic factor (BDNF) in prefrontal cortex (PFC) and hippocampus.

RESULTS

Ketamine normalized hyperactivity of OBX animals in EPM and increased the time spent in open arms. Rapamycin pretreatment resulted in elimination of ketamine effect in EPM test. In CM test, ketamine + rapamycin administration led to cognitive impairment not observed in saline-, ketamine-, or saline + rapamycin-treated OBX rats. Prefrontal BDNF content was significantly decreased, and level of mTOR was significantly elevated in OBX groups.

CONCLUSIONS

OBX animals significantly differed from sham controls in most of the tests used. Treatment had more profound effect on OBX phenotype than controls. Pretreatment with rapamycin eliminated the anxiolytic and antidepressant effects of ketamine in task-dependent manner. The results indicate that ketamine + rapamycin application resulted in impaired stress responses manifested by cognitive deficits in active place avoidance (CM) test. Intensity of stressor (mild vs. severe) used in the behavioral tests had opposite effect on controls and on OBX animals.

Brain glutamic acid decarboxylase-67kDa alterations induced by magnesium treatment in olfactory bulbectomy and chronic mild stress models in rats

BACKGROUND

The preclinical results indicate that magnesium, an N-methyl-d-aspartate receptor (NMDAR) blocker has anxiolytic and antidepressant-like activity. One of the mechanisms involved in these activities is modulation of glutamate, γ-aminobutyric acid (GABA) system. Based on this, the aim of the present study was to investigate the effect of magnesium on the level of glutamic acid decarboxylase-67kDa (GAD-67) in the different brain areas in the chronic mild stress (CMS) and olfactory bulbectomy (OB) models of depression in rats.

METHODS

Magnesium (15mg/kg) was administered intraperitonealy once daily for 14 days in the OB model and for 35 days in the CMS model. 24h after the last dose, the prefrontal cortex (PFC), hippocampus and amygdala were collected and the GAD-67 protein level was determined by the western blotting method.

RESULTS

In the OB model, chronic magnesium treatment normalized decreased by OB protein level of GAD-67 in PFC. CMS did not influence the GAD-67 protein level, however magnesium increased GAD-67 protein expression in amygdala and PFC of stress rats when compared to vehicle-treated stress group. OB or CMS models as well as magnesium treatment did not affect GAD-67 protein level in the hippocampus.

CONCLUSIONS

Obtained results indicate that the antidepressant-like activity of magnesium in CMS and OB models of depression is associated with an enhanced expression of GAD-67 in the PFC and amygdala.

Dietary magnesium intake and the incidence of depression: A 20-year follow-up study

BACKGROUND

Depression is a major global public health concern. The aetiology of depression is partly unclear; however, intake of nutrients, such as magnesium, have been suggested to affect depressive symptoms and modify depression risk.

METHODS

This research is a part of the Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, conducted on a sample of 2320 Eastern Finnish men aged 42-61 years old at the baseline. Magnesium intake was assessed by a 4-day food record. Hospital discharge diagnosis of unipolar depressive disorder was used as an outcome variable.

RESULTS

Participants in the middle tertile of dietary magnesium intake had a statistically significantly decreased risk of getting a hospital discharge diagnosis of depression compared to participants in the lowest tertile of magnesium intake (HR 0.49, CI 0.25-0.95, P=0.035) in the prospective setting after multivariable adjustments. In addition, an inverse association between magnesium intake and the risk of depression was found when the combined middle and highest tertiles of magnesium intake were compared with the lowest tertile (HR 0.53, CI 0.29-0.95, P=0.033).

LIMITATIONS

Our findings may not be generalizable to individuals below middle-age or women. Moreover, we were unable to consider cases with mild depression in the longitudinal setting.

CONCLUSIONS

The results of this study suggest that magnesium intake may have an effect on the risk to develop depression. Further studies are needed to investigate whether sufficient magnesium intake could have implications for prevention or treatment of depression.

Olfactory bulbectomy-induced changes in phospholipids and protein profiles in the hippocampus and prefrontal cortex of rats. A preliminary study using a FTIR spectroscopy

BACKGROUND

Dysfunctions in neuronal proteins can lead to development of depression. Lipids determine the localization and function of proteins in the cell membrane and thereby regulate synaptic throughput in neurons. The aim of study was to examine changes in the phospholipid-protein balance in the olfactory bulbectomy (OB) model of depression in rats using a Fourier transform infra-red (FTIR) spectroscopy.

METHODS

Sprague Dawley rats were subjected to the OB procedure and treated with amitriptyline (AMI, 10mg/kg). The FTIR measurements were performed in the hippocampus and prefrontal cortex.

RESULTS

The obtained results show a decrease in the phospholipids and protein fractions (as well as changes in their secondary structures) in both brain areas of bulbectomized rats. AMI treatment reduced phospholipids' and increased the proteins' brain level, yet did not affect the level of phospholipids or increase the proteins in OB rats. Second derivatives calculated from the FTIR spectra provided information that the proteins (but not phospholipids) in both structures of the OB_AMI rats were normalized after antidepressant treatment.

CONCLUSIONS

Our findings prove that the changes in the phospholipid-protein balance in the hippocampus and prefrontal cortex may be related to depressive disorders, thus leading to the development of adverse changes in the molecules necessary for the correct functioning of the brain. Furthermore, these results suggest a stability of the structure changes/damage of phospholipids in depression, which are present in brain tissues even after effective pharmacotherapy. This study also shows that an infrared spectroscopy can be applied for monitoring changes in mood disorders.

The role of glutamatergic, GABA-ergic, and cholinergic receptors in depression and antidepressant-like effect

Depression is one of the most common mental disorders and social issue worldwide. Although there are many antidepressants available, the effectiveness of the therapy is still a serious issue. Moreover, there are many limitations of currently used antidepressants, including slow onset of action, numerous side effects, or the fact that many patients do not respond adequately to the treatment. Therefore, scientists are searching for new compounds with different mechanisms of action. Numerous data indicate the important role of glutamatergic, GABA-ergic, and cholinergic receptors in the pathomechanism of major depressive disorder. This review presents the role of glutamatergic, GABA-ergic, and cholinergic receptors in depression and antidepressant-like effect.