Neuroprotective Effects of Afobazol in Experimental Cerebral Hemorrhage

The study of novel selective anxiolytic afobazol on rats with experimental intracerebral post-traumatic hematoma (cerebral hemorrhage) demonstrated its efficiency in a dose of 5 mg/kg applied by a single or repeated administration for 2 weeks. The preparation significantly decreased the incidence of neurological disturbances in most rats (pareses, paralyses, convulsive movements, lateral posture). The therapeutic course of afobazol improved survival rate. Afobazol improved learning and memory in rats with cerebral hemorrhage in the conditioned passive avoidance test and positively affected motor activity in the open field test, which was documented by significant increase in total motor activity indices. The effects of afobazol were more pronounced after course treatment.

[Effect of afobazole on transmembrane ion currents in mollusk neurons]

The effect of anxiolytic afobazole (2-[2-morpholino)ethylthio]-5-ethoxybenzimidazole dihydrochloride) at concentrations of 1, 10, 100 and 1000 microM on transmembrane calcium, sodium, and potassium (slow and rapid) ion currents in isolated neurons of Lymnaea stagnalis mollusks have been investigated. Afobazole was found to produce a dose-dependent reversible action: the drug increased all ion currents at concentrations below 100 microM and inhibited all ion currents at concentrations from 100 to 1000 microM. Afobazole at high concentrations accelerated the inactivation of slow potassium ion current and reversibly inhibited the fast potassium ion current.

Neuroprotective Properties of Afobazol in Vitro

The effects of a novel selective anxiolytic afobazol on survival of HT-22 neurons were studied in the model of oxidative stress and glutamate toxicity. In both models, the neuroprotective effect of afobazol was established.

[Emotionality and spatio-temporal organization of momentary EEG potentials]

With the aim to reveal features of the neocortical spatiotemporal organization of potentials characteristic of different genetically predetermined emotional levels, momentary values of EEG potentials were analyzed in inbred rats of MR and MNRA strains. A topogram was described by a basic parameter such as its general level (the mean of momentary values of potentials derived from 24 symmetrical electrodes bilaterally implanted into the brain cortex) and a similarity coefficient (correlation between the set of its momentary values and that of a standard topogram). The general level and similarity coefficient values were calculated for a series of successive topograms individually for the right and left hemisphere. Also, right- and left-side power spectra of these series were calculated. In rats of MR strain, significant (p < 0.05) peaks in the general level and similarity coefficient spectra were observed in the delta (2.0 Hz), teta (6.5 Hz) and alpha (9 Hz) frequency bands. In this strain, the general level power was higher at the right side, and the similarity coefficient power displayed the left-side dominance. In rats of MNRA strain, peaks in the delta(2.0 Hz) band coinsided in the general level and similarity coefficient spectra, whereas, independently, the general level spectra had peaks in the theta band (7.0 Hz), and similarity coefficient had peaks at frequencies 3.0, 4.5, and 6.0 Hz. The left-side general level spectral power was higher than the right-side general level spectral power in the delta and lower in the high-frequency theta bands. The similarity coefficient power displayed the left-side dominance for the peaks in the delta (2.0 Hz) and theta (3.0 Hz) bands, and it displayed the right-side dominance for the peaks in the theta (4.5 Hz) band. The specific features of the cortical spatiotemporal organization of potentials revealed in rats of MR and MNRA strains suggest different modes of functioning of at least two systems, reticulo-thalamo-corticaland hippocampo-cortical.

[Studying the mechanisms of ladasten action]

The effect of N-(2-adamantyl)-N-(p-bromophenyl)amine (ladasten) on the behavior of MR and MNRA inbred rats with different emotional-stress reaction (ESR) phenotypes was studied in the conventional open-field test. Ladasten (30 mg/kg, i.p.) produced anxiolytic effect in MR rates, while not influencing MNRA animals. At the same time, a model stress induced disorder in the regulation of 3 H-diazepam binding to the benzodiazepine site of GABA(A) receptor in MR (but not in MNRA) rats. Ladasten administered in the anxiolytic dose prevented stress-induced changes in reception at this site.

[Using aphobazol for treatment of the emotional stress after exposure to ionizing radiation]

Emotional stress after radiation may aggravate the course of radiation-induced diseases. The use of the selective anxiolytic aphobazol (a drug from a mercaptobenzamidasol group) corrects development of adaptive reactions to stress in the blood system and normalizes its compensatory potentialities in animals under conditions of combined influence of intensive long-term emotional stress and low-dose irradiation. In lethally irradiated animals the treatment of stressed animals with aphobazol favourably influenced the course of acute radiation disease, enhanced recovery processes in the blood system, increased the animals' survival. The use of aphobazol completely removed a negative effect of emotional stress in indralin-protected animals. Thus, pharmacological correction of the emotional stress caused by different doses of radiation is not only a symptomatic but also a pathogenetically justified form of treatment.

[Biotransformation of mexidol in inbred BALB/C and C57BL/6 mice]

The pharmacokinetics and biotransformation of mexidol was studied in BALB/C and C57BL/6 mice. The blood plasma contains dealkylated metabolites, and the urine contains glucuronoconjugated derivatives of the drug. The process of glucuronoconjugation more intensively proceeds in C57BL/6 mice than in BALB/C mice.

[DNA macroarray analysis of gene expression changes in rat brain after single administration of 2-aminoadamantane compound]

We have used the Rat Atlas cDNA Array ("BD Bioscience") to assess changes in mRNA expression of 588 genes in rat brain after acute treatment of 2-aminoadamantane compound--Ladasten. Drug exhibits the psychostimulating and anxyolitic actions. The analysis of results of hybridization on macrochips and their corroboration by quantitative real-time RT-PCR has allowed to reveal 12 genes, expression of which changes in response to ladasten in rat brain cells. The GAT3 and CARBH genes should be considered as primary pharmacologically significant targets and the changes of their functional conditions allows to explain the distinct mechanisms of anxyolitic properties of the drug. It was shown that Ladasten induced genes are involved in the different signalling pathways (APC, Rb, PKCIP, PMCA), genes encoding the cytosceletal proteins (Tubal, actin), synaptic proteins (Syn IA&IB, PLP) and metabolism enzymes (Gapdh, NSE). It is possible to assume, that proteins, encoded by the given genes participate in the compensatory and/or neuroplastic adaptation to biochemical effects of Ladasten.

[Analgesic activity of dermorphin and its proline analogs]

Dermorphin (Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2; DM) and its analogs obtained via stereochemical transformation of L-Pro6 to D-Pro6 peptide in DM ([Dpro6]DM) and via dehydration of L-Pro6 peptide ([dHPro6]DM) were characterized with respect to the analgesic activity in rats tested under conditions corresponding to various levels of pain sensitivity organization. The drugs were introduced by intraperitoneal injections in various doses (0.1, 1.0, and 10 mg/kg). In the case of acetic-acid induced convulsions (writhing), DM and [Dpro6]DM produced analgesic action in the minimum dose, while the analogous effect of [dHPro6]DM was observed only in greater doses. In the tail-clamp (Haffner) test, DM and [Dpro6]DM also inhibited nociception while the latter compound was ineffective. In the grid-shock test, [Dpro6]DM showed a higher activity than [dHPro6]DM, whereas DM did not produce analgesic action. Thus, all the studied peptides exhibit pronounced analgesic activity, and the replacement of L-Pro6 in DM by its stereomer D-Pro is more effective than the substitution of dHPro6.

[Comparative analysis of EEG spatial organization in the rats with different level of genetically determinated anxiety under ethanol]

The pecularities of EEG changes in the rats with geneticaly different level of anxiety was studed after ethanol injection. The biopotentials spatial synchronization and entropy in the "high anxious" rats (strain MR) did not increase under low dose; on the contrary the above changes were characteristic for the rats without anxiety signs (strain MNRA). After injection of middle and high ethanol doses the "high anxious" rats as compared with "low anxious" ones had the "simplification" of reaction type--the increase of narrow frequency coherence (i.e. linear biopotentials relationship) and spectral power of theta-activity (5.75-7.25 Hz), which was combined with the decrease of nonlinear biopotential characteristics. This fact is interpreted as the predominance of subcortical mechanisms of the brain functional state regulation over cortical ones. The significant decrease of high frequency EEG components in "high anxious" rats takes place under more high ethanol doses, presumably reflecting the increase of the anxiolytic level of ethanol effect.

[The effect of ladasten on the activity of cAMP-dependent protein kinases and the phosphorylation of proteins in brain cells of rats]

The effect of ladasten (50 mg/kg) on the activity of cAMP-dependent protein kinases (represented by protein kinase A (PKA)) in the soluble protein fraction of rat brain was studied. Changes in the PKA activity were monitored in the initial period of drug action (1-12 h). In this stage, ladasten increased the PKA activity, and the level of phosphorylation of one isoform of the main protein myelin (14 kD) and of the proteolipid protein (30 kD). It is concluded that the pharmacological activity of ladasten is related to both cAMP-dependent and cAMP-independent signaling systems.

Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress

White laboratory male rats, inbred male C57BL/6 and Balb/c mice, and male Wistar rats, all previously divided on the basis of the type of emotional reactivity, were used to compare the effects of ten peptide compounds of the tuftsin family and Selank on the behavioral manifestations of emotional stress created by a conflict situation. Peptides were shown to have positive emotional effects and antistress actions. Individual physiologically significant effects were seen, due to the molecular structures of the study peptides and/or their degradation fragments. The results demonstrate the potential for the synthesis of peptide compounds with predictable directions of pharmacological actions and safe for wide use.

[Effect of ladasten on the proteinase C activity in the rat brain cells]

The effect of ladasten (50 mg/kg) on the activity of protein kinase C (PKC) in rat brain was studied depending on the duration of drug action. In the initial stage of the drug action, the PKC activity in the cytosol fraction of rat brain proteins exhibits a more than twofold increase. The effect is independent of the presence of exogenous Ca2+ and is inhibited by cinnarizine and nifedipine. The optimum Ca2+ concentration is maintained due to the activation of Ca2+ ATPase. It is concluded that the pharmacological activity of ladasten is related to activation of Ca2+ phospholipid-dependent protein kinases.

[Effect of himantane on the rat embryo development]

Himantane introduced via a gastric tube to pregnant rats in a dose of 10, 30, 50, and 100 mg/kg produced a dose-dependent embryotoxic and teratogenic action. An analysis of the experimental results and published data suggests that the embryotoxicity of himantane can be related to its general toxic action upon the organism of pregnant female rats.

Pharmacogenetic study of anxiolytic effects of new cholecystokinin receptor antagonists in animals with different levels of emotionality

Effects of two new peptide antagonists of central cholecystokinin receptors, GB-101 (0.05-0.40 mg/kg) and GB-115 (0.006-0.100 mg/kg), on the behavior of inbred animals differing by the reactions to emotional stress were studied in standard tests for evaluation of tranquilizers. The test drugs dose-dependently increased the total locomotor activity in the open field test in Balb/c mice and had no effect on the behavior of C57Bl/6 mice. GB-101 (0.4 mg/kg) and GB-115 (0.025 and 0.05 mg/kg) produced an anxiolytic effect on MR rats (but not on MNRA rats) in the elevated plus-maze and conflict tests. These data confirm anxioselective effects of the test compounds.

GVS-111 prevents oxidative damage and apoptosis in normal and Down's syndrome human cortical neurons

The neuroprotective activity of a novel N-acylprolyl-containing dipeptide analog of the nootropic 2-oxo-1-pyrrolidine acetamide (Piracetam) designated as GVS-111 (DVD-111/Noopept) was tested in two in vitro models of neuronal degeneration mediated by oxidative stress: normal human cortical neurons treated with H(2)O(2), and Down's syndrome (DS) cortical neurons. Incubation of normal cortical neurons with 50 microM H(2)O(2) for 1h resulted in morphological and structural changes consistent with neuronal apoptosis and in the degeneration of more than 60% of the neurons present in the culture. GVS-111 significantly increased neuronal survival after H(2)O(2)-treatment displaying a dose-dependent neuroprotective activity from 10nM to 100 microM, and an IC(50) value of 1.21+/-0.07 microM. GVS-111 inhibited the accumulation of intracellular free radicals and lipid peroxidation damage in neurons treated with H(2)O(2) or FeSO(4), suggesting an antioxidant mechanism of action. GVS-111 exhibited significantly higher neuroprotection compared to the standard cognition enhancer Piracetam, or to the antioxidants Vitamin E, propyl gallate and N-tert-butyl-2-sulpho-phenylnitrone (s-PBN). In DS cortical cultures, chronic treatment with GVS-111 significantly reduced the appearance of degenerative changes and enhanced neuronal survival. The results suggest that the neuroprotective effect of GVS-111 against oxidative damage and its potential nootropic activity may present a valuable therapeutic combination for the treatment of mental retardation and chronic neurodegenerative disorders.

[Genetic and biochemical approaches to individual sensitivity to drug preparations]

The paper addresses evolution of the concept of individual sensitivity to drugs, based on the new pharmacogenetic and pharmacogenomic approaches. The possibility of geno- and phenotypy of the pharmacodynamic and pharmacokinetic processes, aimed at establishing the parameters ensuring reliable prediction of the individual response of a patient. The promising pharmacogenomic methods will allow to create preparations directly acting upon defective genes or the related products. Factors limiting the development of pharmacogenomic methods, related to the lack of data on the structure and physiological properties of protein products and their metabolites, are considered.

[Pharmacological correction of emotional stress after exposure to ionizing radiation and treatment with a radioprotector indralin]

A possibility to use tranquilizers (aphobazole, phenazepamum) for reducing symptoms of prolonged emotional stress influencing rats after irradiation under treatment with a radioprotector indralin was investigated. It was found that indralin showed the protective effect and activated regenerative processes in the hemopoietic system of animals exposed to doses of 6.0 and 7.0 Gy. The prolonged emotional stress developing in the early periods after the exposure, essentially reduced the favourable action of the radioprotector on restoration of hemopoiesis. The application of tranquilizers stopped the inhibiting action of the emotional stress on the hemopoietic system of the irradiated animals in conditions of radioprotective administering.

Effects of phenazepam in ultralow doses on bioelectric activity of the brain and behavior of rats in various models of anxiety

Phenazepam in ultralow doses produced an anxiolytic effect on male outbred albino rats in the conflict situation and elevated plus-maze models and inhibited theta-activity in EEG, which is typical of tranquilizers. As differentiated from standard doses, phenazepam in this concentration did not affect other frequency bands. Our results suggest that phenazepam in ultralow doses acts as the anxioselective tranquilizer.

Pharmacological activity of phenazepam and flunitrazepam in ultralow doses

Experiments on male outbred albino rats showed that benzodiazepine tranquilizers phenazepam and flunitrazepam in ultralow doses (10(-9)-10(-15) mol/kg) produced an anxiolytic effect in the conflict situation test. This effect was not accompanied by myorelaxing and sedative side effects typical of standard doses of tranquilizers.

[Effect of ladasten on proliferative activity and apoptosis in peripheral blood T-lymphocytes ]

The effects of ladasten (0.1-10 microM) on the proliferative activity, apoptosis, and expression of the apoptosis protein regulators (bcl-2 and p53) was studied in 72-h cultures of T-lymphocytes of human peripheral blood activated by anti-CD3MCA. In the concentration interval from 0.01 to 1 microM, ladasten produced a comitogenic effect. The drug changed neither the activity of caspase 3 and the proportion of cells in the late apoptosis stage (Hoechst 33342 stain test), nor the bcl-2 expression, but increased the p53 expression in the activated cells. Irrespective of the concentration, ladasten protected activated lymphocytes in the cell culture from apoptosis induced by the topoisomerase I inhibitor camptothecin or by hydrogen peroxide (provided that the drug was added to the culture simultaneously with the apoptosis inductor). At the same time, lymphocytes cultivated in the presence of ladasten acquired resistance with respect to apoptosis induced by hydrogen peroxide, but not by camptothecin. It is suggested that the immunomodulant activity of ladasten are related to the comitogenic effect and the increase in resistance of the activated T-lymphocytes with respect to non-receptor-induced apoptosis.

[The original novel nootropic and neuroprotective agent noopept]

The paper describes pharmacological properties of the new nootropic drug noopept created using an original approach based on the imitation of a nonpeptide nootrope structure by means of the short-peptide design. In particular, the structure of pyracetam was designed using dipeptide nootropes. Experimental investigations of noopept (N-phenylacetyl-L-polyglycine ethyl ester) showed that the new drug exceeds pyracetam both with respect to the effective dose level (1000 times lower for noopept than for pyracetam) and in the spectrum of mnemotropic activity. In contrast to pyracetam facilitating only the early stages of the memory process, noopept positively influences the memory consolidation and retrieval steps as well. The new drug produces an additional selective anxiolytic action. The pronounced neuroprotective effect of noopept was demonstrated both in vivo (in cases of various forms of brain ischemia) and in vitro (on various neuronal models). The drug action is based on the antioxidant effect, the antiinflammatory action, and the ability to inhibit the neurotoxicity of excess calcium and glutamate, and to improve the blood rheology. It was established for the first time that the activity of noopept is retained both upon parenteral introduction and upon peroral administration, which is a principal advantage of this proline-containing dipeptide over other, more complex peptides. This property provided a basis for the development of a medicinal form of noopept for peroral usage. At present, noopept tablets (noopept 5 and 10 mg) are under clinical assessment as a means of treating cognitive deficiency of cerebrovascular and post-traumatic origin.