Monosodium glutamate monohydrate 4.276g/100ml / Monosodium aspartate monohydrate 3.924g/100ml solution for infusion bottles

BACKGROUND AND OBJECTIVE: NMDA receptors, predominantly located in the central nervous system and known for their roles in synaptic plasticity and central sensitisation of pain and itch, are also expressed in peripheral sensory neurons. Emerging evidence suggests that peripheral NMDA receptors contribute to pathological pain and potentially itch, identifying them as promising therapeutic targets. The aim of this review is to explore the role of peripheral NMDA receptors in pain and itch and to summarise the effectiveness of topical NMDA antagonists in managing these sensations. DATABASES AND DATA TREATMENT: This review was conducted through a systematic search of the PubMed database using MeSH terms and keywords related to 'peripheral NMDA receptors', 'pain', 'itch' and 'topical ketamine'. Additional references were included based on expert knowledge and reference tracking. Only English-language articles were considered. RESULTS: Animal studies demonstrate that peripheral NMDA receptors are involved in inflammatory and certain neuropathic pain models, with antagonists showing analgesic effects. Limited studies also suggest their role in non-histaminergic itch through glutamate signalling. In humans, topical ketamine has shown mixed results for pain relief, and preliminary clinical reports suggest potential antipruritic effects. However, controlled clinical trials, particularly for itch, are lacking. CONCLUSION: Peripheral NMDA receptors are involved in the transmission and sensitisation of both pain and itch, especially under pathological conditions. While topical ketamine may offer therapeutic benefits, particularly for non-histaminergic itch and neuropathic pain, further clinical research is necessary to confirm its efficacy, safety and optimal use. SIGNIFICANCE STATEMENT: This review highlights the underexplored role of peripheral NMDA receptors in itch, especially non-histaminergic pathways, and synthesises emerging evidence for their therapeutic potential. By comparing pain and itch mechanisms, it suggests that topical ketamine could serve as novel treatments for refractory itch and localised pain, warranting further clinical investigation.

Abstract licence: CC BY-NC-ND

Monosodium glutamate (MSG) is the sodium salt of glutamic acid (GLA), used as a flavour enhancer. MSG is considered a controversial substance. It is incriminated in disturbing the antioxidant system, but also has beneficial effects, as GLA metabolism plays a crucial role in homeostasis. This study highlights which positive or negative aspects of MSG sub-chronic consumption are better reflected in subjects potentially affected by advanced age. Daily doses of MSG were administered to four groups of two-year-old Wistar rats for 90 days: (I) 185 mg/kg bw, (II) 1500 mg/kg bw, (III) 3000 mg/kg bw and (IV) 6000 mg/kg bw, compared to a MSG non-consumer group. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, direct and total bilirubin, total cholesterol, triglycerides, creatinine and urea levels were analysed; stomach, liver and kidney samples were subjected to histopathological analysis. Although, in most cases, there were no statistical differences, interesting aspects of the dose-effect relationship were observed. After MSG sub-chronic consumption, the positive aspects of GLA seem to be reflected better than the negative ones. The hormesis effect, with low-level reactive oxygen species' protective effects and GLA metabolism, may represent the hypothesis of a potential defence mechanism triggered by MSG sub-chronic consumption in ageing rats.

Abstract licence: CC BY

Umami is a fundamental taste, associated with the molecules of monosodium glutamate and other amino acids and nucleotides present in many fermented foods and beverages, including wine. Umami also plays the role of flavor enhancer and prolongs the aftertaste. In this research, monosodium glutamate and aspartate, responsible for the umami taste, were quantified in Italian still and sparkling white wines aged through contact with yeasts. The wines were studied from a sensory point of view to quantify the perception of umami and relate it to other sensory parameters. The results show that monosodium glutamate and aspartate are present in the wines studied. However, sensory analysis shows that there is no clear relationship between the umami taste and the concentration of the two amino acids, but their presence plays a fundamental role in enhancing other gustatory and olfactory perceptions, making them even more persistent.

Abstract licence: CC BY

BACKGROUND: Monosodium glutamate (MSG) is a flavor enhancer used in food industries. MSG is well documented to induce neurotoxicity. Curcumin (CUR) reportedly possesses beneficial effects against various neurotoxic insults. Hence, this present study has been designed to evaluate the neuroprotective effect of curcumin on MSG-induced neurotoxicity in rats. METHODS: Thirty-two male Wister rats were divided into four groups (n=8): Control group, MSG group, CUR group and MSG + CUR group. CUR (Curcumin 150 mg/kg, orally) was given day after day for four weeks along with MSG (4 mg/kg, orally). After 4 weeks, rats were sacrificed and brain hippocampus was isolated immediately on ice. Inflammatory marker TNFα and acetylcholinesterase (AChE) activity (marker for cholinergic function) were estimated. Gene expressions of metabotropic glutamate receptor 5 (mGluR5) and N-methyl-D-aspartate receptor 2B (NMDA2B) along with glutamate concentration were assessed. RESULTS: Treatment with CUR significantly attenuated AChE activity and TNFα in MSG-treated animals. The anti-inflammatory properties of CUR may be responsible for this observed neuroprotective action. A possible role of CUR to attenuate both glutamate level and gene expression of NMDA2B and mGLUR5 in brain hippocampus was established when compared to MSG group. CONCLUSION: We concluded that CUR as flavor enhancer protects against MSG-induced neurotoxicity in rats.

Abstract licence: CC BY-NC-ND

Monosodium glutamate (MSG) is commonly used as a culinary flavouring, although research suggest that it is toxic to people and laboratory animals, especially in high dosages. The study goal is to determine the impact of Aframomum sceptrum (ataiko) treatment on hepatic induced toxicity by MSG. Thirty-six albino rats (male) with weight of 120 to 210 g were used for the study. The rats were separated into 6 groups in which each group contains six rats. Group 1: normal control. Group 2: MSG only. Group 3 and 4 were given MSG and then treated with 250 and 350 mg/kg b.wt of A. sceptrum extract respectively. Group 5 and 6 were administered only 250 and 350 mg/kg b.wt of A. sceptrum extract, respectively. The MSG groups were given intra-peritoneal injection of MSG solution at single dose of 4253 mg/kg b.wt. A. sceptrum extract was administered three times a week for four weeks beginning two days after the MSG induction. Liver function markers such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and oxidative stress markers such as reduced glutathione (GSH) and malondialdehyde (MDA) were determined in serum and liver. Also, glucose was determined in the serum. The results showed that there were significant (p < 0.05) increased in glucose, AST, ALT and MDA in serum and liver, and decreased in GSH level in the liver of rats given MSG only when compared with normal control. However, A. sceptrum administration significantly (p < 0.05) decreased glucose, AST, ALT and MDA in the serum and liver, and increased GSH level in the liver when compared with MSG only. In conclusion, aqueous extract of A. sceptrum may have beneficial effect in MSG induced toxicity in rats by improving GSH level as well as liver function markers in a dose dependent manner.

Abstract licence: CC BY-NC

The exact mechanisms that trigger the activation of the trigeminovascular system in migraine remain unclear. The involvement of calcitonin gene-related peptide (CGRP) in migraine is well-documented, and treatments aimed at blocking CGRP activity have proven successful in reducing migraine attacks for some patients. However, around one third of individuals do not respond to these therapies, which are also limited by factors like cost, side effects, and contraindications. There is growing evidence suggesting that glutamate, an excitatory neurotransmitter, plays a crucial role in the onset and maintenance of migraine pain, partially by enhancing CGRP release. Increased glutamate levels have been linked to both peripheral and central sensitization, potentially contributing to the development and persistence of chronic migraine. The relationship between CGRP and glutamate is complex, with glutamate possibly acting as an upstream trigger for CGRP release. This review examines the interplay between CGRP and glutamate, and their involvement in both peripheral and central sensitization. It also explores the therapeutic potential of targeting either glutamate or CGRP, aiming to address both peripheral and central migraine mechanisms. Finally, the role of triggers in migraine initiation at the peripheral level is discussed, offering insights into potential preventive strategies.

Abstract licence: CC BY-NC-ND

Monosodium glutamate (MSG) is commonly used as a flavor-enhancing agent in foods, and studies have demonstrated its toxic effects in animal models. Black garlic is known for its antioxidant and anti-inflammatory properties; however, there is a lack of studies on the potential hepatoprotective effect of black garlic ethanol extract (BGE) against MSG-induced hepatotoxicity in rats. The aim of this study was to investigate the hepatoprotective effects of ethanol extract of black garlic against MSG-induced liver damage in animal model. Twenty-five male Wistar rats were randomly assigned to five groups (n=5): negative control, MSG only, and MSG with three different doses of BGE. The MSG only and MSG with BGE groups were orally administered with 8 mg/kg MSG daily. After MSG treatment, the MSG with BGE groups received BGE orally at daily doses of 200, 400, or 600 mg/kg body weight for 16 consecutive days. Subsequently, the levels of serum liver enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), interferon-gamma (IFN-γ), and cyclooxygenase-2 (COX-2) were measured. Our data indicated that the group treated with 200 mg/kg BGE had significant lower levels of AST and ALT significantly compared to the MSG-only group. The MSG-treated group had higher levels of the inflammatory markers COX-2 and IFN-γ, which were lowered by administration of 200 mg/kg BGE. In contrast, higher doses of BGE led to greater levels of COX-2 and IFN-γ compared to those in the MSG-only group. This study suggested that BGE might have hepatoprotective effects at low dose, potentially mitigating MSG-induced liver damage. However, the higher dose of black garlic extract did not alleviate inflammation, as shown by the higher levels of COX-2 and IFN-γ.

Abstract licence: CC BY-NC