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

Abstract

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 .

Effects of the food additive monosodium glutamate on cisplatin‐induced gastrointestinal dysmotility and peripheral neuropathy in the rat

“…Our previous studies with oxaliplatin demonstrate that platinum‐based anti‐cancer agents induce oxidative stress leading to neuronal damage and death underlying post‐treatment dysfunctions 7 . MSG‐induced neuroprotection may be due to improvements in the endogenous antioxidant profile, with reduction of lipid peroxidation (malondialdehyde, MDA) and in glutation (GSH) levels 56 , and probably to an indirect effect on microtubules after interaction with a receptor found only on neural cells 55 . Further studies are warranted to determine the pathways, receptors and mediators involved in the neuroprotective effects of MSG, including the possibility that it might prevent platinum accumulation (another mechanism underlying long‐term peripheral sensory neuropathy 57,58 ).…”

The effect of cordycepin on brain oxidative stress and protein expression in streptozotocin-induced diabetic mice

“…Several studies have reported that impaired glutamate signaling is associated with cognitive dysfunction [ 56 ]. Additionally, chronic supplementation of glutamate at adequate amounts can improve memory performance, including spatial, recognition, and associative memory processes [ 64 ]. Interestingly, in the present study, ULK1, a serine/threonine-protein kinase, was the only protein expressed uniquely in diabetic mice treated with cordycepin ( Table 2 ).…”

Comprehensive profiling of bioactive compounds in germinated black soybeans via UHPLC-ESI-QTOF-MS/MS and their anti-Alzheimer’s activity

“…GABA is an essential amino acid that serves as an inhibitory neurotransmitter for brain and plays role in information processing, neuronal development and cognition. Studies are suggesting that aggregation of Aβ peptides in the hippocampus interfere with GABA inhibitory interneuron function and promote memory impairment [5]. Further, defects in the cholinergic system can reduce the ACh levels in the brain due to the loss of cholinergic neurons and neurotransfomation.…”