Carnosine is a neuroprotective dipeptide consisting of β-alanine and L-histidine. It demonstrates a number of useful features, including stimulation of brain and muscle microcirculation and a rejuvenating effect on cultured cells. Its activity is based on its antioxidant and antiglycating action that, in addition to heavy metal chelation and pH-buffering ability, makes carnosine an essential factor for preventing neurodegeneration and accumulation of senile features. Recently, carnosine was successfully used to treat patients after brain stroke or patients with Parkinson disease. We conclude that carnosine can be recommended for patients under oxidative stress as a natural remedy having high efficiency and no side effects.

NMDA receptors play a crucial role in regulating synaptic plasticity and memory. Activation of NMDA receptors changes intracellular concentrations of Na(+) and K(+), which are subsequently restored by Na/K-ATPase. We used immunochemical and biochemical methods to elucidate the potential mechanisms of interaction between these two proteins. We observed that NMDA receptor and Na/K-ATPase interact with each other and this interaction was shown for both isoforms of α subunit (α1 and α3) of Na/K-ATPase expressed in neurons. Using Western blotting, we showed that long-term exposure of the primary culture of cerebellar neurons to nanomolar concentrations of ouabain (a cardiotonic steroid, a specific ligand of Na/K-ATPase) leads to a decrease in the levels of NMDA receptors which is likely mediated by the α3 subunit of Na/K-ATPase. We also observed a decrease in enzymatic activity of the α1 subunit of Na/K-ATPase caused by NMDA receptor activation. This effect is mediated by an increase in intracellular Ca(2+). Thus, Na/K-ATPase and NMDA receptor can interact functionally by forming a macromolecular complex which can be important for restoring ionic balance after neuronal excitation. Furthermore, this interaction suggests that NMDA receptor function can be regulated by endogenous cardiotonic steroids which recently have been found in cerebrospinal fluid or by pharmacological drugs affecting Na/K-ATPase function.

The interaction of glutamate with various receptors in glutamatergic neurons and functional interaction between glutamate receptors are reviewed. It is hypothesized that metabotropic receptors perform defensive functions in the brain by protecting neurons from neurotoxic effects caused by excessive glutamate release.

A new cardioplegic solution based on three natural dipeptides was developed and introduced at the Laboratory of Cardioplegia, A. N. Bakulev Research Center of Cardiovascular Surgery. The electrolyte composition of the solution corresponded to the category of intracellular cardioplegic solutions. The results of 60 experiments on isolated rat hearts were analyzed for choosing the optimal concentration of sodium ions (35, 60, or 80 mmol/liter). The composition of the studied cardioplegic solutions was selected by ion concentrations in the intra- and extracellular fluid. Earlier and most effective recovery of cardiac function with minimum rhythm and conductivity disorders was observed in the group treated with cardioplegic solution with sodium ion concentration of 60 mmol/liter.

Hyperhomocysteinemia is a risk factor for a number of neurodegenerative and cardiovascular diseases. We have shown that homocysteine induces excitotoxic effects in cells expressing glutamate receptors of the NMDA class. These receptors were found not only in neurons but also in immune-competent cells, neutrophils, red blood cells, cardiomyocytes, and osteoblasts. Activation of these cells by homocysteine results in an increase in cytoplasmic calcium ions, accumulation of reactive oxygen species, and activation of MAP kinase. An overload of immune-competent cells activates both necrotic and apoptotic cell death, whereas the neuropeptide carnosine (an antioxidant and immune modulator) protects cells against both processes. In a model of prenatal hyperhomocysteinemia in rats, we have found that carnosine protects animals against homocysteine toxicity with no change of the blood homocysteine levels. The efficiency of carnosine has also been demonstrated in clinical trials of chronic brain ischemia and Parkinson's disease.

It is known that ouabain, a selective inhibitor of Na/K‐ATPase, not only can cause the activation of signal cascades, which regulate the cell viability, but also can cause the accumulation of free radicals, which can evoke the oxidative stress. We have shown that the nanomolar concentrations of ouabain result in the temporary increase in the level of intracellular free radicals, but the millimolar concentration of ouabain induces a stable intracellular accumulation of free radicals in rat thymocytes. The increasing level of free radicals resulting from both low and high concentrations of ouabain can be attenuated by the antioxidant, carnosine. Moreover, the long‐term incubation with ouabain leads to the cell death by necrosis and apoptosis. Ouabain‐mediated apoptosis and necrosis were also abolished by carnosine. Copyright © 2012 John Wiley & Sons, Ltd.

Carnosine (β-alanyl-l-histidine) was discovered in 1900 as an abundant non-protein nitrogen-containing compound of meat. The dipeptide is not only found in skeletal muscle, but also in other excitable tissues. Most animals, except humans, also possess a methylated variant of carnosine, either anserine or ophidine/balenine, collectively called the histidine-containing dipeptides. This review aims to decipher the physiological roles of carnosine, based on its biochemical properties. The latter include pH-buffering, metal-ion chelation, and antioxidant capacity as well as the capacity to protect against formation of advanced glycation and lipoxidation end-products. For these reasons, the therapeutic potential of carnosine supplementation has been tested in numerous diseases in which ischemic or oxidative stress are involved. For several pathologies, such as diabetes and its complications, ocular disease, aging, and neurological disorders, promising preclinical and clinical results have been obtained. Also the pathophysiological relevance of serum carnosinase, the enzyme actively degrading carnosine into l-histidine and β-alanine, is discussed. The carnosine system has evolved as a pluripotent solution to a number of homeostatic challenges. l-Histidine, and more specifically its imidazole moiety, appears to be the prime bioactive component, whereas β-alanine is mainly regulating the synthesis of the dipeptide. This paper summarizes a century of scientific exploration on the (patho)physiological role of carnosine and related compounds. However, far more experiments in the fields of physiology and related disciplines (biology, pharmacology, genetics, molecular biology, etc.) are required to gain a full understanding of the function and applications of this intriguing molecule.

A primary culture of murine cerebellar neurons was used to induce oxidative stress resulting in the accumulation of reactive oxygen species (ROS) and activation of ERK 1/2 kinase. Short-term incubation (15 min) of cerebellar neurons with homocysteine (HC) or N-methyl-D-aspartate (NMDA) induced partial ERK 1/2 phosphorylation thus providing the activation of the enzyme. Inhibitors of NMDA receptors, MK-801 or D-AP5, both prevented the activation of cells by HC or NMDA. Another receptor-dependent means of oxidative stress stimulation is exposure of cells to the cardiac glycoside ouabain, a specific inhibitor of Na/K-ATPase. Ouabain induces ROS accumulation and substantial ERK1/2 activation in neuronal cells at concentrations as low as 1 nM - 1 M, which corresponds to participation of Na/K-ATPase in intracellular signalling. Neuropeptide carnosine added to the cells 2 hours before oxidative stress prevented both ROS accumulation and ERK1/2 activation. As ERK1/2 kinase plays a key role in gene expression responsible for either cell adaptation or cell death, the model used gives a useful tool to characterize the effect of natural and synthetic anti-cancer drugs on cellular life. The data presented show that carnosine is a natural modulator of oxidative stress in neuronal cells, providing regulation of ERK1/2 activity via buffering intracellular ROS levels.

The levels of polyamines (putrescine, spermine, spermidine) in erythrocytes from patients with hypertonic discirculatory encephalopathy are reduced (by 37, 45, and 50%, respectively) in comparison with the corresponding parameters in the control group. Addition of carnosine to the treatment protocol for chronic brain ischemia normalized the content of putrescine and spermine. The mechanisms of carnosine influence on polyamine metabolism are discussed: trapping of acrolein, end-product of polyamine oxidation, and compensation of NMDAreceptor excitotoxicity.

The study was undertaken to determine the mechanism of carnosine effect on cell proliferation. We studied the effect of carnosine and its derivatives on cell cycle progression in cultured rat pheochromocytoma cells (PC-12). It was found that 48-h incubation of PC-12 cells with carnosine in concentrations of 10-50 mM led to deceleration of cell proliferation, reduction of G0/G1 peak, and accumulation of S- and G2/M-phase cells. Methylation of the carnosine molecule by 1N-position of the imidazole ring potentiated its effect on cell proliferation. Acetylation of the carnosine molecule by free β-amino group attenuated its effect.

Carnosine is a known protector of neuronal cells against oxidative injury which prevents both apoptotic and necrotic cellular death. It was shown earlier that carnosine serves as an intracellular buffer of free radicals. Using the model of ligand-dependent oxidative stress in neurons, we have shown that homocysteine (HC) initiates long-term activation of extracellular signal regulated kinase, isoforms 1 and 2 (ERK 1/2) and Jun N-terminal kinase (JNK) which corresponds to exitotoxic effect resulting in cellular death. L-carnosine (β-alanyl-L-histidine) protects neurons from both excitotoxic effect of homocysteine and cellular death. Its analogs, β-alanyl-D-histidine (D-carnosine) and L-histidyl-β-alanine, restricted accumulation of free radicals and delayed activation of ERK1/2 and JNK in neuronal cells, but did not promote neuronal viability.

This review presents analysis of literature data indicating the presence of NMDA-type glutamate receptors in several types of immune competent cells such as thymocytes, lymphocytes, and neutrophils. The possible role of these receptors in the function of these cells is discussed. The interaction of the receptors with certain ligands circulating in the blood-stream and their role in modulation of immune function is described. It is suggested that homocysteine acts as modulator of these receptors, and its toxicity is largely explained by hyperactivation of the NMDA-type glutamate receptors.

Guanidinium p-nitrophenolate (GUNP), a novel organic compound, was synthesized and crystals were grown from methanol solution by a slow evaporation solution growth technique. A single crystal X-ray diffraction study elucidated the crystal structure of GUNP belonging to the orthorhombic crystal system with space group Pnma. Thermal studies revealed that the GUNP crystal is thermally stable up to 192 °C. The lower cut-off wavelength of GUNP was found to be 505 nm by UV–vis–NIR spectral studies. The luminescence properties of the GUNP crystal were investigated. The three independent tensor coefficients ε11, ε22 and ε33 of the dielectric permittivity were calculated. The mechanical properties of the grown crystal were studied by Vickers׳ microhardness hardness technique.

We have found that neutrophils begin to express NMDA receptors on their membranes after in vivo activation. These receptors are the target for action of homocysteine (HC). After incubation of activated neutrophils with HC, the degranulation process is stimulated and generation of reactive oxygen species is increased. We conclude that expression of NMDA receptors on neutrophil membrane makes neutrophils sensitive to HC. Thus, hyperhomocysteinemia may induce additional stimulation of immune competent cells.

This paper deals with the justification of a new hypothesis that in the of transition of NMDA receptors from normal into excitotoxicic functioning the decisive role plays the time coarse of activation of specific MAP kinase, which is sensitive to the extracellulary factors, ERK 1/2 (extracellulary regulated kinase, isoforms 1 and 2). As it is known, specific agonist of these receptors, N-methyl-D-aspartate (NMDA) challenges the short term activation of this kinase, which leads not to the neuronal cell death but to cell adaptation, while the neurotoxin homocysteine under the same conditions induces the long term activation of ERK 1/2 kinase and correspondingly leads to the massive cells death. Intracellular buffer of free radicals, neuropeptide carnosine (β-alanyl-L-histidine) transforms the excitotoxic response of the receptors to homocysteine into the normal one, correspondingly saves the cells from necrotic death. We suppose that the same exitotoxic mechanism takes place during stroke development resulting in neuronal death, and all the substances, which are able to transform MAPK activation from the continuous regime into transitory one, might be considered as effective neuron protectors from the oxidative damage and thus be used in stroke therapy.

Incubation of rat lymphocytes with homocysteine (HC) or homocysteic acid (HCA) was found to increase the stationary levels of free radicals in lymphocytes, the effect of both ligands being mediated by ionotropic receptors activated by N‐methyl‐D‐aspactic acid (NMDA), the expression of which on rat lymphocyte membranes was earlier demonstrated. In agreement with these data, increase of free radicals in the lymphocyte cytoplasm is preceded by an increase in the intracellular calcium levels, activation of protein kinase C, nicotinamide adenine dinucleotide phosphate oxidase and/or nitric oxide synthase. Both HC and HCA increase the production of IFN‐γ and TNF‐α by lymphocytes and antagonist of NMDA receptors; MK‐801 prevents this effect. The data presented show that rat lymphocyte membrane contains functionally active NMDA receptors, which regulate cytokine accumulation. Copyright © 2011 John Wiley & Sons, Ltd.

The synthetic tripeptide pinealon (Glu-Asp-Arg) demonstrates dose-dependent restriction of reactive oxygen species (ROS) accumulation in cerebellar granule cells, neutrophils, and pheochromocytoma (PC12) cells, induced by oxidative stress stimulated by receptor-dependent or -independent processes. At the same time, pinealon decreases necrotic cell death measured by the propidium iodide test. The protective effect of pinealon is accompanied with a delayed time course of ERK 1/2 activation and modification of the cell cycle. Because restriction of ROS accumulation and cell mortality is saturated at lower concentrations, whereas cell cycle modulation continues at higher concentrations of pinealon, one can conclude that besides its known antioxidant activity, pinealon is able to interact directly with the cell genome.

OBJECTIVENew ways of supplementary or combinatory therapy of rheumatoid arthritis (RA) are of great importance. The aim is to find an additive to classical RA therapy with natural molecules without side effects possessing anti-inflammatory and anti-oxidative properties. In this study we investigated the anti-oxidative and anti-inflammatory properties of the endogenous natural compound carnosine (CARN) in vitro and in vivo. Moreover, we tested also the inhibitory properties of the drug methotrexate (MTX) on dynamic viscosity of hyaluronan (HA) solutions in the same manner.METHODSFor in vitro testing of the inhibitory properties of CARN against degradation of HA solutions, we used the model of degradation of hyaluronan (HA) induced by free radicals. Both substances, CARN and MTX, were compared to glutathione (GSH). Rotational viscometry was used in evaluation of protective properties of compounds studied. The ability of CARN to restore the redox imbalance occurring in adjuvant arthritis (AA) of rats was also tested. We monitored the effect of CARN on hind paw volume (HPV) and on the levels of protein carbonyls, and thiobarbituric acid reacting substances (TBARS) in AA.RESULTSIn the reaction system with the prevalence of •OH and/or peroxy-type radicals, CARN in 200 μmol/L concentration tested was shown to exert a protective action on HA degradation. MTX was less effective than CARN in preventing HA degradation. Its ability to protect HA against radical degradation was evident only at the highest concentration of 400 μmol/L. In AA, carnosine significantly reduced TBARS and protein carbonyls in plasma, and also decreased the HPV of animals most effectively on the day 14.CONCLUSIONSCARN proved its inhibitory properties against degradation of HA solutions at experimental conditions in vitro and showed its beneficial efficiency in vivo. Moreover, it reduced also HPV, the clinical marker of inflammation in AA.

This study investigated the effect of antioxidants, i.e., carnosine and its Trolox- (water-soluble analog of alpha-tocopherol) acylated derivatives (S,S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carbonyl-beta-alanyl-L-histidine (S,S-Trolox-carnosine, STC) and (R,S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carbonyl-beta-alanyl-L-histidine (R,S-Trolox-carnosine, RTC) on the life span of the fruit fly Drosophila melanogaster. Adding carnosine to foodstuff was accompanied and followed by a 20% increase in the average life span of males, but it did not influence the average life span of females. At the same time, adding STC to foodstuff prolonged average longevity both in males (by 16%) and females (by 36%), but the addition of RTC to foodstuff had no influence upon the average life span of insects of either gender. The compounds studied have previously been shown to protect neurons of the rat brain from oxidative stress in the descending order of efficiency: RTC > STC > carnosine. The finding obtained in the present study suggests another order of efficacy regarding the effect on life span in male insects: STC > carnosine > RTC (inefficient). No correlation between antioxidant protection of rat neurons and the effect on life span of the fruit fly makes it possible to suppose the presence of additional cellular targets to be acted upon by exposure of D. melanogaster to these compounds.