Endogenous Dipeptide Research Articles

Carnosine modulates the Sp1-Slc31a1/Ctr1 copper-sensing system and influences copper homeostasis in murine CNS-derived cells.

Carnosine (CAR) is an endogenous dipeptide physiologically present in excitable tissues, such as central nervous system (CNS) and muscle. CAR is acknowledged as a substrate involved in many homeostatic pathways and mechanisms and, due to its biochemical properties, as a molecule intertwined with the homeostasis of heavy metals such as copper (Cu). In CNS, Cu excess and dysregulation imply oxidative stress, free-radical production, and functional impairment leading to neurodegeneration. Here, we report that CAR intercepts the regulatory routes of Cu homeostasis in nervous cells and tissues. Specifically, in a murine neuron-derived cell model, i.e., the B104 neuroblastoma cells, extracellular CAR exposure up to 24 h influenced intracellular Cu entry and affected (downregulated) the key Cu-sensing system, consisting of the gene coding for the Slc31a1 transmembrane Cu importer (alias Ctr1), and the gene coding for the Cu-responsive transcription factor Sp1 ( Sp1). Also, CAR exposure upregulated CAR biosynthesis ( Carns1), extracellular degradation ( Cndp1), and transport ( Slc15a4, alias Pht1) genes and elicited CAR intracellular accumulation, contributing to the outline of functional association between CAR and Cu within the cell. Interestingly, the same gene modulation scheme acting in vitro operates in vivo in brains of mice undergoing dietary administration of CAR in drinking water for 2 wk. Overall, our findings describe for the first time a regulatory interaction between CAR and Cu pathways in CNS and indicate CAR as a novel active molecule within the network of ligands and chaperones that physiologically regulate Cu homeostasis.

Carnosine as an effective neuroprotector in brain pathology and potential neuromodulator in normal conditions.

Carnosine (b-alanyl-L-histidine) is an endogenous dipeptide widely distributed in excitable tissues, such as muscle and neural tissues-though in minor concentrations in the latter. Multiple benefits have been attributed to carnosine: direct and indirect antioxidant effect, antiglycating, metal-chelating, chaperone and pH-buffering activity. Thus, carnosine turns out to be a multipotent protector against oxidative damage. However, the role of carnosine in the brain remains unclear. The key aspects concerning carnosine in the brain reviewed are as follows: its concentration and bioavailability, mechanisms of action in neuronal and glial cells, beneficial effects in human studies. Recent literature data and the results of our own research are summarized here. This review covers studies of carnosine effects on both in vitro and in vivo models of cerebral damage, such as neurodegenerative disorders and ischemic injuries and the data on its physiological actions on neuronal signaling and cerebral functions. Besides its antioxidant and homeostatic properties, new potential roles of carnosine in the brain are discussed.

Responsiveness of Carnosine Homeostasis Genes in the Pancreas and Brain of Streptozotocin-Treated Mice Exposed to Dietary Carnosine.

In excitable tissues, the endogenous dipeptide carnosine (CAR, β-Ala-l-His) sustains homeostatic responses to various challenges. By eliciting hypoglycemic effects via actions on the autonomic nervous system and protection of pancreatic beta-cells, CAR is also relevant in diabetes. We investigated the expression of genes involved in CAR biosynthesis, degradation, and membrane transport pathways, in the pancreas and brains of mice treated with streptozotocin (STZ) and then exposed to dietary CAR. We induced hyperglycemia by STZ intraperitoneal injections; then, STZ-treated mice received drinking water with or without CAR for two weeks. We report that CAR administration elicits beneficial effects on blood glucose levels and weight loss in STZ-treated mice and, remarkably, on the insulin gene products in the pancreas, preserving gene expression from STZ challenge. Also, we describe mRNA downregulation of the Slc15a2/Pept2 (dipeptide transporter) and Cndp2 (intracellular dipeptidase) genes in the pancreas of hyperglycemic mice, and dysregulation of Carns1 (CAR synthase), Pept2 and Cndp2 in brains; interestingly, dietary CAR elicits counteracting effects. These expression patterns associate with variations of CAR content in tissues of mice. Overall, our report suggests a direct role of CAR in the diabetes-affected pancreas and in the diabetes-targeted CNS, proposing (dys)regulation of CAR’s homeostasis as a marker condition.

PO-148 Suppression of carnosine on adhesion and extravasation in human colorectal cells

Introduction Colorectal cancer is the third most commonly diagnosed cancer in the word. Carnosine is an endogenous dipeptide found in muscle and brain tissues. The aims of this study are to investigate the regulation of carnosine on adhesion and extravasation of metastasis in human colorectal cancer. Material and methods The human colorectal cancer cells (HCT-116) and human umbilical vein cell line (EA. hy926) cultured were as experimental models. Those adhesive and extravasate abilities and regulate molecular expression were analysed in this study. Results and discussions In adhesion ability assay results shown carnosine were significantly decreased HCT-116 cells adhesion to endothelial cells (EA. hy926 cells). From adhesion-regulating proteins expression analysis result show that carnosine was decreased the levels of integrin in HCT-116 cells and ICAM-1 and E-selectin in EA hy926 cells after 24 hour incubation (p Conclusion The results indicate that carnosine can inhibit the adhesion and extravasation through suppressing of carnosine on NF-κB transcript activation and its regulator adhesion and extravasation related molecular expression in HCT-116 cells and EA hy926 cells.

Synthesis and Characterization of a Series of Orthogonally Protected l-Carnosine Derivatives

l-Carnosine (β-alanyl-l-histidine) is an endogenous dipeptide that has been recognized for its broad spectrum of beneficial biological activities. However, the therapeutic utility of molecule has been hampered by its instability in human plasma (half-life in human serum < 5 min) due to the presence of carnosinase enzyme that catalyzes its hydrolysis into the respective individual amino acids. While a large number of carnosine derivatives have been synthesized to optimize its overall pharmacokinetic profile, reports that provide molecular evidence as to how the dipeptide interacts with its biological target are scarce. Therefore, many questions are yet to be answered concerning the pharmacophoric regions in carnosine and its significance to the molecule’s diverse biological activities. In this study, we set out to construct a small library of carnosine analogues that can be used in assessing the influence of the various functional groups of the dipeptide on its important biological properties. Orthogonal protection/deprotection of selected functional groups led to the exposure of amino group at the N-terminus, the carboxyl group at the C-terminus, and the imidazole ring of histidine. To examine the significance of the imidazole group in preventing the aggregation of the β-amyloid plaques, histidine was replaced by phenylalanine and a series of β-Ala-Phe analogues was generated. To study the influence of the length of the carbon chain in β-Ala on the β-amyloid aggregation, a series of Gly-His analogues was synthesized. A series of Gly-Phe was also constructed and will be used as negative control in future β-amyloid plaque assembly experiments. The synthesized carnosine derivatives were characterized by NMR (proton, carbon, and 1H–1H COSY), and mass spectroscopy.

Zinc, Carnosine, and Neurodegenerative Diseases.

Zinc (Zn) is abundantly present in the brain, and accumulates in the synaptic vesicles. Synaptic Zn is released with neuronal excitation, and plays essential roles in learning and memory. Increasing evidence suggests that the disruption of Zn homeostasis is involved in various neurodegenerative diseases including Alzheimer’s disease, a vascular type of dementia, and prion diseases. Our and other numerous studies suggest that carnosine (β-alanyl histidine) is protective against these neurodegenerative diseases. Carnosine is an endogenous dipeptide abundantly present in the skeletal muscles and in the brain, and has numerous beneficial effects such as antioxidant, metal chelating, anti-crosslinking, and anti-glycation activities. The complex of carnosine and Zn, termed polaprezinc, is widely used for Zn supplementation therapy and for the treatment of ulcers. Here, we review the link between Zn and these neurodegenerative diseases, and focus on the neuroprotective effects of carnosine. We also discuss the carnosine level in various foodstuffs and beneficial effects of dietary supplementation of carnosine.

ID: 1029 Effects of carnosine on regulation of migration and invasion in human colorectal cancer cells

Colorectal cancer is the third most commonly diagnosed cancer in the word. Carnosine is an endogenous dipeptide found in vertebrate skeletal muscles. It is known to have anti-fatigue, antioxidative, antihypertensive, antidiabetic, and cancer inhibiting effects. However, little research has been done regarding its influence on the metastasis of colon cancer. This study cultivated HCT-116 human colon cancer cells as a test model in order to investigate the impact of carnosine on the migration and invasion of human colon cancer cells. The results showed that 48-hour treatments of HCT-116 cells with 0.5, 1, or 5 mM carnosine each significantly inhibited the migration ability of the cells (P &lt; 0.05). The 48-hour treatments with 0.5, 1, or 5 mM carnosine were also found to significantly reduce MMP-9 activity (P &lt; 0.05), but not MMP-2 expression. Furthermore, when HCT-116 cells treated with 1 or 5 mM carnosine, invasion ability are significantly decreased and significantly increased E-cadherin expression (P &lt; 0.05). On the other hand, the protein of TIMP-1, an inhibitor of MMP-9, is signification increased after 1 or 5 mM carnosine treatment (P&lt;0.05). In addition, the u-PA protein level are significantly decreased after carnosine treatment.&#x0D; The results indicate that carnosine can regulate the migration and invasion by regulating MMPs and its regulator molecular expression in HCT-116 cells.

Pharmacological Potential of the Endogenous Dipeptide Kyotorphin and Selected Derivatives.

The endogenous peptide kyotorphin (KTP) has been extensively studied since it was discovered in 1979. The dipeptide is distributed unevenly over the brain but the majority is concentrated in the cerebral cortex. The putative KTP receptor has not been identified yet. As many other neuropeptides, KTP clearance is mediated by extracellular peptidases and peptide transporters. From the wide spectrum of biological activity of KTP, analgesia was by far the most studied. The mechanism of action is still unclear, but researchers agree that KTP induces Met-enkephalins release. More recently, KTP was proposed as biomarker of Alzheimer disease. Despite all that, KTP limited pharmacological value prompted researchers to develop derivatives more lipophilic and therefore more prone to cross the blood–brain barrier (BBB), and also more resistant to enzymatic degradation. Conjugation of KTP with functional molecules, such as ibuprofen, generated a new class of compounds with additional biological properties. Moreover, the safety profile of these derivatives compared to opioids and their efficacy as neuroprotective agents greatly increases their pharmacological value.

Monitoring carnosine uptake by RAW 264.7 macrophage cells using microchip electrophoresis with fluorescence detection.

Carnosine, a dipeptide found in a variety of tissues, is believed to possess antioxidant properties. It serves as a scavenger of reactive nitrogen and oxygen species (RNOS), which are important stress mediators of pro-inflammatory conditions and can lead to macrophage activation. In this study, intracellular concentrations of carnosine in murine RAW 264.7 macrophage cells were determined using microchip electrophoresis with laser-induced fluorescence detection following derivatization with naphthalene-2,3-dicarboxaldehyde and cyanide. The method was linear from 25 nM to 5 μM with a limit of detection in cell lysate samples of 65 nM. Using the method of standard additions, the basal intracellular content of carnosine in macrophage cells was determined to be 0.079 ± 0.02 nmol/106 cells. The uptake of carnosine by these cells was then investigated under both physiological and pro-inflammatory conditions. There was a 2.8-fold increase in carnosine uptake for macrophages exposed to lipopolysaccharide and interferon-γ prior to incubation, compared to the controls. This suggests that macrophages may use carnosine uptake as a defense mechanism under pro-inflammatory conditions. Future studies will investigate the role of the carnosine transporter in carnosine uptake and its possible correlation with cell morphological changes observed after stimulation.

Carnosine Attenuates Brain Oxidative Stress and Apoptosis After Intracerebral Hemorrhage in Rats.

Carnosine, an endogenous dipeptide (β-alanyl-L-histidine), exerts multiple neuroprotective properties, but its role in intracerebral hemorrhage (ICH) remains unclear. This study investigates the effect of Carnosine on brain injury using the rat ICH model, which is established by type IV collagenase caudatum infusion. The results indicate that intraperitoneal administration of Carnosine (1000mg/kg) significantly attenuates brain edema, blood-brain barrier (BBB) disruption, oxidative stress, microglia activation and neuronal apoptosis of perihematoma at 72h following ICH in rats models, as convinced by preventing the disruption of tight junction protein ZO-1, occludin and claudin-5, followed by the decrease of ROS, MDA, 3-NT, 8-OHDG level and the increase of GSH-Px and SOD activity, then followed by the decline of Iba-1, ED-1, active caspase-3 and TUNEL positive cells and the decrease of IL-1β, IL-6, TNF-α, active caspase-3 and cytochrome c level. Our results suggest that Carnosine may provide neuroprotective effect after experimental ICH in rat models.

Protective effects of carnosine on dehydroascorbate-induced structural alteration and opacity of lens crystallins: important implications of carnosine pleiotropic functions to combat cataractogenesis

The high level of dehydroascorbic acid (DHA) in the lenticular tissue is an important risk factor for the development of age-related cataracts. In this study, the effects of DHA on structure and function of lens crystallins were studied in the presence of carnosine using gel mobility shift assay, different spectroscopic techniques, and lens culture analysis. The DHA-induced unfolding and aggregation of lens proteins were largely prevented by this endogenous dipeptide. The ability of carnosine to preserve native protein structure upon exposure to DHA suggests the essential role of this dipeptide in prevention of the senile cataract development. Although the DHA-modified α-crystallin was characterized by altered chaperone activity, functionality of this protein was significantly restored in the presence of carnosine. The increased proteolytic instability of DHA-modified lens proteins was also attenuated in the presence of carnosine. Furthermore, the assessment of lens culture suggested that DHA can induce significant lens opacity which can be prevented by carnosine. These observations can be explained by the pleiotropic functions of this endogenous and pharmaceutical compound, notably by its anti-glycation and anti-aggregation properties. In summary, our study suggests that carnosine may have therapeutic potential in preventing senile cataracts linked with the increased lenticular DHA generation, particularly under pathological conditions associated with the oxidative stress.

Carnosine and Homocarnosine Degradation Mechanisms by the Human Carnosinase Enzyme CN1: Insights from Multiscale Simulations.

The endogenous dipeptide l-carnosine, and its derivative homocarnosine, prevent and reduce several pathologies like amytrophic lateral sclerosis (ALS), Alzheimer's disease, and Parkinson's disease. Their beneficial action is severely hampered because of the hydrolysis by carnosinase enzymes, in particular the human carnosinase, hCN1. This belongs to the metallopeptidase M20 family, where a cocatalytic active site is formed by two Zn(2+) ions, bridged by a hydroxide anion. The protein may exist as a monomer and as a dimer in vivo. Here we used hybrid quantum mechanics/molecular mechanics simulations based on the dimeric apoenzyme's structural information to predict the Michaelis complexes with l-carnosine and its derivative homocarnosine. On the basis of our calculations, we suggest that (i) l-carnosine degradation occurs through a nucleophilic attack of a Zn(2+)-coordinated bridging moiety for both monomer and dimer. This mechanistic hypothesis for hCN1 catalysis differs from previous proposals, while it is in agreement with available experimental data. (ii) The experimentally measured higher affinity of homocarnosine for the enzyme relative to l-carnosine might be explained, at least in part, by more extensive interactions inside the monomeric and dimeric hCN1's active site. (iii) Hydrogen bonds at the binding site, present in the dimer but absent in the monomer, might play a role in the experimentally observed higher activity of the dimeric form. Investigations of the enzymatic reaction are required to establish or disprove this hypothesis. Our results may serve as a basis for the design of potent hCN1 inhibitors.

Can Carnosine Prevent the Aging-Induced Changes of Blood Platelet and Brain Regional Monoamine Oxidase-A mRNA in Relation to its Activity?

It is well known that the monoamine oxidase (MAO) activity deregulates during aging along with anti-oxidant activity. Carnosine (β-Ala-l-His) is an endogenous dipeptide biomolecule, having both anti-oxidant and anti-glycating properties. The present study deals with the effect of carnosine on aging-induced changes in MAO-A mRNA expression of brain regions and blood platelets in relation to their MAO-A activity. Results showed that aging significantly and characteristically increased the brain regional MAO-A mRNA whereas, in blood platelets it was significantly reduced with an increase in blood platelet counts. Carnosine attenuated both aging-induced (i) increase in brain regional MAO-A mRNA expression and blood platelet count, (ii) decrease in blood platelet MAO-A mRNA expression and its (platelet MAO-A) activity without affecting the young rats’ brain regions and platelet. The present results thus suggest that carnosine attenuated and restored the aging-induced (a) increase of platelet count and (b) changes in brain regional and blood platelet MAO-A mRNA expression and (c) decrease in platelet MAO-A activity, towards their respective basal level that were observed in young rats.

L-carnosine enhanced reproductive potential of the Saccharomyces cerevisiae yeast growing on medium containing glucose as a source of carbon.

Carnosine is an endogenous dipeptide composed of β-alanine and l-histidine, which occurs in vertebrates, including humans. It has a number of favorable properties including buffering, chelating, antioxidant, anti-glycation and anti-aging activities. In our study we used the Saccharomyces cerevisiae yeast as a model organism to examine the impact of l-carnosine on the cell lifespan. We demonstrated that l-carnosine slowed down the growth and decreased the metabolic activity of cells as well as prolonged their generation time. On the other hand, it allowed for enhancement of the yeast reproductive potential and extended its reproductive lifespan. These changes may be a result of the reduced mitochondrial membrane potential and decreased ATP content in the yeast cells. However, due to reduction of the post-reproductive lifespan, l-carnosine did not have an influence on the total lifespan of yeast. In conclusion, l-carnosine does not extend the total lifespan of S. cerevisiae but rather it increases the yeast’s reproductive capacity by increasing the number of daughter cells produced.

Protective effects of L-carnosine on CCl4 -induced hepatic injury in rats.

The present study was undertaken to investigate the possible protective effect of L-carnosine (CAR), an endogenous dipeptide of alanine and histidine, on carbon tetrachloride (CCl4)-induced hepatic injury. Liver injury was induced in male Sprague-Dawley rats by intraperitoneal (i.p.) injections of CCl4, twice weekly for six weeks. CAR was administered to rats daily, at dose of 250 mg/kg, i.p. At the end of six weeks, blood and liver tissue specimens were collected. Results show that CAR treatment attenuated the hepatic morphological changes, necroinflammation and fibrosis induced by CCl4, as indicated by hepatic histopathology scoring. In addition, CAR treatment significantly reduced the CCl4-induced elevation of liver-injury parameters in serum. CAR treatment also combatted oxidative stress; possibly by restoring hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) levels. Moreover, CAR treatment prevented the activation of hepatic stellate cells (HSCs), as indicated by reduced α-smooth muscle actin (α-SMA) expression in the liver, and decreased hepatic inflammation as demonstrated by a reduction in hepatic tumor necrosis factor-α (TNF-α) and restoration of interleukin-10 (IL-10) levels. In conclusion, CCl4-induced hepatic injury was alleviated by CAR treatment. The results suggest that these beneficial, protective effects are due, at least in part, to its anti-oxidant, anti-inflammatory and anti-fibrotic activities.

The effect of Gly–Gln [ß-endorphin30–31] on morphine-evoked serotonin and GABA efflux in the nucleus accumbens of conscious rats

Glycyl-L-glutamine (Gly–Gln; β-endorphin30–31) is an endogenous dipeptide synthesized through the post-translational processing of β-endorphin1–31. Central Gly–Gln administration inhibits the rewarding properties of morphine and attenuates morphine tolerance, dependence and withdrawal although it does not interfere with morphine analgesia. In an earlier study, we found that Gly–Gln inhibits morphine-induced dopamine efflux in the nucleus accumbens (NAc), consistent with its ability to inhibit morphine reward. To further investigate the mechanism responsible for its central effects we tested whether i.c.v. Gly–Gln administration influences the rise in extracellular serotonin and GABA concentrations evoked by morphine in the NAc. Conscious rats were treated with Gly–Gln (100nmol/5μl) or saline i.c.v. followed, 2min later, by morphine (2.5mg/kg) or saline i.p. and extracellular serotonin and GABA concentrations were analyzed by microdialysis and HPLC. Morphine administration increased extracellular serotonin and GABA concentrations significantly within 20min, as shown previously. Unexpectedly, Gly–Gln also increased extracellular serotonin concentrations significantly in control animals. Combined treatment with Gly–Gln+morphine also elevated extracellular serotonin concentrations although the magnitude of the response did not differ significantly from the effect of Gly–Gln or morphine, given alone suggesting that Gly–Gln suppressed morphine induced serotonin efflux. Gly–Gln abolished the morphine-induced rise in extracellular GABA concentrations but had no effect on extracellular GABA when given alone to otherwise untreated animals. These data show that Gly–Gln stimulates NAc serotonin efflux and, together with earlier studies, support the hypothesis that Gly–Gln inhibits the rewarding effects of morphine by modulating morphine induced dopamine, GABA and serotonin efflux in the NAc.

Abnormal O-GlcNAcylation of Pax3 Occurring from Hyperglycemia-Induced Neural Tube Defects Is Ameliorated by Carnosine But Not Folic Acid in Chicken Embryos.

Neural tube defects (NTDs) are among the most common of the embryonic abnormalities associated with hyperglycemic gestation. In this study, the molecular mechanisms of embryonic neurogenesis influenced by hyperglycemia was investigated using chicken embryo models. High-concentration glucose was administered into chicken eggs and resulted in increased plasma and brain tissue glucose, and suppressed expression of glucose transporters (GLUTs). The rate of NTD positively correlated with hyperglycemia. Furthermore, abnormally increased O-GlcNAcylation, a nutritionally responsive modification, of the key neural tube marker Pax3 protein led to the loss of this protein. This loss was not observed in a folate-deficiency NTD induced by methotrexate. Carnosine, an endogenous dipeptide, showed significant recovery effects on neural tube development. In contrast, folic acid, a well-known periconceptional agent, surprisingly showed relatively minimal effect. Higher expression levels of the Pax3 protein were found in the carnosine-treated groups, while lower expression levels were found in folic acid groups. Furthermore, the abnormal O-GlcNAcylation of the Pax3 protein was restored by carnosine. These results suggest new insights into using endogenous nutrients for the protection of embryonic neurodevelopment affected by diabetes gestation. The abnormal excessive O-GlcNAcylation of Pax3 may be responsible for the neural tube defects associated with hyperglycemia.

Carnosine reverses the aging-induced down regulation of brain regional serotonergic system

The purpose of the present investigation was to study the role of carnosine, an endogenous dipeptide biomolecule, on brain regional (cerebral cortex, hippocampus, hypothalamus and pons-medulla) serotonergic system during aging. Results showed an aging-induced brain region specific significant (a) increase in Trp (except cerebral cortex) and their 5-HIAA steady state level with an increase in their 5-HIAA accumulation and declination, (b) decrease in their both 5-HT steady state level and 5-HT accumulation (except cerebral cortex). A significant decrease in brain regional 5-HT/Trp ratio (except cerebral cortex) and increase in 5-HIAA/5-HT ratio were also observed during aging. Carnosine at lower dosages (0.5–1.0μg/Kg/day, i.t. for 21 consecutive days) didn't produce any significant response in any of the brain regions, but higher dosages (2.0–2.5μg/Kg/day, i.t. for 21 consecutive days) showed a significant response on those aging-induced brain regional serotonergic parameters. The treatment with carnosine (2.0μg/Kg/day, i.t. for 21 consecutive days), attenuated these brain regional aging-induced serotonergic parameters and restored towards their basal levels that observed in 4 months young control rats. These results suggest that carnosine attenuates and restores the aging-induced brain regional down regulation of serotonergic system towards that observed in young rats’ brain regions.

Antihypoxic activity of cycloprolylglycine analogs.

We studied antihypoxic activity of analogs of endogenous cyclic dipeptide cycloprolylglycine in a mouse model of normobaric hypoxia with hypercapnia and found that antixypoxic effect depends on the structure of the substance. It was shown that different pharmacophores are responsible for the antihypoxic, nootropic, and anxiolytic effects of cycloprolylglycine.

Protective effect of carnosine on febrile seizures in immature mice

Febrile seizures (FSs) are the most common type of convulsions in childhood and complex FSs represent an increased risk for development of temporal lobe epilepsy. The aim of this study was to analyze the anticonvulsant effects of carnosine, an endogenous dipeptide composed of alanine and histidine, on hyperthermia induced seizure in immature mice. Injection of carnosine significantly increased the latency and decreased the duration of FSs in a dose-dependent manner. In addition, histidine had similar effects on FSs as carnosine. The protective effect of carnosine or histidine was completely abolished by α-fluoromethylhistidine (α-FMH), a selective and irreversible histidine decarboxylase inhibitor, or in histidine decarboxylase deficient (HDC-KO) mice. Peripheral carnosine administration increased the level of carnosine, histidine and histamine in the cortex and hippocampus of mice pups, but decreased glutamate contents in the cortex and hippocampus. These results indicate that carnosine can protect against FSs in mice pups through its conversion to histamine, suggesting that it may serve as an efficient anti-FSs drug in the future.