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A new derivative of 3,7-diazabicyclo[3.3.1]nonane was studied in electrophysiological experiments, which showed high activity as a positive allosteric modulator of AMPA receptors of the CNS. In doses of 0.01 mg/kg this compound significantly improved the memory of experimental animals disturbed by maximal electric shock. The results indicate that this compound is a promising candidate for preclinical and clinical studies as a treatment for a number of psycho-neurological diseases.

In the present study we analyzed uptake of radiolabeled dopamine by intact synaptosomes and purified synaptic vesicles isolated from the dorsal striatum of mice with constitutive inactivation of all three synuclein-coding genes and wild type mice. Synuclein deficiency substantially compromised the uptake of this neurotransmitter by synaptic vesicles whereas had no effect on synaptosomal dopamine uptake.

This study presents the synthesis of binary tetrohydro-γ-carbolines with ditriazol spacers of varying length, which exhibit anticholinesterase and antioxidant activity, as compared to the original Dimebon prototype. Anticholinesterase activity suggests the potential ability of the new compounds to block β-amyloid aggregation induced by anticholinesterase, making them promising candidates for further research preparations for the treatment of Alzheimer's disease. Particular attention should be paid to the conjugate with an intertriazol hexamethylene spacer, which can be regarded as the leading compound in this series.

We measured the level of natural antibodies (nAb) to glutamate and GABA reflecting the balance of excitation and inhibition systems and involved in the adaptation processes in athletes receiving normalized physical activity in the dynamics of training (figure skaters, football players, and people actively involved in sports). It was found that each subject has an individual immunological profile and its parameters change in accordance with the training load. The measured levels of nAbs to GABA and glutamate correlate the physical activity of a person. The surveyed football players were divided into 3 groups according to the results of the analysis. Subjects of the first group had reliably high immunological indices in comparison with the control and were at the peak of physical form; in the third group, low immunological indices relative to the control indicated exhaustion and fatigue. The indicators of the second group corresponded to normal and demonstrated the resource of adaptation to load. The developed method can be used for assessing person's readiness for physical activity.

Using the patch-clamp method in the whole cell configuration, it was shown that external potassium ions play an important role in the regulation of calcium-activated chloride channels (CaCCs). A clear dependence of the conductivity of the СаССs on the external potassium concentration was shown. The effect of external potassium in the range 0-15 mM on the conductivity of chloride channels was significantly greater than the effect it had on other ionic currents (sodium or potassium). There is reason to believe that these changes in the conductivity of CaCCs may contribute to the development of pathophysiological processes such as hypokalemia or hyperkalemia.

A new drug Dimebon which was developed in theInstitute of Physiologically Active Compounds of theRussian Academy of Sciences (IPAC RAS) showsneuroprotective effect and may become the first pharmacological agent that modifies the development ofmolecular and cellular pathogenesis of proteinopathies. Using an

We studied the effect of somatostatin on presinaptic NMDA receptors and postsinaptic GABA, NMDA, and AMPA receptors in rat brain. It was shown that somatostatin inhibits NMDA-induced (45)Ca(2+) uptake into synaptosomes isolated from rat brain cortex (IC50=2.8×10(-11) M). Somatostatin potentiates AMPA receptors and inhibits hippocampal NMDA receptors in the entire range of examined concentrations (10(-14)-10(-7) M); it also potentiates or inhibits GABA receptor currents in a concentration-dependent manner. Our results suggest that somatostatin modulates the function of ionotropic glutamate and GABA receptors and is involved in cognitive and neurodegenerative processes in the mammalian brain.

BACKGROUND AND ОBJECTIVE: Loss of conformation and function of sufficient number of proteins with high aggregation capacity plays an important role in the pathogenesis of many neurodegenerative disorders (NDD). Due to a recent discovery of new array of proteins with the capacity to form aggregates of nonamyloid type, new NDD models as well as a new level of understanding in vivo models which are already exist is needed. DNA/RN A binding proteins - FUS and TDP-43 play a crucial role in the pathogenesis of some forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. The objective of the study was to develop a new ALS transgenic model.In cell culture experiments, we studied mutant FUS proteins capable to form intracellular deposits morphologically similar to those observed in the autopsy material of ALS patients.We created a transgenic mice line, in which a pathogenic form of human FUS protein was expressed in the nervous system. That led to the aggregation of FUS protein in spinal cord and motor neurons with the following degeneration and development of a phenotype, similar to the human ALS disease phenotype, in young grown-up animals. This neurodegenerative phenotype corresponds to a great number of clinical manifestations of human ALS and is an adequate transgenic model of the disease.

The neuroprotective action of hybrid structures based on fullerene C60 with attached proline amino acid has been studied. Hybrid structures contained natural antioxidant carnosine or addends with one or two nitrate groups. It has been shown that all studied compounds had antioxidant activity and decreased the concentration of malondialdehyde in homogenates of the rat brain. Compound 1, which contained the antioxidant carnosine, has been found to be the most effective antioxidant. All compounds except IV and V inhibited the activity of monoamine oxidase B, while compounds I-IV increased the activity of monoamine oxidase A. All investigated compounds inhibited glutamate-induced Ca2+ uptake into synaptosomes of the rat brain cortex. Compound III, containing two nitrate groups, has been found to be the most effective inhibitor. This compound caused a significant increase of the currents of AMPA receptors (AMPA, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid).

The effect of derivatives of arachidonic and docosahexaenoic acids on AMPA receptors in Purkinje cells from the rat cerebellum was studied using the patch-clamp electrophysiological method. It was shown that derivatives of arachidonic acid-arachidonoyl dopamine and docosahexaenoic acid-docosahexaenoyl dopamine and ester of docosahexaenoic acid with ethylene glycol in nanomolar concentrations effectively potentiated the ionic currents caused by activation of AMPA receptors of kainic acid. Ester of docosahexaenoic acid with nitroethylene glycol blocked AMPA receptors, and anandamide (ethanolamide of arachidonic acid) was not effective. A behavioral test showed that docosahexaenoyl dopamine in doses of 0.1-20 mg/kg had no effect on the learning and memory abilities of the animals tested.

SAMP 10 mice with genetically determined senescence (senescence-accelerated mouse prone 10) aged 16 months demonstrated (in comparison to 3-months old animals of the same strain) the following traits typical of old animal: behavior and memory deficiency, exploratory behavior impairment, and elevated level of anxiety. Dimebon administered for a long period of time with drinking water (1.5 mg/kg over 5 months) produced a positive action upon behavior and memory of 16-months-old SAMP 10 mice, optimized exploratory behavior in the open field test, diminished anxiety in elevated plus maze test, and improved retrieval of passive avoidance reaction.

It is established that SAMP10 mice (senescence-accelerated mice prone 10) with genetically determined accelerated senescence at an age of 9-month exhibit (in comparison to 3-month animals of the same strain) the behavior and memory deficits typical of aged animals, namely, reduced locomotor activity elevated anxiety, and disturbances of memory trace retrieval. Nooglutyl in a dose of 20 mg/kg produces a positive effect on the behavior and memory of 9-month old SAMP10 mice. The observed improvements include optimization of the locomotor activity in the open field test, diminished anxiety in elevated plus maze test, and improved retrieval of passive avoidance reflex.

In this work the attempt to estimate a nitric oxide (NO*) role in regulation of the number of pool haemopoietic stem cells at the irradiated mice was made. With this purpose the number of new compounds from dihydrothiazine-thiazoline line was synthesized, their NO-inhibiting activity was investigated in vivo by the method of ESR-spectroscopy of spin trap and their influence on an output endogenous spleen colonies (CFU-S-8) after the total sublethal y-irradiation of mice in a doze of 6 Gy was also investigated. Was shown, that the tested compounds reduced the contents of NO* in a liver tissue of mice which have received an injection of nitric oxide synthesis inductor - lipopolysaccharide, and also increased an output CFU-S-8 forming endogenous colonies in the spleen of the irradiated mice. Received data testify to perceptivity of search radioprotective agents among NO* synthesis inhibitors.

Contemporary methods of treatment of neurodegenerative diseases (NDs) are limited and mainly symptomatic. Despite difference in particular clinical manifestations, NDs have a number of common features, the main of which is death of certain neuron population. The authors suppose that mitochondria and the phenomenon of mitochondrial permeability transition (MPT), playing the key role in cell death, may be a perspective target for the search of drugs with a capability of delaying the neurological deficit associated with NDs. The authors have demonstrated that some neurotoxins which are widely used to model neurodegenerative conditions are able to potentiate or even induce MPT. The neuroprotective effect of widely used cognition-enhancing drugs, such as tacrin, memantine, dimebon, N-acethylserotonine, and extract of Gingko biloba), may also be a result of their interaction with mitochondria. Thus, the search of drugs capable of preventing or breaking the cascade of cell death as a result of MPT suppression and, at the same time, compensating for the impaired brain functions, is very topical.

Derivatives of 2-amino-2-thiazoline exhibit muscarinomimetic properties in model experiments with isolated rat ileum. The activity of compounds strongly depends on the nature of substituents in 5-position of thiazoline ring. The most active spasmogenic compound is 5-iodomethyl-2-amino-2-thiazoline hydroiodide (EC50 = 13 +/- 2 microM). Its effect is very similar to activity of cholinergic agent pilocarpine (EC50 = 14 +/- 4 microM), but "intrinsic activity" parameter a (alpha = 0.87 +/- 0.12) of 5-iodomethyl-2-amino-2-thiazoline was more significant. Ileum contractions induced by this compounds were inhibited by atropine. Derivatives of 2-amino-2-thiazoline (like pilocarpine) were not demonstrated nicotinomimetic properties. These compounds demonstrate very weak anti-AChE activity. For 5-iodomethyl-2-amino-2-thiazoline hydroiodide the IC50 value is 0.39 +/- 0.09 mM.

We measured serum content of autoantibodies to beta-amyloid protein Abeta(1-42), its neurotoxic fragment Abeta(25-35), vasopressin, bradykinin, thrombin, antithrombin III, alpha(2)-macroglobulin, and angiotensin II in patients with various forms of Alzheimer's dementias, including presenile and senile dementias of the Alzheimer type. The ratio of antibradykinin and anti-Abeta(1-42) autoantibody contents differed by 39% in these patients. Our results can be used for the development of a new biochemical method for differential diagnostics of dementias of the Alzheimer type.

Systemic oral administration of NT-0409, a new synthetic agonist of AMPA subtype glutamate receptor, to rats with chronic partial AF64A-induced deprivation of cholinergic functions improved their learning in a Morris water maze. NT-0409 is close to memantine by the effect on learning and, in contrast to cholinomimetic arisept, ensures longer retention of the developed habit.

Beta-amyloid peptide fragment 25-35 potentiated phosphate- and calcium-induced opening of mitochondrial channels and caused swelling of mitochondria (even without exogenous calcium and phosphate). These changes were accompanied by accumulation of lipid peroxidation products in mitochondria. Specific inhibitors of mitochondrial channels ADP and cyclosporine A prevented beta-amyloid peptide-induced swelling of mitochondria. Our findings suggest that potentiation of mitochondrial channel opening is an important component of the neurodegenerative effect of beta-amyloid.

Dimebon, a Russian-made drug, inhibited toxic effects of beta -amyloid on cultured neurons. Excessive accumulation of beta-amyloid in the brain is characteristic of Alzheimer dementias. Antialzheimer preparations tacrine and dimebon improve survival of cerebellar granule cells during long-term incubation with Abeta25-35, the neurotoxic fragment of beta-amyloid. Both preparations can block potential-dependent Ca(2+) entry into neurons by about 20%, which is explained by their selective action on L-type Ca(2+) channels. It was assumed that the neuroprotective effect of dimebon and tacrine against Abeta25-35 partially depends on inhibition of potential-dependent Ca(2+) entry.

The analysis and justification of medicinal chemistry approaches for focused search of novel agents for Alzheimer's disease (AD) and related disorders treatment and prevention have been reviewed. The systematization of modern biochemical and structural date related to the action of physiologically active compounds on the nervous system apparatus engaged in the AD-like disorders pathogenesis was performed. The major attention was paid to the cholinomimetic, anti-amyloid and antimetabolic approaches, basing on the results published in scientific literature in 3-4 last years and results of preclinical and clinical trials, presented in the internet database in the fall of 2000.

The content of autoantibodies to beta-amyloid protein Abeta(1-42), its neurotoxic fragment Abeta(25-35), and neurotransmitters were studied in the blood of patients with presenile Alzheimer's disease and senile dementia of the Alzheimer type. Significant differences in the relative content of autoantibodies to Abeta(1-42)and autoantibodies to biogenic amines were demonstrated. These results can be used for the development of a biochemical method for differential diagnosis of Alzheimer dementias.

A solid-phase enzyme immunoassay procedure for detecting natural antibodies to vasopressin (VP) is developed. For this purpose, a VP antigen is synthesized on polymer matrix. Optimal conditions of enzyme immunoassay for detecting antibodies to this antigen in the sera of donors and patients with systemic lupus erythematosus (SLE) are selected. The level of anti-VP antibodies is constant in donors and shifted in SLE patients. Changes in the level of natural antibodies to VP correlate with immunochemical parameters.

The neurotoxin MPTP induces in human and in some laboratory animals parkinsonism-like neurological disorder, biochemically characterized by selective and irreversible decrease of dopamine content in striatum. The terminal step in the mechanism of neurotoxic action of MPTP is the inhibition of mitochondrial respiratory chain by pyridinium metabolite (MPP+) resulting in energy depletion and nervous cells death. Earlier it was shown that some chemical compounds, in particular diethyldithiocarbamate (DTC), can potentiate MPTP neurotoxicity. In the present work we have studied the influence of DTC derivatives on MPTP neurotoxic effect in vivo and on MPP+ inhibition of mitochondrial respiration (both on intact mitochondria and on submitochondrial particles) in vitro. It was revealed that DTC alone change mitochondrial membrane state by respiratory chain uncoupling and inhibition. DTC and MPP+ mutually potentiate inhibition of electron transport as well. The combined effect of DTC plus MPP+ action on mitochondria respiration reflects the sum of reciprocally leveling and potentiating factors and can explain the order of efficacy of MPTP-neurotoxicity potentiation in vivo in series of close DTC derivatives.

Inhibition of NADH dehydrogenase (Complex I) of the mitochondrial respiratory chain by 1-methyl-4-phenylpyridinium (MPP+) and its analogs results in dopaminergic cell death. In the present study, the inhibition of mitochondrial respiration and of NADH oxidation in inverted inner membrane preparations by the oxidation products of N-methyl-stilbazoles (N-methyl-styrylpyridiniums) are characterized. These nonflexible MPP+ analogs were found to be considerably more potent inhibitors than the corresponding MPP+ derivatives. The IC50 values for these compounds and previously published figures for MPP+ analogs were then used to select a computer model based on structural parameters to predict the inhibitory potency of other compounds that react at the "rotenone site" in Complex I. A series of 12 novel inhibitors different in structure from the basic set were used to test the predictive capacity of the models selected. Despite major structural differences between the novel test compounds and the MPP+ and styrylpyridinium analogs on which the models were based, substantial agreement was found between the predicted and experimentally determined IC50 values. The value of this technique lies in the potential for the prediction of the inhibitory potency of other drugs and toxins which block mitochondrial respiration by interacting at the rotenone sites.

In recent years, sufficient evidence has surfaced to implicate low-molecular-weight organic compounds in certain known neurological disorders. At this time, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is considered the compound capable of inducing conditions most similar to idiopathic parkinsonism in clinical, biochemical, and histopathological characteristics. Substances containing MPTP-like fragments are used as herbicides, drugs and intermediates in the synthesis of many heterocyclic compounds. The mechanistic study of toxic MPTP action has enabled development of criteria for appraising potential parkinsonogenic properties of similar chemical structures. Key features of MPTP action include the following: 1. Ability to pass through the blood-brain barrier (BBB). 2. Enzymatic biotransformation to the neuroactive form (pyridine metabolites). 3. Transfer to neurons via a neuromediator reuptake system. 4. Action on intracellular targets. This review discusses data concerning the effects of metabolite structure on the major steps in the neurotropic action mechanism of MPTP-like compounds. Special attention is focused on the key steps defining the selectivity of MPTP's neuronal action, i.e., the activation step caused by monoamine oxidase (MAO) and interaction with the dopamine (DA) reuptake system. Most structural MPTP analogs (including certain pesticide preparations) used in our experiments and described in the literature exhibit no degenerative MPTP-like properties. This is probably related to the fact that each consecutive stage in the MPTP neurotoxicity mechanism makes rather stringent demands on metabolite structure. The number of structures which concurrently meet the requirements of all the processes is finite. This, however, does not invalidate the hypotheses concerning the ecotoxic nature of idiopathic parkinsonism. Possible ecotoxins may have only a partial, presymptomatic effect which, however, promotes age-related neurodegenerative processes and accelerates development of parkinsonism. This concept necessitates designing special tests of the possible neurotoxic properties of compounds found in the environment which may be functional MPTP analogs.

Possibility of ortho-, para-, meta-methylphenyl and methoxyphenyl-derivates of MPTP to produce parkinsonism was investigated. Only ortho-methylphenyl- and ortho-methoxyphenyl-derivates of MPTP cause a persistent loss in dopamine content in the brain and produced the clinical symptoms of parkinsonism. All substances produced Parkinsonian-like syndrome gives the symptoms of activation of nervous system during 0.5-1 h after injection and symptoms of depression in following 3 h of observations.

Stylbasole analogs of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were studied as monoamine oxidase (MAO) substrates. Dehydrogenation of these compounds was shown to be catalyzed by both serotonine specifical and benzylamine specifical MAO activities. Markedly high affinity of stylbasoles to B type of MAO was found. Influence of substrate structure on its biotransformation effectiveness is realized by the principle--"better binding-worse catalysis". MAO inactivation during the reaction is appeared to be realized as result of product inhibition and perhaps of substrate inhibition.

Kinetic aspects of enzymatic reactions proceeding in the autocatalytic mode are considered. Kinetic analysis of a mechanism with proenzyme-enzyme interaction and of mechanism in which activation involves an interaction with the product of enzymatic reaction is presented. It is shown that these mechanisms are distinguished by the dependences of kinetics of the process on enzyme and substrate concentrations. Method is developed for the determination of concentration of active centers of enzyme in the case of activation by reaction product. Conclusions obtained are illustrated using autocatalytic enzymatic systems such as trypsin-trypsinogen and bacterial hydrogenases-hydrogen-4,4'-dimethylbipyridinium.

Forward and reverse reactions of catalysis by a hydrogenase from T. roseopersicina in steady state have been investigated. The dependance of reaction rate on the concentration of substrates and of hydrogen ions has been studied. Detailed formal-kinetic analysis of possible mechanisms of enzyme action has been carried out and the classification of mechanisms of the reaction has been given. Comparison of experimental data with the equations obtained from formal-kinetic analysis has been undertaken and mechanisms compatible with experimental data were sorted out. Kinetic and molecular mechanism of the catalytic activity of hydrogenase has been proposed and elementary rate constants for the activation of molecular hydrogen have been calculated.

Kinetics of monoamine oxidase (MAO) catalyzed dehydrogenation of neurotropic analogues of biogenic monoamines in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine series were studied. It is shown that methyl substitution in the phenyl ring increases significantly the enzyme-substrate affinity, but the substituent's effect on the catalytic stage largely depends upon its position in the ring. o- and m-Methyl derivatives were preferably oxidized by B type of MAO, whereas p-total derivative was oxidized by B type as well as by A type of the enzyme. In the course of the oxidation reactions MAO is irreversibly inhibited by the dihydropyridinium product of the reaction, particularly in case of methyl derivatives. The significant and structure-dependent inhibition of the enzyme might be responsible for the differences in neurotropic properties of the above substrate homologues.