Monosodium glutamate, a food additive, induces depressive-like and anxiogenic-like behaviors in young rats

Biomarkers Associated with Depression Improvement in Veterans with Gulf War Illness Using the Low-Glutamate Diet

Gulf War Illness (GWI) is a chronic multi-symptom neurological disorder affecting veterans of the Gulf War that is commonly comorbid with depression. A secondary data analysis was conducted to examine serum homocysteine and inflammatory cytokines (IFN-γ, IL-6, IL-1β, TNF-α) as potential biomarkers of depression improvement among veterans with GWI after a one-month dietary intervention aimed at reducing excitotoxicity and increasing micronutrients. Analyses, including multiple linear and logistic regression, were conducted in R studio. Dietary adherence was estimated using a specialized excitotoxin food frequency questionnaire (FFQ), and depression was measured using the Center for Epidemiologic Studies Depression (CES-D) scale. After one month on the diet, 52% of participants reported a significant decrease in depression (p < 0.01). Greater dietary adherence (FFQ) was associated with increased likelihood of depression improvement; OR (95% CI) = 1.06 (1.01, 1.11), (p = 0.02). Reduced homocysteine was associated with depression improvement after adjusting for FFQ change (β = 2.58, p = 0.04), and serum folate and vitamin B12 were not mediators of this association. Reduction in IFN-γ was marginally associated with likelihood of depression improvement (OR (95% CI) = 1.11 (0.00, 1.42), (p = 0.06)), after adjustment for potential confounders. Findings suggest that homocysteine, and possibly IFN-γ, may serve as biomarkers for depression improvement in GWI. Larger trials are needed to replicate this work.

Association between junk food consumption and mental health problems in adults: a systematic review and meta-analysis

BACKGROUND

Anxiety and depression can seriously undermine mental health and quality of life globally. The consumption of junk foods, including ultra-processed foods, fast foods, unhealthy snacks, and sugar-sweetened beverages, has been linked to mental health. The aim of this study is to use the published literature to evaluate how junk food consumption may be associated with mental health disorders in adults.

METHODS

A systematic search was conducted up to July 2023 across international databases including PubMed/Medline, ISI Web of Science, Scopus, Cochrane, Google Scholar, and EMBASE. Data extraction and quality assessment were performed by two independent reviewers. Heterogeneity across studies was assessed using the I2 statistic and chi-square-based Q-test. A random/fixed effect meta-analysis was conducted to pool odds ratios (ORs) and hazard ratios (HRs).

RESULTS

Of the 1745 retrieved articles, 17 studies with 159,885 participants were suitable for inclusion in the systematic review and meta-analysis (seven longitudinal, nine cross-sectional and one case-control studies). Quantitative synthesis based on cross-sectional studies showed that junk food consumption increases the odds of having stress and depression (OR = 1.15, 95% CI: 1.06 to 1.23). Moreover, pooling results of cohort studies showed that junk food consumption is associated with a 16% increment in the odds of developing mental health problems (OR = 1.16, 95% CI: 1.07 to 1.24).

CONCLUSION

Meta-analysis revealed that consumption of junk foods was associated with an increased hazard of developing depression. Increased consumption of junk food has heightened the odds of depression and psychological stress being experienced in adult populations.

Diet's Impact on Post-Traumatic Brain Injury Depression: Exploring Neurodegeneration, Chronic Blood-Brain Barrier Destruction, and Glutamate Neurotoxicity Mechanisms

Traumatic brain injury (TBI) has a profound impact on cognitive and mental functioning, leading to lifelong impairment and significantly diminishing the quality of life for affected individuals. A healthy blood-brain barrier (BBB) plays a crucial role in guarding the brain against elevated levels of blood glutamate, making its permeability a vital aspect of glutamate regulation within the brain. Studies have shown the efficacy of reducing excess glutamate in the brain as a treatment for post-TBI depression, anxiety, and aggression. The purpose of this article is to evaluate the involvement of dietary glutamate in the development of depression after TBI. We performed a literature search to examine the effects of diets abundant in glutamate, which are common in Asian populations, when compared to diets low in glutamate, which are prevalent in Europe and America. We specifically explored these effects in the context of chronic BBB damage after TBI, which may initiate neurodegeneration and subsequently have an impact on depression through the mechanism of chronic glutamate neurotoxicity. A glutamate-rich diet leads to increased blood glutamate levels when contrasted with a glutamate-poor diet. Within the context of chronic BBB disruption, elevated blood glutamate levels translate to heightened brain glutamate concentrations, thereby intensifying neurodegeneration due to glutamate neurotoxicity.

Experimental evidence of the neurotoxic effect of monosodium glutamate in adult female Sprague Dawley rats: The potential protective role of Zingiber officinale Rosc. rhizomes

Strategies to prevent the health abnormalities associated with the extensive use of MSG (monosodium glutamate) as a flavoring booster are badly needed. The current study was conducted to investigate oxidative stress, inflammation, and abnormal lipid profile as the main risk factors of neurotoxicity in MSG-exposed female albino rats. Besides, the effect of concurrent consumption of Zingiber officinale rhizomes powder was studied at low doses. Twenty rats (total) were split into 4 separate groups. The 1st group was a negative control group (without any treatment), while the others received 6 mg MSG/kg. The 2nd group was left untreated, whereas the 3rd and 4th groups were given a regular laboratory diet that included ginger rhizome powder supplements (GRP, 0.5 & 1%, respectively) for six weeks. In brain tissue homogenates, exposure to MSG caused a significant depletion of gamma-aminobutyric acid (GABA) and total protein levels, while triglycerides and cholesterol contents were significantly elevated. Moreover, a noteworthy upsurge in oxidative load and inflammation markers was also noticed associated with a marked reduction of antioxidant levels, which histopathological staining verified further. The rat diet formulated with GRP, with a dose-dependent effect, resulted in increased GABA and total protein contents and attenuated inflammation, oxidative stress, abnormal lipid profile, and marked histological changes in cerebral cortical neurons of MSG-administered animals. Therefore, this study reveals that GRP shields rats against the neurotoxicity that MSG causes. The anti-inflammatory as well as antioxidant, and lipid-normalizing properties of rhizomes of ginger may be accountable for their observed neuroprotective action.

Possible Signaling Pathways in the Gut Microbiota-Brain Axis for the Development of Parkinson's Disease Caused by Chronic Consumption of Food Additives

It is well-known that consumption of synthetic and natural food additives has both positive and negative effects in the human body. However, it is not clear yet how food additives are related to the development of Parkinson's disease. Therefore, in this review work, the food additive effects related to the gut microbiota-brain axis and the processes that are carried out to develop Parkinson's disease are studied. To this end, a systematic literature analysis is performed with the selected keywords and the food additive effects are studied to draw possible routes of action. This analysis leads to the proposition of a model that explains the pathways that relate the ingestion of food additives to the development of Parkinson's disease. This work motivates further research that ponders the safety of food additives by measuring their impacts over the gut microbiota-brain axis.

High ultra-processed food consumption is associated with elevated psychological distress as an indicator of depression in adults from the Melbourne Collaborative Cohort Study

BACKGROUND

Few studies have tested longitudinal associations between ultra-processed food consumption and depressive outcomes. As such, further investigation and replication are necessary. The aim of this study is to examine associations of ultra-processed food intake with elevated psychological distress as a marker for depression after 15 years.

METHOD

Data from the Melbourne Collaborative Cohort Study (MCCS) were analysed (n = 23,299). We applied the NOVA food classification system to a food frequency questionnaire (FFQ) to determine ultra-processed food intake at baseline. We categorised energy-adjusted ultra-processed food consumption into quartiles by using the distribution of the dataset. Psychological distress was measured by the ten-item Kessler Psychological Distress Scale (K10). We fitted unadjusted and adjusted logistic regression models to assess the association of ultra-processed food consumption (exposure) with significant psychological distress (outcome and defined as K10 ≥ 20). We fitted additional logistic regression models to determine whether these associations were modified by sex, age and body mass index.

RESULTS

After adjusting for sociodemographic characteristics and lifestyle and health-related behaviours, participants with the highest relative intake of ultra-processed food were at increased odds of significant psychological distress compared to participants with the lowest intake (aOR: 1.23; 95%CI: 1.10, 1.38, p for trend = 0.001). We found no evidence for an interaction of sex, age and body mass index with ultra-processed food intake.

CONCLUSION

Higher ultra-processed food intake at baseline was associated with subsequent elevated psychological distress as an indicator of depression at follow-up. Further prospective and intervention studies are necessary to identify possible underlying pathways, specify the precise attributes of ultra-processed food that confer harm, and optimise nutrition-related and public health strategies for common mental disorders.

Determining the effects of in ovo administration of monosodium glutamate on the embryonic development of brain in chickens

Monosodium glutamate (MSG) is a popular flavor enhancer largely used in the food industry. Although numerous studies have reported the neurotoxic effects of MSG on humans and animals, there is limited information about how it affects embryonic brain development. Thus, this study aimed to determine the effects of in ovo administered MSG on embryonic brain development in chickens. For this purpose, 410 fertilized chicken eggs were divided into 5 groups as control, distilled water, 0.12, 0.6 and 1.2 mg/g egg MSG, and injections were performed via the egg yolk. On days 15, 18, and 21 of the incubation period, brain tissue samples were taken from all embryos and chicks. The mortality rates of MSG-treated groups were significantly higher than those of the control and distilled water groups. The MSG-treated groups showed embryonic growth retardation and various structural abnormalities such as abdominal hernia, unilateral anophthalmia, hemorrhage, brain malformation, and the curling of legs and fingers. The relative embryo and body weights of the MSG-treated groups were significantly lower than those of the control group on incubation days 18 and 21. Histopathological evaluations revealed that MSG caused histopathological changes such as necrosis, neuronophagia, and gliosis in brain on incubation days 15, 18, and 21. There was a significant increase in the number of necrotic neurons in the MSG-treated groups compared to the control and distilled water groups in the hyperpallium, optic tectum and hippocampus regions. Proliferating cell nuclear antigen (PCNA) positive cells in brain were found in the hyperpallium, optic tectum, and hippocampus regions; there were more PCNA(+) immunoreactive cells in MSG-treated groups than in control and distilled water groups. In conclusion, it was determined that in ovo MSG administered could adversely affect embryonic growth and development in addition to causing necrosis in the neurons in the developing brain.

The protective effect of thymoquinone or/and thymol against monosodium glutamate-induced attention-deficit/hyperactivity disorder (ADHD)-like behavior in rats: Modulation of Nrf2/HO-1, TLR4/NF-κB/NLRP3/caspase-1 and Wnt/β-Catenin signaling pathways in rat model

Both thymoquinone (TQ) and thymol (T) have been proved to possess a positive impact on human health. In this research, we aimed to investigate the effect of these compounds separately and together on the Attention-deficit/hyperactivity disorder (ADHD)-like behavior induced by monosodium glutamate (MSG) in rats. Forty male, Spargue Dawley rat pups (postnatal day 21), were randomly allocated into five groups: Normal saline (NS), MSG, MSG+TQ, MSG+T, and MSG+TQ+T. MSG (0.4 mg/kg/day), TQ (10 mg/kg/day) and T (30 mg/kg/day) were orally administered for 8 weeks. The behavioral tests proved that rats treated with TQ and/or T showed improved locomotor, attention and cognitive functions compared to the MSG group with more pronounced effect displayed with their combination. All treated groups showed improvement in MSG-induced aberrations in brain levels of GSH, IL-1β, TNF-α, GFAP, glutamate, calcium, dopamine, norepinephrine, Wnt3a, β-Catenin and BDNF. TQ and/or T treatment also enhanced the mRNA expression of Nrf2, HO-1 and Bcl2 while reducing the protein expression of TLR4, NFκB, NLRP3, caspase 1, Bax, AIF and GSK3β as compared to the MSG group. However, the combined therapy showed more significant effects in all measured parameters. All of these findings were further confirmed by the histopathological examinations. Current results concluded that the combined therapy of TQ and T had higher protective effects than their individual supplementations against MSG-induced ADHD-like behavior in rats.

Neuroprotective Effect of Morin Hydrate against Attention-Deficit/Hyperactivity Disorder (ADHD) Induced by MSG and/or Protein Malnutrition in Rat Pups: Effect on Oxidative/Monoamines/Inflammatory Balance and Apoptosis

Monosodium glutamate (MSG) is one of the most widely used food additives. However, it has been linked to protein malnutrition (PM) and various forms of toxicities such as metabolic disorders and neurotoxic effects. The current study is the first to explore the association between MSG, PM, and induced brain injury similar to attention-deficit/hyperactivity disorder (ADHD). Moreover, we determined the underlying mechanistic protective pathways of morin hydrate (MH)―a natural flavonoid with reported multiple therapeutic properties. PM was induced by feeding animals with a low protein diet and confirmed by low serum albumin measurement. Subsequently, rat pups were randomized into seven groups of 10 rats each. Group I, III, and VI were normally fed (NF) and groups II, IV, V, and VII were PM fed. Group I served as normal control NF while Group II served as PM control animals. Group III received NF + 0.4 g/kg MSG, Group IV: PM + 0.4 g/kg MSG, Group V: PM + 60 mg/kg MH, Group VI: NF + 0.4 kg/g MSG + 60 mg/kg MH and Group VII: PM + 0.4 kg/kg MSG + 60 mg/kg MH. At the end of the experimental period, animals were subjected to behavioral and biochemical tests. Our results showed that treatment of rats with a combination of MSG + PM-fed exhibited inferior outcomes as evidenced by deteriorated effects on behavioral, neurochemical, and histopathological analyses when compared to rats who had received MSG or PM alone. Interestingly, MH improved animals’ behavior, increased brain monoamines, brain-derived neuroprotective factor (BDNF), antioxidant status and protein expression of Nrf2/HO-1. This also was accompanied by a significant decrease in brain MDA, inflammatory markers (NF-kB, TNF-α and IL1β), and suppression of TLR4/NLRP3/caspase-1 axis. Taken together, MSG and/or PM are associated with neuronal dysfunction. Our findings suggest MH as a potential neuroprotective agent against brain insults via targeting Nrf2/HO-1 and hindering TLR4/NLRP3 inflammasome signaling pathways.

Ultra-Processed Food Consumption and Mental Health: A Systematic Review and Meta-Analysis of Observational Studies

Since previous meta-analyses, which were limited only to depression and by a small number of studies available for inclusion at the time of publication, several additional studies have been published assessing the link between ultra-processed food consumption and depression as well as other mental disorders. We aimed to build on previously conducted reviews to synthesise and meta-analyse the contemporary evidence base and clarify the associations between the consumption of ultra-processed food and mental disorders. A total of 17 observational studies were included (n = 385,541); 15 cross-sectional and 2 prospective. Greater ultra-processed food consumption was cross-sectionally associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together (common mental disorder symptoms odds ratio: 1.53, 95%CI 1.43 to 1.63) as well as separately (depressive symptoms odds ratio: 1.44, 95%CI 1.14 to 1.82; and, anxiety symptoms odds ratio: 1.48, 95%CI 1.37 to 1.59). Furthermore, a meta-analysis of prospective studies demonstrated that greater ultra-processed food intake was associated with increased risk of subsequent depression (hazard ratio: 1.22, 95%CI 1.16 to 1.28). While we found evidence for associations between ultra-processed food consumption and adverse mental health, further rigorously designed prospective and experimental studies are needed to better understand causal pathways.

Indole-3-propionic acid mitigates chlorpyrifos-mediated neurotoxicity by modulating cholinergic and redox-regulatory systems, inflammatory stress, apoptotic responses and DNA damage in rats

This study probed the neuroprotective influence of indole-3-propionic acid (IPA) in rats exposed to chlorpyrifos (CPF) alone at 5 mg/kg body weight or co-administered with IPA at 12.5 and 25 mg/kg for 14 days. Behavioral data indicated that IPA significantly (p < 0.05) abated CPF-mediated anxiogenic-like behaviors with concomitant improvement in the locomotor and exploratory behaviors as substantiated by track plots and heat maps data. Also, IPA mitigated CPF-mediated diminution in cholinergic and antioxidant defense systems whereas it markedly improved thioredoxin level and thioredoxin reductase activity in cerebral and cerebellar tissues of the animals. Co-administration of IPA significantly enhanced anti-inflammatory cytokine, interleukin-10 but suppressed oxidative and inflammatory stress, caspase-9 and caspase-3 activation with concomitant reduction in 8-hydroxy-2'-deoxyguanosine (8-OHdG) level and histological damage. Collectively, IPA-mediated neuroprotection involves modulation of cholinergic and redox-regulatory systems, inflammatory stress, apoptotic responses and DNA damage in cerebrum and cerebellum of rats.

Alterations in APC, BECN1, and TP53 gene expression levels in colon cancer cells caused by monosodium glutamate

Colorectal cancer (CRC) is a disease with high incidence worldwide. As of 2018, it is the second leading cause of cancer deaths in the world. In Saudi Arabia, the incidence of this disease has been increasing in the younger population. Both genetic and lifestyle factors may have contributed to its increased incidence and pathogenesis. Monosodium glutamate (MSG) is a food flavor enhancer that can be found in many commercial foods, and it can sometimes be used as a substitute to table salt. MSG has been investigated for its possible genotoxicity, yielding controversial results. In the present study, the effect of MSG on cell viability and its effect on expression of APC, BECN1, and TP53 genes in SW620 and SW480 colon cancer cell lines were studied. TP53 is a tumor suppressor gene that functions in modifying DNA errors and/or inducing apoptosis of damaged cells, and both APC and BECN1 genes are involved in CRC and are of importance in cellular growth and metastasis. Cancer cell viability was analyzed using MTT assay, and the results showed a significant increase in the number of viable cells after 24 h of treatment with MSG with different concentrations (0.5, 1.0, 10, 50, and 100mM). Moreover, gene expression results showed a significant increase in the expression levels of APC and BECN1 under specified conditions in both cell lines; conversely, TP53 showed a significant decrease in expression in SW620 cells. Thus, it can be concluded that MSG possibly confers a pro-proliferative effect on CRC cells.

Microscopic study of potential toxic effects of monosodium glutamate on liver of chicken embryos aged 16 days

Background

This experimental study aimed to determine the changes caused by monosodium glutamate (MSG) on morphology and histology of liver of chicken embryos aged 16 days of incubation. In this research, 50 fertilized eggs were used. They were divided into two equal groups, one group was used as control with normal liver structure, while the other group (MSG) was treated with MSG in 0 day of incubation (0.1ml/egg).

Results

The results showed many harmful effects on hepatic cells, blood sinusoids, and bile ducts in MSG group. These changes included alterations in nuclei conformation and nuclear envelope. Chromatin distribution was associated with increased electronic intensity. Also, there were rupture in smooth endoplasm systems and malfunction of mitochondria and Golgi apparatus, with increased lysosomes and lipid droplets.

Conclusions

This study concluded that MSG had severe toxic effects on liver structure if it was given in pre-conception period as this period is considered critical for liver growth (organogenesis).

Effects of in utero exposure to monosodium glutamate on locomotion, anxiety, depression, memory and KCC2 expression in offspring

In pregnancy, there is a significant risk for developing embryos to be adversely affected by everyday chemicals such as food additives and environmental toxins. In recent times, several studies have documented the detrimental effect of exposure to such chemicals on the behaviour and neurodevelopment of the offspring. This study evaluated the influence of the food additive, monosodium glutamate (MSG), on behaviour and development in mice. Pregnant dams were exposed to MSG 2 or 4 g/kg or distilled water from gestation day 10-20. On delivery, postnatal day 1 (PN 1), 3 pups were sacrificed and whole brain samples assayed for KCC2 expression by western blot. The remaining pups were housed until PN 43 before commencing behavioural assessment. Their weights were measured at birth and at 3 days intervals until PN 42. The impact of prenatal exposure to MSG on baseline exploratory, anxiety and depression behaviours as well as spatial and working memory was assessed. In utero exposure to 4 g/kg MSG significantly reduced exploratory drive and increased depression-like behaviours but did not exert any significant impact on anxiety-like behaviours (p < 0.01). Additionally, there was a two-fold increase in KCC2 expression in both 2 and 4 g/kg MSG-exposed offspring. CONCLUSION: This study indicates that, in utero exposure to MSG increases the expression of KCC2 and causes significant effect on locomotion and depression-like behaviours but only marginally affects memory function.

Glutamate and depression: Reflecting a deepening knowledge of the gut and brain effects of a ubiquitous molecule

The versatility of glutamate as the brain’s foremost excitatory neurotransmitter and modulator of neurotransmission and function is considered common knowledge. Years of research have continued to uncover glutamate’s effects and roles in several neurological and neuropsychiatric disorders, including depression. It had been considered that a deeper understanding of the roles of glutamate in depression might open a new door to understanding the pathological basis of the disorder, improve the approach to patient management, and lead to the development of newer drugs that may benefit more patients. This review examines our current understanding of the roles of endogenous and exogenous sources of glutamate and the glutamatergic system in the aetiology, progression and management of depression. It also examines the relationships that link the gut-brain axis, glutamate and depression; as it emphasizes how the gut-brain axis could impact depression pathogenesis and management via changes in glutamate homeostasis. Finally, we consider what the likely future of glutamate-based therapies and glutamate-based therapeutic manipulations in depression are, and if with them, we are now on the final chapter of understanding the neurochemical milieu of depressive disorders.

The neurotherapeutic role of a selenium-functionalized quinoline in hypothalamic obese rats

RATIONALE

Obesity is considered one of the major global health problems and increases the risk of several medical complications, such as diabetes and mental illnesses.

OBJECTIVE

The present study investigated the effect of 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) on obesity parameters, behavioral and neurochemical alterations in hypothalamic obese rats.

METHODS

Male Wistar rats received subcutaneous neonatal injections of monosodium glutamate (MSG, 4g/kg) or saline. After the Lee Index evaluation, rats were divided into groups and treated with 4-PSQ (5 mg/kg, intragastric route) or canola oil once a day (post-natal days (PND) 60→76). Open-field, elevated plus-maze, forced swim task, object recognition/location memory, and stepdown inhibitory avoidance tasks were conducted from PND 66 to 74. On PND 76, rats were euthanized and epididymal fat, blood, cerebral cortex, andhippocampus were removed. Blood biochemical parameters and cortical/hippocampal acetylcholinesterase (AChE) and Na /K -ATPase activities were assessed.

RESULTS

MSG increased the Lee Index characterizing the chemically induced hypothalamic obesity model. 4-PSQ reversed the increases of epididymal fat, blood glucose, and triglyceride levels caused by MSG exposure. 4-PSQ attenuated anxiety-like and depression-like behaviors induced by neonatal administrations of MSG. Memory deficits found in MSG-obese rats were reversed by treatment with 4-PSQ. Neurochemical alterations produced by MSG evidenced by stimulation ofNa⁺/K⁺-ATPase and AChE activities in the cerebral cortex and hippocampus of rats were normalized by 4-PSQ treatment.

CONCLUSIONS

In brief, 4-PSQ therapy improved hypothalamic obesity-related parameters, as well as psychiatric symptoms, cognitive impairment, and neurochemical alterations found in obese rats.

Modulation of immune functions, inflammatory response, and cytokine production following long-term oral exposure to three food additives; thiabendazole, monosodium glutamate, and brilliant blue in rats

The food additives thiabendazole (TBZ), monosodium glutamate (MSG), and brilliant blue (BB) are commonly used in many daily-consumed food products worldwide. They are widely used in major agricultural and industrial applications. Yet, many of its toxicological aspects are still unclear, especially immune modulation. This research was therefore intended to investigate the effects of male Wistar rats' daily oral exposure for 90 days to TBZ (10 mg/kg b.wt), MSG (20 mg/kg b.wt), or BB (1.2 mg/kg b.wt) on the blood cells, immunity, and inflammatory indicators. The three tested food additives showed varying degrees of hematological alterations. Initially, megaloblastic anemia and thrombocytopenia were evident with the three tested food additives. At the same time, TBZ showed no significant changes in the leukogram element except eosinopenia. MSG induced leukopenia, lymphocytopenia, neutrophilia, and eosinophilia. BB evoked neutrophilia and lymphopenia. The immunoglobins M (IgM) and IgG were significantly reduced with the three tested food additives. In contrast, lysozyme and nitric oxide levels were elevated. A reduced considerably lymphocyte proliferation was detected with TBZ and MSG exposure without affecting the phagocytic activity. Various pathologic disturbances in splenic tissues have been detected. An obvious increase in CD4⁺ but a lessening in CD8⁺ immunolabeling was evident in TBZ and MSG groups. The cytokines, including interferon-gamma, tumor necrosis factor-alpha, and interleukin 1β, 6, 10, and 13, were significantly upregulated in the spleen of rats exposed to TBZ, MSG, and BB. These results concluded that TBZ, MSG, and BB negatively affect hematological parameters, innate and humoral immune functions together with inflammatory responses. TBZ achieved the maximal negative impacts followed by MSG and finally with BB. Given the prevalence of these food additives, TBZ and MSG should be limited to a minimal volume use, or natural food additives should be used instead.

The effects of L-carnitine on renal function and gene expression of caspase-9 and Bcl-2 in monosodium glutamate-induced rats

BACKGROUND

Monosodium glutamate (MSG) is frequently consumed as a flavor enhancer or food additive. Possible damages induced by MSG effects on some organs have been stated in experimental animal models. The aim of the present study was to evaluate the protective effects of L-carnitine (L-ca) on the renal tissue in MSG-Induced Rats.

METHODS

In this regard, 60 male rats were randomly divided into six groups (n = 10/each): 1 (Control); 2 (sham); 3 (L-carnitine 200 mg/kg b.w); 4 (MSG 3 g/kg b.w); 5 (MSG + L-carnitine 100 mg/kg); and 6 (MSG + L-carnitine 200 mg/kg). After 6 months, the rats were sacrificed, the blood sample collected and the kidneys harvested for evaluation of biochemical analytes, genes expression, and histopathological changes.

RESULTS

MSG significantly increased the serum level of MDA, BUN, creatinine, uric acid and renal Caspase-9, NGAL and KIM-1 expression, but it decreased the serum activity also renal expression of SOD, catalase, GPX, and Bcl-2 expression compared to the control group. Treatment with L-ca significantly reduced the serum BUN, creatinine, uric acid and MDA level and increased catalase, GPX and SOD compared to the MSG group. However, only administration of L-ca 200 significantly decreased the caspase-9, NGAL and KIM-1; also, it increased the Bcl-2 expression in the kidney compared to the MSG group.

CONCLUSIONS

Our findings indicated that L-carnitine had a major impact on the cell protection and might be an effective therapy in ameliorating the complications of the kidney induced by MSG via its antioxidant and anti-apoptotic properties.

Neonatal exposure to monosodium glutamate results in impaired auditory brainstem structure and function

Excitotoxic injury during the neonatal period has been shown to result in neurodegenerative changes in several different brain regions. Exposure to monosodium glutamate (MSG) during the first two postnatal weeks results in glutamate neurotoxicity in the cochlea and has been shown to result in damage to cochlear hair cells and fewer neurons in the spiral ganglion. Further, we have shown that such exposure results in fewer neurons in the cochlear nucleus and superior olivary complex and abnormal expression of the calcium binding proteins calbindin and calretinin. Based on these findings, we hypothesized that neonatal MSG exposure would result in loss of neurons at more rostral levels in the auditory brainstem, and this exposure would result in abnormal brainstem auditory evoked potentials. We identified a significantly lower density of neurons in the spiral ganglion, heterogenous loss of neurons in the globular bushy cell-trapezoid body circuit, and fewer neurons in the nuclei of the lateral lemniscus and central nucleus of the inferior colliculus. The most severe loss of neurons was found in the inferior colliculus. Click-evoked auditory brainstem responses revealed significantly higher thresholds and longer latency responses, but these did not deteriorate with age. These results, together with our previous findings, indicate that neonatal exposure to MSG results in fewer neurons throughout the entire auditory brainstem and results in abnormal auditory brainstem responses.

Dietary Glutamic Acid, Obesity, and Depressive Symptoms in Patients With Schizophrenia

Introduction: Schizophrenia is a lifelong condition associated with several comorbid conditions such as physical illnesses like obesity, as well as co-occurring psychiatric symptoms such as depression. Research regarding susceptibility to some of these comorbidities has primary focused on genetic risks or neurotransmitters and very little work has been done to understand environmental factors such as diet. In particular, understanding the role of dietary glutamic acid consumption on co-morbidities in patients with schizophrenia is important, as evidence suggests that glutamic acid consumption may directly influence glutamatergic neurotransmission; a key neurotransmitter related to schizophrenia, its associated co-morbidities, and depression. Therefore, the aim of this study was to examine the potential relationship between dietary glutamic acid and depressive symptomatology in patients with schizophrenia, stratified by obesity status, due to its relationship with inflammation, antipsychotic use, and depressive symptoms. Methods: Subjects included in this analysis, were part of a parent cross-sectional study in which included three dietary recalls analyzed using protocols outlined as part of the National Health and Nutrition Examination Surveys (NHANES) standardized criteria. Additionally, body mass index (BMI), and Beck Depression Inventory were obtained at this visit. Subjects with a BMI ≥ 30 kg/m2 were included in the obesity group, and the relationship between glutamic acid consumption and BDI scores was analyzed after controlling for age, race, sex, antidepressant and antipsychotic use, and animal and vegetable protein intake which provide natural forms of dietary glutamic acid. Results: A total of 168 participants were included in this study, of which 42.5% were female and 52.9% were White. The mean BMI for the group as a whole was 33.5 ± 8.7 (kg/m2) and the mean BDI was 14.5 ± 10.2 (range 2-50). No differences were found between obesity groups, other than a greater hyperlipidemia, hypertension, and lower waist to hip ratio. Overall, no relationship was found between dietary glutamic acid and BDI scores, However, for non-obese participants, diets higher levels of glutamic acid were associated with greater depression symptomatology (p = 0.021). Conclusion: These preliminary results indicate a possible correlation between dietary glutamic acid a depressive symptoms in non-obese patients with schizophrenia, although further research is needed to specifically examine this relationship.

Role of glucocorticoid receptor phosphorylation-mediated synaptic plasticity in anxiogenic and depressive behaviors induced by monosodium glutamate

Psychiatric diseases and metabolic disorders frequently cooccur, yet the mechanisms underlying this interaction remain unknown. The aim of this study was to determine the role of glucocorticoid receptor (GR) phosphorylation in the comorbidity of metabolic and psychiatric disorders. Neonatal Sprague-Dawley rats were subcutaneously injected with monosodium glutamate (MSG) every 2 days for 10 days after birth. Metabolic and behavioral tests were performed 12 weeks later. Golgi staining and transmission electron microscopy (TEM) were performed to evaluate synaptic structural plasticity. Changes in GR phosphorylation and the BDNF/TrkB pathway were evaluated by western blotting and immunofluorescence. We found that MSG-treated rats displayed significant metabolic abnormalities accompanied by anxiogenic and depressive behaviors, an altered synaptic ultrastructure and the loss of dendritic spines. The expression of phosphorylated GR was reduced in the brain. Furthermore, a specific agonist of BDNF/TrkB significantly reversed the reduction in GR phosphorylation, as well as the metabolic and behavioral outcomes. These findings indicate that a decrease in BDNF/TrkB pathway-dependent GR phosphorylation is a long-term effect of MSG treatment that may contribute to metabolic and behavioral disturbances.

Neuroprotective role of gallic acid in aflatoxin B1 -induced behavioral abnormalities in rats

The neurotoxic impact of dietary exposure to aflatoxin B₁ (AFB₁ ) is documented in experimental and epidemiological studies. Gallic acid (GA) is a triphenolic phytochemical with potent anticancer, anti-inflammatory, and antioxidant activities. There is a knowledge gap on the influence of GA on AFB₁ -induced neurotoxicity. This study probed the influence of GA on neurobehavioral and biochemical abnormalities in rats orally treated with AFB₁ per se (75 µg/kg body weight) or administered together with GA (20 and 40 mg/kg) for 28 uninterrupted days. Behavioral endpoints obtained with video-tracking software demonstrated significant (p < .05) abatement of AFB₁ -induced anxiogenic-like behaviors (increased freezing, urination, and fecal bolus discharge), motor and locomotor inadequacies, namely increased negative geotaxis and diminished grip strength, absolute turn angle, total time mobile, body rotation, maximum speed, and total distance traveled by GA. The improvement of exploratory behavior in animals that received both AFB₁ and GA was confirmed by track plots and heat maps appraisal. Abatement of AFB₁ -induced decreases in acetylcholinesterase activity, antioxidant status and glutathione level by GA was accompanied by a marked reduction in oxidative stress markers in the cerebellum and cerebrum of rats. Additionally, GA treatment abrogated AFB₁ -mediated decrease in interleukin-10 and elevation of inflammatory indices, namely tumor necrosis factor-α, myeloperoxidase activity, interleukin-1β, and nitric oxide. Further, GA treatment curtailed caspase-3 activation and histological injuries in the cerebral and cerebellar tissues. In conclusion, abatement of AFB₁ -induced neurobehavioral abnormalities by GA involves anti-inflammatory, antioxidant, and antiapoptotic mechanisms in rats.

Activation of SOD-3 is involved in the antioxidant effect of a new class of β-aryl-chalcogenium azide compounds in Caenorhabditis elegans

Organic selenium, tellurium and sulfur compounds have been studied due to their pharmacological properties. For instance, the β-aryl-chalcogenium azide compounds have demonstrated antitumoral action in vitro. However, yet no pharmacological actions of this class of compounds were determined in vivo. Caenorhabditis elegans is a nematode that presents innumerable advantages in relation to mammalian models, such as having a small and transparent body, which allows the visualization of its internal anatomy, besides short life and low cost. Based on that, the aim of this work was to investigate the pharmacological and toxicological properties of β-aryl-chalcogenium azide compounds in C. elegans. As well, to evaluate the capacity of organochalcogenium compounds to repair oxidative damage induced by hydrogen peroxide and the possible mechanism of action of these compounds using CF1553 transgenic strain with superoxide dismutase (SOD-3) tagged with GFP. Our results showed that β-aryl-chalcogenium azide have low toxicity in wild-type worms and the pre-treatment protected against the damage induced by hydrogen peroxide at higher tested concentration. Associated with this, we observed that this protection is due in part to the increased expression of the antioxidant enzyme SOD-3. In conclusion, β-aryl-chalcogenium azide compounds caused low toxicity and induced stress-resistance by modulating SOD-3 expression in C. elegans.

Dietary glutamate and the brain: In the footprints of a Jekyll and Hyde molecule

Glutamate is a crucial neurotransmitter of the mammalian central nervous system, a molecular component of our diet, and a popular food-additive. However, for decades, concerns have been raised about the issue of glutamate's safety as a food additive; especially, with regards to its ability (or otherwise) to cross the blood-brain barrier, cause excitotoxicity, or lead to neuron death. Results of animal studies following glutamate administration via different routes suggest that an array of effects can be observed. While some of the changes appear deleterious, some are not fully-understood, and the impact of others might even be beneficial. These observations suggest that with regards to the mammalian brain, exogenous glutamate might exert a double-sided effect, and in essence be a two-faced molecule whose effects may be dependent on several factors. This review draws from the research experiences of the authors and other researchers regarding the effects of exogenous glutamate on the brain of rodents. We also highlight the possible implications of such effects on the brain, in health and disease. Finally, we deduce that beyond the culinary effects of exogenous glutamate, there is the possibility of a beneficial role in the understanding and management of brain disorders.

Role of 5-HT1A Receptor in the Anxiolytic-Relaxant Effects of Bergamot Essential Oil in Rodent

The essential oil obtained by the fresh fruit of Citrus bergamia Risso et Poiteau is used worldwide in aromatherapy to reduce pain, facilitate sleep induction, and/or minimize the effects of stress-induced anxiety. Preclinical pharmacological data demonstrate that bergamot essential oil (BEO) modulates specific neurotransmissions and shows an anxiolytic-relaxant effect not superimposable to that of the benzodiazepine diazepam, suggesting that neurotransmissions, other than GABAergic, could be involved. Several studies on essential oils indicate a role for serotonergic (5-HT) neurotransmission in anxiety. Interestingly, among serotonergic receptors, the 5-HT1A subtype seems to play a key role in the control of anxiety. Here, we report that modulation of the 5-HT1A receptor by selective agonist ((±)8-OH-DPAT) or antagonist (WAY-100635) may influence some of the anxiolytic-relaxant effects of BEO in Open Field and Elevated Plus Maze tests.

Minocycline alleviates NLRP3 inflammasome-dependent pyroptosis in monosodium glutamate-induced depressive rats

BACKGROUND

Inflammasome activation and followed by the release of proinflammatory cytokines play a pivotal role in the development and progression of depression. However, the involvement of gasdermin D (GSDMD)-mediated pyroptosis in inflammasome-associated depression has not been studied. The present study aimed to determine the involvement of pyroptosis in the development of depression.

METHODS

The rat depressive model was established by the administration of monosodium glutamate (MSG) in postnatal rats. Minocycline (an anti-inflammatory agent) and VX-765 (a specific inhibitor of caspase-1) were given as intervention treatments when rats were two-month-old. Rat depressive behaviors were evaluated by behavioral tests, including open field test, sucrose preference test, and forced swim test. Rat hippocampi were collected for western blotting and immunofluorescence examination.

RESULTS

MSG administration induced depressive-like behavior in rats. MSG upregulated protein presences of caspase-1, GSDMD, interleukin-1β (IL-1β), interleukin-18 (IL-18), NLR pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), high mobility group box 1 protein (HMGB1), and the receptor for advanced glycation end products (RAGE) in the hippocampus. Protein presences of HMGB1, NLRP3 and GSDMD were upregulated in Olig2+ oligodendrocytes in the hippocampus. The data suggest that both HMGB1/RAGE/NLRP3 signalings and GSDMD-dependent pyroptosis were activated. Both minocycline and VX-765 treatments improved depressive-like behaviors. Minocycline treatment significantly reduced both HMGB1/RAGE/NLRP3 inflammasome signalings and GSDMD-dependent pyroptosis. VX-765 downregulated GSDMD-dependent pyroptosis, but not HMGB1/RAGE signalings, indicating that GSDMD-dependent pyroptosis is a key player in the progress of depression.

CONCLUSION

In rats hippocampus, NLRP3 inflammasome activates GSDMD mediated-pyroptosis in the hippocampus of MSG-induced depressive rats.

Neurobehavioural and biochemical responses associated with exposure to binary waterborne mixtures of zinc and nickel in rats

Environmental and occupational exposure to metal mixtures due to various geogenic and anthropogenic activities poses a health threat to exposed organisms. The outcome of systemic interactions of metals is a topical area of research because it may cause either synergistic or antagonistic effect. The present study investigated the impact of co-exposure to environmentally relevant concentrations of waterborne nickel (75 and 150 μg NiCl ₂ L^-1) and zinc (100 and 200 μg ZnCl₂ L^-1) mixtures on neurobehavioural performance of rats. Locomotor, motor and exploratory activities were evaluated using video-tracking software during trial in a novel arena and thereafter, biochemical and histological analyses were performed using the cerebrum, cerebellum and liver. Results indicated that zinc significantly (p < 0.05) abated the nickel-induced locomotor and motor deficits as well as improved the exploratory activity of exposed rats as verified by track plots and heat map analyses. Moreover, zinc mitigated nickel-mediated decrease in acetylcholinesterase activity, elevation in biomarkers of liver damage, levels of reactive oxygen and nitrogen species as well as lipid peroxidation in the exposed rats when compared with control. Additionally, nickel mediated decrease in antioxidant enzyme activities as well as the increase in tumour necrosis factor alpha, interleukin-1 beta and caspase-3 activity were markedly abrogated in the cerebrum, cerebellum and liver of rats co-exposed to nickel and zinc. Histological and histomorphometrical analyses evinced that zinc abated nickel-mediated neurohepatic degeneration as well as quantitative reduction in the widest diameter of the Purkinje cells and the densities of viable granule cell layer of dentate gyrus, pyramidal neurones of cornu ammonis 3 and cortical neurons in the exposed rats. Taken together, zinc abrogated nickel-induced neurohepatic damage via suppression of oxido-inflammatory stress and caspase-3 activation in rats.

Preventive Effects of Escitalopram Against Anxiety-Like Depressive Behaviors in Monosodium Glutamate-Teated Rats Subjected to Partial Hepatectomy

The reasons for the relationship between depression and chronic liver disease (CLD) are complex and multifactorial. Further research is needed to decipher the etiology and establish an optimal management approach for depression in patients, including the potential role of non-pharmacological treatments. monosodium glutamate (MSG)-treated rats are more likely to develop anxiogenic- and depressive-like behaviors, which could be related to the dysfunction of serotonergic system. In this study, partial hepatectomy (PH) was performed in MSG-treated rats and the histopathological changes were observed in orbitofrontal cortex (OFC) and liver. The effect of escitalopram, a widely used antidepressant, on neural and liver injury in this model was also examined. The MSG + PH-treated rats displayed decreased distances traveled in total, in center arena, and in the left side of arena in inner open field test (OFT), as compared to saline, saline + PH, and MSG-treated animals. The present study established that PH aggravated anxiety-like depressive behaviors in MSG-treated rats, concordant with damaged Nissl bodies (and neurites), decreased IBA-1 and Sox-2 expression in OFC and neurotransmitter disorder. Escitalopram treatment could alleviate these pathological changes as well as reduce hepatic steatosis and lipid metabolism.

Oral Monosodium Glutamate Differentially Affects Open-Field Behaviours, Behavioural Despair and Place Preference in Male and Female Mice

Background:

Monosodium glutamate (MSG) is a flavour enhancer which induces behavioural changes in animals. However the influence of sex on the behavioural response to MSG has not been investigated.

Objective:

The sex-differential effects of MSG on open-field behaviours, anxiety-related behaviour, behavioural despair, place-preference, and plasma/brain glutamate levels in adult mice were assessed.

Methods:

Mice were assigned to three groups (1-3), based on the models used to assess behaviours. Animals in group 1 were for the elevated-plus maze and tail-suspension paradigms, group 2 for the open-field and forced-swim paradigms, while mice in group 3 were for observation in the conditioned place preference paradigm. Mice in all groups were further assigned into five subgroups (10 males and 10 females), and administered vehicle (distilled water at 10 ml/kg) or one of four doses of MSG (20, 40, 80 and 160 mg/kg) daily for 6 weeks, following which they were exposed to the behavioural paradigms. At the end of the behavioural tests, the animals were sacrificed, and blood was taken for estimation of glutamate levels. The brains were also homogenised for estimation of glutamate levels.

Results:

MSG was associated with a reduction in locomotion in males and females (except at 160 mg/kg, male), an anxiolytic response in females, an anxiogenic response in males, and decreased behavioural despair in both sexes (females more responsive). Postconditioning MSG-associated place-preference was significantly higher in females. Plasma/ brain glutamate was not significantly different between sexes.

Conclusion:

Repeated MSG administration alters a range of behaviours in a sex-dependent manner in mice.

Prospective association between ultra-processed food consumption and incident depressive symptoms in the French NutriNet-Santé cohort

BACKGROUND

Ultra-processed food (UPF) consumption has increased over the last decades in Westernized countries. Our objective was to investigate for the first time the association between the proportion of UPF (%UPF) in the diet and incident depressive symptoms in the NutriNet-Santé cohort.

METHODS

The sample included 20,380 women and 6350 men (aged 18-86 years) without depressive symptoms at the first Center for Epidemiologic Studies Depression Scale (CES-D) measurement, using validated cut-offs (CES-D score ≥ 17 for men and ≥ 23 for women). The proportion of UPF in the diet was computed for each subject using the NOVA classification applied to dietary intakes collected by repeated 24-h records (mean = 8; SD = 2.3). The association between UPF and depressive symptoms was evaluated using multivariable Cox proportional hazards models.

RESULTS

Over a mean follow-up of 5.4 years, 2221 incident cases of depressive symptoms were identified. After accounting for a wide range of potential confounders, an increased risk of depressive symptoms was observed with an increased %UPF in the diet. In the main model adjusted for sociodemographic characteristics, body mass index, and lifestyle factors, the estimated hazard ratio for a 10% increase in UPF was 1.21 (95% confidence interval = 1.15-1.27). Considering %UPF in food groups, the association was significant only for beverages and sauces or added fats.

CONCLUSION

Overall, UPF consumption was positively associated with the risk of incident depressive symptoms, suggesting that accounting for this non-nutritional aspect of the diet could be important for mental health promotion.

Dietary composition modulates impact of food-added monosodium glutamate on behaviour, metabolic status and cerebral cortical morphology in mice

Effects of food-added monosodium glutamate (MSG) on neurobehaviour, serum biochemical parameters, malondialdehyde (MDA) levels, and changes in cerebral cortex, liver and kidney morphology were assessed in mice fed standard diet (SD) or high-fat diet (HFD). Animals were assigned to 8 groups [SD control, HFD control, and six groups fed MSG plus SD or HFD at 0.1, 0.2 and 0.4 g/kg of feed]. Animals were fed for 8 weeks, behavioural tests were conducted, and blood was taken for estimation of biochemical parameters and MDA level. Whole brain was homogenised for neurochemical assays, while the cerebrum, liver and kidneys were processed for histology. In groups fed MSG/SD, there was a decrease in weight gain, increase in food-intake, an increase in locomotion, a decrease in rearing/grooming, and a decrease in anxiety-response. Also observed were derangements in biochemical parameters, increased MDA, and alteration of renal morphology. Compared to HFD, MSG/HFD groups had reduction in weight gain, food-intake, grooming and anxiety-response, an increase in locomotion, and improved memory. Protection against biochemical derangements and HFD-induced organ injuries were also observed. In conclusion, the findings suggest that possible interactions that may occur between dietary constituents and MSG are determinants of the effects of food-added MSG in mice.

Protective Effects of Liu Wei Di Huang Wan on the Liver, Orbitofrontal Cortex Nissl Bodies, and Neurites in MSG+PH-Induced Liver Regeneration Rat Model

Introduction. To examine the protective effects of Liu Wei Di Huang Wan formula (LWDH) on liver and orbitofrontal cortex (OFC) injuries in monosodium glutamate (MSG) and partial hepatectomy (PH) rat model. Methods. Neonatal Wistar rats were given MSG or saline on postnatal days 2, 4, 6, 8, and 10. The rats were caged into five groups and treated accordingly at six weeks old as follows: Saline group, Saline+PH group, MSG group, MSG+PH group, and LWDH group (MSG+PH+LWDH). The PH was performed during week 8 by excision of the left and median hepatic lobes (occupying about 68% of whole liver).On day 8 after the PH, the rats were subjected to an inner OFT before being sacrificed. The liver and OFC were stained using H&E, ORO, or Nissl staining. The expression of neurotrophic factors (β-NGF, BDNF) was examined in the OFC lysates by ELISA. Serum levels of cytokines (IL-1β, VEGF) were examined using the Bio-Plex suspension array. Results. LWDH increased the total distance traveled by the animals (p<0.05), and LWDH improved the integrity of the Nissl bodies in the OFC (mean area of the Nissl bodies, p<0.01; mean diameter, p<0.05; mean density, p<0.05; and IOD, p<0.01). There were less white area in the liver (p>0.05) and decreased hepatic steatosis (p<0.01) in LWDH group. LWDH administration decreased the expression of serum levels of IL-1β (p>0.05), while it increased VEGF (p>0.05) expression. LWDH administration increased the expression of BDNF (p>0.05) and β-NGF (p>0.05) in the OFC, all as compared to the MSG+PH group. Conclusion. LWDH partly protected the animals from depressive-like behaviors in the MSG+PH-induced liver regeneration neonatal rat model. LWDH alleviated hepatic injury and steatosis and, furthermore, protected the Nissl body integrity and the growth of neurites.

Dietary Neurotransmitters: A Narrative Review on Current Knowledge

Foods are natural sources of substances that may exert crucial effects on the nervous system in humans. Some of these substances are the neurotransmitters (NTs) acetylcholine (ACh), the modified amino acids glutamate and γ-aminobutyric acid (GABA), and the biogenic amines dopamine, serotonin (5-HT), and histamine. In neuropsychiatry, progressive integration of dietary approaches in clinical routine made it necessary to discern the more about some of these dietary NTs. Relevant books and literature from PubMed and Scopus databases were searched for data on food sources of Ach, glutamate, GABA, dopamine, 5-HT, and histamine. Different animal foods, fruits, edible plants, roots, and botanicals were reported to contain NTs. These substances can either be naturally present, as part of essential metabolic processes and ecological interactions, or derive from controlled/uncontrolled food technology processes. Ripening time, methods of preservation and cooking, and microbial activity further contributes to NTs. Moreover, gut microbiota are considerable sources of NTs. However, the significance of dietary NTs intake needs to be further investigated as there are no significant data on their bioavailability, neuronal/non neuronal effects, or clinical implications. Evidence-based interventions studies should be encouraged.

An Interesting Tour of New Research Results on Umami and Umami Compounds

Knowledge about the fifth basic taste, the umami taste, has been investigated by many scientists in the last years and continues to gain importance. Therefore, a lot of scientific studies were conducted to explore several effects influencing the mechanism of umami, which is elicited and enhanced by defined concentrations of MSG (monosodium glutamate) and umami compounds. This paper covers the most relevant scientific literature regarding umami, its use as a flavor enhancer, and the latest umami compounds, which have been released in the last ten years. The main goal of this overview was to summarize the most important results which were related to umami as one of the five basic tastes, the umami taste receptor, the essential role of umami in a great number of physiological mechanisms, and the MSG symptom complex. Furthermore, the function of umami in the interaction of taste, aftertaste and olfactory pathways has been discussed.

Diphenyl diselenide elicits antidepressant-like activity in rats exposed to monosodium glutamate: A contribution of serotonin uptake and Na(+), K(+)-ATPase activity

Depression is a disorder with symptoms manifested at the psychological, behavioral and physiological levels. Monosodium glutamate (MSG) is the most widely used additive in the food industry; however, some adverse effects induced by this additive have been demonstrated in experimental animals and humans, including functional and behavioral alterations. The aim of this study was to investigate the possible antidepressant-like effect of diphenyl diselenide (PhSe)2, an organoselenium compound with pharmacological properties already documented, in the depressive-like behavior induced by MSG in rats. Male and female newborn Wistar rats were divided in control and MSG groups, which received, respectively, a daily subcutaneous injection of saline (0.9%) or MSG (4g/kg/day) from the 1st to 5th postnatal day. At 60th day of life, animals received (PhSe)2 (10mg/kg, intragastrically) 25min before spontaneous locomotor and forced swimming tests (FST). The cerebral cortices of rats were removed to determine [(3)H] serotonin (5-HT) uptake and Na(+), K(+)-ATPase activity. A single administration of (PhSe)2 was effective against locomotor hyperactivity caused by MSG in rats. (PhSe)2 treatment protected against the increase in the immobility time and a decrease in the latency for the first episode of immobility in the FST induced by MSG. Furthermore, (PhSe)2 reduced the [(3)H] 5-HT uptake and restored Na(+), K(+)-ATPase activity altered by MSG. In the present study a single administration of (PhSe)2 elicited an antidepressant-like effect and decrease the synaptosomal [(3)H] 5-HT uptake and an increase in the Na(+), K(+)-ATPase activity in MSG-treated rats.

Monosodium glutamate in chicken and beef stock cubes using high-performance liquid chromatography

In this survey monosodium glutamate (MSG) levels in chicken and beef stock cube samples were determined. A total number of 122 stock cube samples (from brands A, B, C, D) were collected from local markets in Ankara, Turkey. High-performance liquid chromatography with diode array detection (HPLC-DAD) was used for quantitative MSG determination. Mean MSG levels (±SE) in samples of A, B, C and D brands were 14.6 ± 0.2 g kg⁻¹, 11.9 ± 0.3 g kg⁻¹, 9.7 ± 0.1 g kg⁻¹ and 7.2 ± 0.1 g kg⁻¹, respectively. Differences between mean levels of brands were significant. Also, mean levels of chicken stock cube samples were lower than in beef stock cubes. Maximum limits for MSG in stock cubes are not specified in the Turkish Food Codex (TFC). Generally the limit for MSG in foods (except some foods) is established as 10 g kg⁻¹ (individually or in combination).

Nutritional psychiatry research: an emerging discipline and its intersection with global urbanization, environmental challenges and the evolutionary mismatch

In 21st-century public health, rapid urbanization and mental health disorders are a growing global concern. The relationship between diet, brain function and the risk of mental disorders has been the subject of intense research in recent years. In this review, we examine some of the potential socioeconomic and environmental challenges detracting from the traditional dietary patterns that might otherwise support positive mental health. In the context of urban expansion, climate change, cultural and technological changes and the global industrialization and ultraprocessing of food, findings related to nutrition and mental health are connected to some of the most pressing issues of our time. The research is also of relevance to matters of biophysiological anthropology. We explore some aspects of a potential evolutionary mismatch between our ancestral past (Paleolithic, Neolithic) and the contemporary nutritional environment. Changes related to dietary acid load, advanced glycation end products and microbiota (via dietary choices and cooking practices) may be of relevance to depression, anxiety and other mental disorders. In particular, the results of emerging studies demonstrate the importance of prenatal and early childhood dietary practices within the developmental origins of health and disease concept. There is still much work to be done before these population studies and their mirrored advances in bench research can provide translation to clinical medicine and public health policy. However, the clear message is that in the midst of a looming global epidemic, we ignore nutrition at our peril.