Metabolism of Dietary Glutamate in Adults

Cynober, Luc

doi:10.1159/000494776

Cited by 45 publications

(21 citation statements)

References 55 publications

(98 reference statements)

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“…Along with these redox enzymes, certain endogenous antioxidants primarily GSH and proteins also provide defence against ROS via maintaining redox homoeostasis 48 . Studies have reported that ingested glutamate is transported to enterocytes via specific Na-dependent transporters and major amount (75-80%) is metabolized in the intestine by transamination, some amount (5-10%) enters into blood circulation, while 10-15% is converted to Glutamine and other bioactive molecules of sensory and signaling pathways 49,50 . Along with this free glutamate is also reported to have an important role in protein stability as it provides a negative charge 50 .…”

Section: Discussionmentioning

confidence: 99%

Free l-glutamate-induced modulation in oxidative and neurochemical profile contributes to enhancement in locomotor and memory performance in male rats

Tabassum

Ahmad

Madiha

et al. 2020

Sci Rep

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Glutamate (Glu), the key excitatory neurotransmitter in the central nervous system, is considered essential for brain functioning and has a vital role in learning and memory formation. earlier it was considered as a harmful agent but later found to be useful for many body functions. However, studies regarding the effects of free l-Glu administration on CNS function are limited. Therefore, current experiment is aimed to monitor the neurobiological effects of free l-Glu in male rats. l-Glu was orally administered to rats for 5-weeks and changes in behavioral performance were monitored. Thereafter, brain and hippocampus were collected for oxidative and neurochemical analysis. Results showed that chronic supplementation of free l-Glu enhanced locomotor performance and cognitive function of animals which may be attributed to the improved antioxidant status and cholinergic, monoaminergic and glutamatergic neurotransmission in brain and hippocampus. current results showed that chronic supplementation of l-Glu affects the animal behaviour and brain functioning via improving the neurochemical and redox system of brain. free l-Glu could be a useful therapeutic agent to combat neurological disturbances however this requires further targeted studies. Central nervous system (CNS) modulates behaviour and brain functioning with the help of multiple neurotransmitters. One of the important neurotransmitters is Glutamate (Glu) 1 which is a nonessential amino acid (AA) present abundantly in the body 2. It is involved in a variety of body functions either directly or by converting into other products 3. Evidence shows the importance of Glu in facilitating protein synthesis 4 , intestinal nutrition, cell signalling, gene expression modulation, immune responses 5 , regulating blood glucose level, removing excess ammonia 6 , disposal of excess or waste nitrogen 7 as well as in intermediary metabolism 2 as an important energy fuel 5. Other than this, it is also a precursor of various biologically active components like glutathione (GSH), GABA, purine and pyrimidine nucleotides, polyamines, poly-glutamated folate cofactors or certain AAs like glutamine, alanine, aspartate, proline, arginine, citrulline 2-5,8. Glu is present in various foods either as naturally occurring free Glu (vegetable, seafood, milk, meat, cheese) or as a by-product of hydrolysed protein (used in seasoning) or as a salt; MSG (monosodium glutamate), a food additive or flavouring agent in canned foods, dry mixes, sauces, and soups 9 .

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Section: Discussionmentioning

confidence: 99%

Free l-glutamate-induced modulation in oxidative and neurochemical profile contributes to enhancement in locomotor and memory performance in male rats

Tabassum

Ahmad

Madiha

et al. 2020

Sci Rep

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“…Glutamate produced by the formimino transferase reaction may be used for synthesis of glutamine, may become deaminated to α-ketoglutarate in a glutamate dehydrogenase reaction, and/or may be released to the blood [49]. Transamination to alanine is unlikely to occur due to excess alanine concentration obtained from extrahepatic tissues.…”

Section: His Catabolism In the Livermentioning

confidence: 99%

Histidine in Health and Disease: Metabolism, Physiological Importance, and Use as a Supplement

2020

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L-histidine (HIS) is an essential amino acid with unique roles in proton buffering, metal ion chelation, scavenging of reactive oxygen and nitrogen species, erythropoiesis, and the histaminergic system. Several HIS-rich proteins (e.g., haemoproteins, HIS-rich glycoproteins, histatins, HIS-rich calcium-binding protein, and filaggrin), HIS-containing dipeptides (particularly carnosine), and methyl- and sulphur-containing derivatives of HIS (3-methylhistidine, 1-methylhistidine, and ergothioneine) have specific functions. The unique chemical properties and physiological functions are the basis of the theoretical rationale to suggest HIS supplementation in a wide range of conditions. Several decades of experience have confirmed the effectiveness of HIS as a component of solutions used for organ preservation and myocardial protection in cardiac surgery. Further studies are needed to elucidate the effects of HIS supplementation on neurological disorders, atopic dermatitis, metabolic syndrome, diabetes, uraemic anaemia, ulcers, inflammatory bowel diseases, malignancies, and muscle performance during strenuous exercise. Signs of toxicity, mutagenic activity, and allergic reactions or peptic ulcers have not been reported, although HIS is a histamine precursor. Of concern should be findings of hepatic enlargement and increases in ammonia and glutamine and of decrease in branched-chain amino acids (valine, leucine, and isoleucine) in blood plasma indicating that HIS supplementation is inappropriate in patients with liver disease.

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“…This build-up of glutamate is not due to reduced conversion to GABA as we detected no corresponding difference in GABA levels ( 56 ). No increase in glutamate in the GF brain was detected in these GF mice with high intestinal glutamate levels, but glutamate is primarily metabolised in the splanchnic area and little enters into circulation from the gastrointestinal tract, instead exerting its significant localised effects on the gut including through stimulation of the vagus nerve ( 57 , 58 ).…”

Section: Discussionmentioning

confidence: 99%

Mapping the influence of the gut microbiota on small molecules in the brain through mass spectrometry imaging

Wall

Hulme

Meikle

et al. 2020

Preprint

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27Background: The gut microbiota is known to influence virtually all facets of human health. 28Recent work has highlighted a potential role for the gut microbiota in neurological health 29 through the microbiome-gut-brain axis. Microbes can influence the brain both directly and 30 indirectly; through neurotransmitter production, induction of host immunomodulators, or 31 through the release or induction of other microbial or host molecules. 32Methods: Here we used mass spectrometry imaging (MSI), a label-free imaging tool, to map 33 the molecular changes that occur in the murine gut and brain in germ-free, antibiotic-treated 34 and control mice. 35Results: We determined the spatial distribution and relative quantification of 36 neurotransmitters and their precursors across brain and gut sections in response to the 37 microbiome. Using untargeted MSI of small molecules, we detected a significant change in 38 the levels of four identified metabolites in the brains of germ-free animals compared to 39 controls; vitamin B5, 3-hydroxy-3-methylglutaric acid, 3-methyl-4- 40(trimethylammonio)butanoate and 4-(trimethylammonio)pentanoate. However, antibiotic 41 treatment induced no significant changes in these metabolites in the brain after one week of 42 treatment. 43Conclusions: This work exemplifies the utility of MSI as a tool in determining the spatial 44 distribution and quantification of bacterial and host metabolites in the gut and brain whilst also 45 offering the potential for discovery of novel mediators of microbiome-gut-brain axis 46 communication.47 48 49 50 Background 51Deciphering the complex bi-directional communication across the microbiome gut brain 52 (MGB) axis remains a challenging prospect. The composition and stability of the gut 53 microbiome is now proposed to be a significant contributor to human health with changes in 54 its composition suggested as a contributing factor in a number of neurological conditions. 55Diverse human neurological disorders, ranging from autism spectrum disorders (ASDs) and 56 attention-deficit/hyperactivity disorder (ADHD) to Alzheimer's and Parkinson's disease, have 57 linked gastrointestinal abnormalities or changes in the gut microbiome (1-6). Similarly, 58 altered levels of certain bacterial species in the gut have been linked with depression (7, 8). 59Despite the deficiencies of germ free (GF) animal models, their use for investigating links 60 between the gut microbiota and the brain have proved informative and are helping to uncover 61 the influence of bacteria on neurotransmitter levels alongside other bacterial and host 62 metabolites. Their neuro-developmental abnormalities including increased blood-brain-barrier 63 (BBB) permeability, alterations in abundance and maturity of microglia cells, and reduced 64 myelination (9-11) have been well documented but their use, alongside antibiotic treated 65 (ABX) mice, have provided further evidence that supports the importance of a stable and 66 healthy gut microbiota in maintaining normal cognitive function and developm...

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Metabolism of Dietary Glutamate in Adults

Cited by 45 publications

References 55 publications

Free l-glutamate-induced modulation in oxidative and neurochemical profile contributes to enhancement in locomotor and memory performance in male rats

Free l-glutamate-induced modulation in oxidative and neurochemical profile contributes to enhancement in locomotor and memory performance in male rats

Histidine in Health and Disease: Metabolism, Physiological Importance, and Use as a Supplement

Mapping the influence of the gut microbiota on small molecules in the brain through mass spectrometry imaging

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