The effect of rifampicin on expression of the toll-like receptor system genes in the forebrain cortex of rats prenatally exposed to alcohol

Ethanol causes long-term changes in the toll-like receptor (TLR) system, promoting activation of neuroinflammation pathways. Alcohol use during pregnancy causes neuroinflammatory processes in the fetus; this can lead to the development of symptoms of fetal alcohol spectrum disorder (FASD). Our study has shown that prenatal alcohol exposure (PAE) induced long-term changes in the TLR system genes (Tlr3, Tlr4, Ticam, Hmgb1, cytokine genes) in the forebrain cortex of rat pups. Administration of rifampicin (Rif), which can reduce the level of pro-inflammatory mediators in various pathological conditions of the nervous system, normalized the altered expression level of the studied TLR system genes. This suggests that Rif can prevent the development of persistent neuroinflammatory events in the forebrain cortex of rat pups caused by dysregulation in the TLR system.

Prolonged alcohol consumption influences microRNA expression in the nucleus accumbens of the rat brain

The microRNA (miR) species analyzed in this study are involved in molecular mechanisms of TLR4 and TLR7 signaling, mediating the development of neuroinflammation and neurodegeneration. We have investigated the expression levels of miR-let7b, miR-96, miR-182, miR-155, and the mRNA content of HMGB1, TLR3, TLR4 in the nucleus accumbens (NAc) of the brain of rats exposed to long-term alcoholization. The long-term alcoholization caused a decrease in miR-let7b, miR-96, miR-182, and TLR7 mRNA levels; this was accompanied by an increase in miR-155, TLR4, and Hmgb1 mRNA levels in the NAc of rat brain. TLR7 is functionally linked to miR-let7b. The data of a simultaneous decrease in miR-let7b and TLR7 mRNA are of interest for further studies; they may indicate on the lack of functionally significant links between Hmgb1 and the miR-let7b-TLR7 system in NAc. The existing evidence of a functional relationship between TLR4 with miR-155 and miR-182 and our observations on their expression changes during chronic alcoholization are very interesting and require further investigation. The suggestion about the development of neuroinflammatory process in NAc under prolonged alcohol exposure are relevant for studying the level of TLR gene expression in NAc, as well as the expression of miR species, which may have a functional relationship with the TLR system.

Investigation of antiparkinsonian activity of new imidazole-4,5-dicarboxylic acid derivatives on the experimental model of catalepsy

Introduction: To study the antiparkinsonian activity of new ligands of the glutamate NMDA receptor complex – 1,2–substituted imidazole-4,5-dicarboxylic acids – on an experimental model of catalepsy caused by haloperidolintraabdominal injections in rats. Materials and methods: The experiments were performed on Wistar rats weighing 300-350 g, obtained from the Rappolovo nursery of the Russian Academy of Medical Sciences (Leningrad Region). The animals were kept in standard plastic cages in vivarium conditions with free access to water and food at a temperature of 22±2 °C and in the experiment were divided into several groups (6 animals each). All the experiments were carried out in the autumn-winter period. The animals were kept in accordance with the rules of laboratory practice (GLP), regulatory documents ”Sanitary Rules for the Device, Equipment and Maintenance of Vivarium” and the Order of the Ministry of Health and Social Development of the Russian Federation dated 23.08.2010 No. 708n “On Approval of the Rules of Laboratory Practice”. Imidazole-dicarboxylic acid derivatives (IEM-2295, IEM-2296) were injected intraperitoneally at doses from 5 mg/kg to 40 mg/kg simultaneously with haloperidol at a dose of 1 mg/kg, after which the duration and severity of catalepsy were evaluated after 30, 60, 120 minutes from 0 to 6 points according to the Morpurgo method. Results: The severity of catalepsy with the injection of IEM-2295 decreased on average to 3 points, while in the control group it remained at the level of 6 points throughout the observation. However, the severity of catalepsy with the introduction of IEM-2296 decreased to an average of 4 points, but the effect itself lasted longer than with the introduction of IEM-2295. Thus, it was noted that by the 120th minute of observation, the severity of catalepsy in rats receiving the IEM-2295 compound averaged 5 points, whereas in animals receiving IEM-2296 – 3 points. Discussion: Basing on the results of our work and similar experiments, we can conclude that the studied compounds, which are not channel blockers, have an active effect on dopaminergic neurotransmission, because of which the symptoms of catalepsy that occur when haloperidol is injected to rats were stopped to one degree or another. Conclusion: The studied substances exhibit antiparkinsonian activity on an experimental haloperidol model of catalepsy in rats and are promising for development as potential therapies for neurodegenerative diseases. Further study of these compounds and other ligands from the NMDA-blocker group in a wider sample on the catalepsy model, as well as on other models of Parkinsonism, is required. Graphical Abstract

[Interleukin-11 in Pathologies of the Nervous System]

The study of the role of cytokines in various pathological conditions of the body is a topical area in modern biomedicine. Understanding the physiological roles played by cytokines will aid in finding applications for them as pharmacological agents in clinical practice. Interleukin 11 (IL-11) was discovered in 1990 in fibrocyte-like bone marrow stromal cells, but there has been increased interest in this cytokine in recent years. IL-11 has been shown to correct inflammatory pathways in the epithelial tissues of the respiratory system, where the main events occur during SARS-CoV-2 infection. Further research in this direction will probably support the use of this cytokine in clinical practice. The cytokine plays a significant role in the central nervous system; local expression by nerve cells has been shown. Studies show the involvement of IL-11 in the mechanisms of development of a number of pathologies of the nervous system, and therefore it seems relevant to generalize and analyze the experimental data obtained in this direction. This review summarizes information that shows the involvement of IL-11 in the mechanisms of development of brain pathologies. In the near future this cytokine will likely find clinical application for the correction of mechanisms that are involved in the formation of pathological conditions of the nervous system.

[Ginsenosides affect the system of Toll-like receptors in the brain of rats under conditions of long-term alcohol withdrawal]

Long-term alcohol consumption causes the development of neuroinflammation in various brain structures. One of the mechanisms involved in this process is the increased activity of TLR-signaling intracellular pathways. Studies confirm the ability of ginseng extract or its individual ginsenosides to reduce the increased activity of TLR-signaling pathways. The aim of our study was to study the effect of the amount of ginsenosides obtained from the extract of the Panax japonicus cell line on the state of the TLR-signaling system in the nucleus accumbens and hippocampus of the rat brain in a model of long-term alcohol consumption during alcohol withdrawal. The results of the study showed that ginsenosides were able to make changes in the TLR signaling system, which has been altered by long-term alcohol consumption. A significant effect of ginsenosides on the level of TLR3 and TLR4 mRNA in the nucleus accumbens was found, while in the hippocampus, ginsenosides significantly affected the level of TLR7 mRNA. The effect of ginsenosides on the level of mRNA of transcription factors and cytokines involved in TLR-signaling was evaluated. Thus, results of our study confirm that ginsenosides are able to influence the state of TLR-signaling pathways, but this effect is multidirectional in relation to different brain structures. In the future, it seems interesting to evaluate the role of individual ginsenosides in relation to genes of TLR-signaling, as well as the effect of ginsenosides on other brain structures.

Enhanced Aggression, Reduced Self-Grooming Behavior and Altered 5-HT Regulation in the Frontal Cortex in Mice Lacking Trace Amine-Associated Receptor 1 (TAAR1)

The Trace Amine-Associated Receptor 1 (TAAR1) is one of the six functional receptors belonging to the family of monoamine-related G protein-coupled receptors (TAAR1-TAAR9) found in humans. However, the exact biological mechanisms of TAAR1 central and peripheral action remain to be fully understood. TAAR1 is widely expressed in the prefrontal cortex and several limbic regions, interplaying with the dopamine system to modulate the reward circuitry. Recent clinical trials suggest the efficacy of TAAR1 agonists as potential novel antipsychotic agents. Here, we characterize behavioral and neurochemical phenotypes of TAAR1 knockout mice, focusing on aggression and self-grooming behavior that both strongly depend on the monoaminergic signaling and cortico-striatal and cortico-limbic circuits. Overall, we report increased aggression in these knockout mice in the resident-intruder test, accompanied by reduced self-grooming behavior in the novelty-induced grooming test, and by higher cortical serotonin (5-HT) tissue levels. Further studies are necessary to explore whether TAAR1-based therapies can become potential novel treatments for a wide range of neuropsychiatric disorders associated with aggression.

[The effect of rifampicin on the system of Toll-like receptors in the nucleus accumbens of the brain of long-term alcoholized rats during alcohol withdrawal]

Nucleus accumbens (NAc) is the ventral part of the striatum of the brain; it is an important part of the mesolimbic pathway involved in the reward system that mediates the formation of various forms of addiction, in particular alcohol addiction. Neuroimaging data and in vitro studies indicate the development of a pronounced neurodegenerative process in the NAc, with long-term alcohol use, but the key mechanisms mediating this process remain unknown. In recent years, the attention of researchers has been focused on studying the system of Toll-like receptors (TLRs), the increased activity of which is clearly shown in the cerebral cortex and hippocampus during prolonged alcohol exposure, but there is a need to study the role of this system in other brain structures. In this study, we have shown that prolonged alcohol exposure (2 months) with moderate doses of ethanol (2 g/kg) promotes a pronounced increase in the expression of the Tlr4 gene and its endogenous ligand Hmgb1 in NAc during the period of alcohol withdrawal in rats. Injections of rifampicin (100 mg/kg) reduced the elevated expression level of Hmgb1, Tlr4, as well as pro-inflammatory cytokine genes (IL1β, IL6), while the administration of the drug increased the reduced level of mRNA of anti-inflammatory cytokines (IL10, IL11).

[Effect of ethanol on platelet biology]

In recent years, interest in the study of platelets, significantly increased due to recent discoveries providing convincing evidence that their functions by are not limited to their participation in the blood coagulation mechanism. Many works are devoted to the study of the functional state of platelets under conditions of acute and chronic alcohol exposure. The results of such studies can be useful for the development of new markers of the degree of alcohol intoxication of the body for the subsequent choice of the method drug correction of disorders caused by acute or chronic alcohol effects. The review summarizes results in vivo and in vitro of studies performed during more than 60 years on the effect of ethanol on the biogenesis, number, morphology and biochemistry of platelets.

[Prenatal exposure to alcohol alters TLR4 signaling in the prefrontal cortex in rats]

Prenatal alcohol exposure (PAE) can lead to developmental disorders of the central nervous system (CNS) and mental retardation. Toll-like receptor (TLR) 4 plays an important role in the development of defects in the nervous system caused by PAE. However, how PAE affects the TLR4 response in the brain remains unclear. Using the model of semi-forced alcoholization of pregnant rats, we investigated TLR4-mediated signaling on the 30th day of postnatal development in their offspring. Rats exposed to PAE showed a higher expression of proinflammatory cytokines in the prefrontal cortex, but TLR4-mediated signaling in response to lipopolysaccharide (LPS) was weakened. These data suggest that PAE can lead to neuroinflammation and suppression of the TLR4-mediated response to LPS in the prefrontal cortex of young rats. Since innate immunity plays an important role in brain development, PAE-induced suppression of the TLR4-mediated response may be one of the mechanisms for the development of CNS pathology.

Expression of the growth hormone secretagogue receptor 1a (GHS-R1a) in the brain

The review presents data on the expression of growth hormone secretagogue receptor 1a (GHS-R1a) in the brain regions in model animals (zebrafish, rodents, primates), and in the human brain. Studies show widespread distribution of the receptor in the brain, which evidences the involvement of the receptor in many physiological processes. Using various organisms, data have been obtained regarding the participation of the GHS-R1a in the regulation of the anti- and pro-inflammatory response, proliferation, and apoptosis. It is known that the receptor plays an important role in eating behavior and is also involved in the pathogenetic mechanisms of drug addiction, obesity, and chronic alcohol consumption. Based on this, research is underway with the use of various therapeutic agents that can be used for the pharmacological correction of these conditions. This review also presents hypothetical pathways of intracellular signaling, in which GHS-R1a may participate. A complete understanding of these mechanisms has not yet been reached. The ghrelin intracellular signaling seem to be specific to brain region and, probably, also depend on the metabolic or stress status of the organism.

[Increase in the level of orexin receptor 1 (OX1R) mRNA in the brain structures of rats prone to impulsivity in behavior]

Orexin and its receptors are involved in the mechanisms of pathological craving for alcohol and psychoactive drugs. The orexin system is also involved in the mechanisms of non-chemical forms of addiction: binge eating and gambling. The aim of this work was to study the level of orexin receptor mRNA in the hypothalamus, hippocampus, and prefrontal cortex of rats prone to impulsivity in behavior in a model for studying the elements of gambling addiction (a variant of the Iowa Gambling Task test). Brain structures were isolated on the 22nd day of the experiment. The expression of the OX1R gene was higher in the hypothalamus by 122% and in the hippocampus by 149% in rats that preferred to receive a high reward, but with a low probability as compared with a group of animals that preferred a low level of reinforcement, but with a 100% probability. In the prefrontal cortex, on the contrary, no significant changes were observed in the level of OX1R mRNA. The level of OX2R mRNA insignificantly changed in the hypothalamus, hippocampus, and prefrontal cortex of rats prone to impulsivity in behavior. The data indicate involvement of OX1R in the hypothalamus and hippocampus in mechanisms mediating impulsive behavior and the choice of the significance of positive reinforcement in terms of its varying strength and probability.

[Expression of Ghrelin Receptor GHS-R1a in The Brain (Mini Review)]

The review presents data on the expression of ghrelin receptor GHS-R1a in the brain in model animals (Danio rerio, rodents, primates), and in the human brain. Studies show widespread localization of GHS-R1a in the brain, which indicates the involvement of the receptor in many physiological processes. Using various models, information has been obtained regarding the participation of the receptor in the regulation of the pro- and anti-inflammatory response, apoptosis and proliferation. It is known that the ghrelin receptor plays an important role in eating behavior and is also involved in the pathogenetic mechanisms of obesity, drug addiction, and alcoholism. With this in mind, research is underway with the use of various therapeutic agents (receptor agonists and antagonists) that can be used for the pharmacological correction of these pathological conditions. This review also presents hypothetical mechanisms of intracellular signaling, in which GHS-R1a may participate; however, a complete understanding of these mechanisms has not yet been reached. The ghrelin intracellular pathways seem to be specific to brain region and, probably, also depend on the metabolic or stress status of the organism.

[The TLR3 induction increases content of interferons in rat's brain by TRAIL signaling during long-term alcoholization]

The pathogenetic mechanisms associated with alcohol use include dysregulation of the innate immune system mechanisms in the brain. TLR3 expression is increased in the postmortem material of the prefrontal cortex of humans. An increase in the TLR3 signaling activity leads to the induction of interferons (IFN). IFN are associated with depressive symptoms and, therefore, may play a role in the pathogenesis of alcoholism; however, the exact mechanisms of intracellular signaling mediated by the influence of ethanol are not fully elucidated and their study was the purpose of this work. The experimental results showed that ethanol and the TLR3 agonist Poly (I:C) increased the content of TLR3, IFNβ, and IFNγ mRNA in the prefrontal cortex. In addition, expression of the TRAIL encoding gene also increased, and this increase positively correlaed with the mRNA content of TLR3, IFNβ and IFNγ both under alcoholization conditions and after injections of the TLR3 agonist. The data obtained may indicate that alcoholization is able to activate TLR3-TRAIL-IFN-signaling in the prefrontal cortex of the brain.

In search of new brain biomarkers of stress

The aim: of the study was to investigate the level of ghrelin in various brain structures during a stress response in Zebrafish to a predator, to evaluate this indicator as a potential biomarker of stress, and the effect of a benzodiazepine tranquilizer (phenazepam) on stress-induced changes

Materials and methods: The object of the study was Zebrafish, or Danio rerio wild type, which was subjected to stress by exposure to a predator Hypsophrys nicaraguensis from the cichlid family. In the tail tissue, the level of cortisol was determined, in the brain – the level of total (acylated and non-acylated) ghrelin by the method of enzyme-linked immunosorbent assay. The benzodiazepine anxiolytic phenazepam (1 mg/L), a ghrelin antagonist [D-Lys3]-GHRP-6 (0.333 mg/l) and corticotropin-releasing hormone (CRF; 0.4 mg/L) were used as the pharmacological agents.

Results and discussion: Exposure to a predator, just as administering CRF, more than doubled the level of cortisol in the tail tissue. [D-Lys3]-GHRP-6 and phenazepam prevented an increase in a tissue cortisol level. Simultaneously, in the medulla oblongata and cerebellum, the phylogenetically most ancient structures, rather than in the forebrain (telencephalon) or in the midbrain (corpora bigemia), the level of ghrelin was recorded about 500 pg/g of total protein. In response to exposure to a predator, the level of ghrelin increased in the forebrain and midbrain to nanogram concentrations and moderately decreased in the cerebellum. The effect was prevented by phenazepam and [D-Lys3]-GHRP-6.

Conclusion: Increases in ghrelin in the brain in response to stressful situations can be seen as a functional brain biomarker of stress, along with increased levels of tissue cortisol levels. Both of these effects are prevented by both the ghrelin antagonist and the benzodiazepine tranquilizer. The mechanism of action of the tranquilizer is a functional antagonism between the GABAergic system of the brain and the ghrelin system.

[HMGB1gene expression changes in the striatum and amigdal of the rat's brain under alcoholization and ethanol withdrawal]

Intracellular signaling mediated by the HMGB1 protein, an agonist of TLRs, is considered as a possible target for the correction of pathologies of the neuroimmune system, however, the expression level of the Hmgb1 gene has not been previously studied in various brain structures of rats exposed to prolonged alcoholization followed by ethanol withdrawal. The study showed that long-term use of ethanol caused to an increase in the level of Hmgb1 mRNA in the striatum of rat brain. Alcohol withdrawal changed the level Hmgb1 mRNA in the striatum and amygdala on the 1st and 14th day. The data obtained may indicate that in different structures of the brain there are multidirectional changes in the molecular mechanisms of the neuroimmune response with prolonged use of ethanol and its withdrawal.

Pharmacological activity of new imidazole-4,5-dicarboxylic acid derivatives in dopaminergic transmission suppression ttests in mice and rats

Objective: To study the antiparkinsonian activity of new 1,2-substituted imidazole-4,5-dicarboxylic acids in dopaminergic transmission suppression tests in mice and rats.

Materials and methods: On a model of reserpine extrapyramidal disorders, the derivatives of imidazole-dicarboxylic acids (IEM2258, IEM2248, IEM2247) were injected into the lateral brain ventricles of the mice 30 minutes after injecting reserpine at the doses of 0.1–0.5 mmol. Locomotor activity was analyzed in the Open-field test 2 hours later. In the catalepsy model, the studied agents were injected, using a pre-implanted cannula, with a simultaneous intraperitoneal injection of haloperidol. The severity of catalepsy was assessed with the Morpurgo method. Amantadine was used as a comparator drug in all the tests.

Results: It was shown that IEM2258 significantly increased the main indicators of locomotor activity in the Open-field test at all the studied doses. The value of the antiparkinsonian effect of IEM2258 at doses of 0.4–0.5 mmol significantly exceeded that of amantadine. The antiparkinsonian effect of IEM2247 was maximally expressed and was significantly different from those in the control and comparator group at doses of 0.2 and 0.3 mmol. For all the experimental groups, a significant decrease in the manifestations of catalepsy in comparison with control indexes was determined.

Discussion: The results made it possible to suggest the involvement of imidazole-4,5-dicarboxylic acids derivatives in the process of experimental improvement of dopaminergic neuromodulation and efficiency in animals.

Conclusion: The data showed a significant dose-dependent antiparkinsonian activity of new imidazole-4,5-dicarboxylic acid derivatives, which makes it promising to develop these agents and to further search for effective and safe antiparkinsonian drugs in this pharmacological class.

Graphical abstract

[Involvement of TOLL-like receptors in the neuroimmunology of alcoholism]

Alcohol use is a global socially significant problem that remains one of the leading risk factors for disability and premature death. One of the main pathological characteristics of alcoholism is the loss of cognitive control over the amount of consumed alcohol. Growing body of evidence suggests that alterations of neuroimmune communication occurring in the brain during prolonged alcoholization are one of the main mechanisms responsible for the development of this pathology. Ethanol consumption leads to activation of neuroimmune signaling in the central nervous system through many types of Toll-like receptors (TLRs), as well as the release of their endogenous agonists (HMGB1 protein, S100 protein, heat shock proteins, extracellular matrix breakdown proteins). Activation of TLRs triggers intracellular molecular cascades leading to increased expression of the innate immune system genes, particularly proinflammatory cytokines, subsequently causing the development of a persistent neuroinflammatory process in the central nervous system, which results in massive death of neurons and glial cells in the brain structures, which are primarily associated with the development of a pathological craving for alcohol. In addition, some subtypes of TLRs are capable of forming heterodimers with neuropeptide receptors (corticoliberin, orexin, ghrelin receptors), and may also have other functional relationships.

[Ethanol induced increase of fibroblast growth factor 2 mRNA content in emotiogenic brain structures of rats]

We studied the effects of acute, subacute, and chronic alcohol treatment of rats on the content of fibroblast growth factor 2 (FGF2) mRNA in various brain structures. Results suggest a possible role of FGF2 in the functioning of dopaminergic neurons in the midbrain. In our experiment, ethanol treatment of rats was accompanied by an increase in the FGF2 mRNA level in the emotiogenic structures of the brain. This effect was blocked by pretreatment of animals with chlorpromazine. This suggests FGF2 involvement in the mechanisms of alcohol dependence and can be considered as a possible diagnostic and therapeutic target in alcoholism.

[Molecular mechanisms of the cytoprotector cramizol effect in the experimental dyslipidemia model]

The tested drug cramizol exhibits lipid-lowering and anti-atherogenic effects. Cramizol reduces blood cholesterol and triglycerides. It also increases HDL and reduces the atherogenic index in rats with the chronic dyslipidemia model induced by a hypercholesterol diet. Cramizol is effective as a hypolipidemic agent and its efficiency is comparable with the reference drug, phenofibrate. Cramizol increases expression of the ApoA1 and ApoC2 genes, and also reduces expression of the Scarb1 gene in rats with experimentally induced hyperlipidemia. These mechanisms could be the basis of its hypolipidemic and anti-atherogenic actions.

[Effect of etimizole structural analogues on protein kinase CK2, protein phosphorylation and transcription of chromatin in rat brain cortex and hippocampus]

Protein kinase CK2 is an important enzyme in the nervous system. The nuclear forms of CK2 regulate chromatin structure and gene expression, the key processes for long-term memory formation. Memory modulators, the Structural Analogues of Etimizole (SAE), were able to increase or decrease the activity of chromatin-associated CK in the cortex and hippocampus of rat brain in vitro. In vivo memory enhancers from SAE-group (3 mg/kg) stimulated CK2 activity and the transcriptional ability of chromatin in the cortex and hippocampus, starting from 30 min with a peak for 60 min and a duration up to 180 min. At these periods the memory inhibitor from the SAE-group reduced CK2 activity and chromatin transcription. It is assumed that the modulating effect of SAE on CK2 activity and transcription underlies the effects of these compounds on long-term memory.

Catalytic Subunit of PKA as a Prototype of the Eukaryotic Protein Kinase Family

The catalytic subunit of protein kinase A (PKAc) is conserved in all eukaryotic protein kinases. PKAc consists of two lobes that form the catalytic cleft containing the ATP-binding, peptide-binding site, and catalytic sites. During folding, PKAc secondary structures organize so that the non-polar regions form a globular core, while mobile loops and tails are exposed and can act as regulatory elements. De novo synthesized PKAc is phosphorylated at the T-loop, resulting in the formation of the active center capable of high-affinity binding of co-substrates. The ATP-molecule "sticks" the two lobes together, whereas the binding of peptide substrate completes the active center formation. The resulting catalytic triad (γ-phosphate of ATP, hydroxyl of Ser/Thr residue of the protein substrate, and Asp166 carboxyl) occupies a position optimal for catalysis. During the catalytic cycle, dynamic reorganization of polar and hydrophobic interactions ensures PKAc transition from the open to the closed conformation and vice versa. Understanding the structural basis of functioning of eukaryotic protein kinases (ePKs) is essential for successful design of ePK modulators.

Role of orexin peptide system in emotional overeating induced by brain reward stimulation in fed rats

Introduction: The purpose of this work was to prove that the reaction of food self-deprivation in “fed up” rats is a suitable model for studying the emotional overeating in the experiment.

Methods: The self-deprivation reaction, i.e. self-isolation of an animal from food during electrical self-stimulation of the brain, was studied in animals with food deprivation. To reproduce the self-stimulation of the lateral hypothalamus, the male Wistar rats were trained to press a pedal in a Skinner box. After training, the rats received food deprivation, then a feeder was placed in the Skinner box, and a conditioned food reflex was developed in rats within 5 days.

Results and discussion: The food self-deprivation reaction was observed in the ”satiated” rats with a current intensity of 10% and above the threshold for self-stimulation. Hungry animals pressed the pedal for hypothalamic self-stimulation and took no notice of the feeding trough. Sulpiride, a dopamine D2 antagonist (5 and 20 mg/kg i.p.), administered to the “satiated” rats decreased both the eating behavior and self-stimulation in food self-deprivation testing. SB-408124, an orexin A receptor antagonist (0.5 mg/ml, 20 μl intranasally) reduced only the number of pellets eaten, but not the number of pedal presses.

Conclusion: The orexin A receptors are preferably involved in emotional eating compared with orexin B (OX2R TCS-OX2-29) and D2 dopamine receptors. Because emotional eating is significantly related to clinical eating disorders, like bulimia and binge eating disorder, it seems promising to use drugs of the orexin system to treat and prevent the issue.

[Alcoholization and ethanol withdrawal leads to the activation of neuroimmune response in the prefrontal rat brain]

The effects of acute (single) and chronic ethanol administration on the level of pro-inflammatory cytokines (IL-1β and TNF-α), as well as on the level of mRNA NF-κB, TLR4 and its endogenous agonist, HMGB1 protein, were investigated in rats. It was shown that the level of TLR4, HMGB1 and cytokines was significantly higher than in control group. The ethanol withdrawal after prolonged administration resulted in dysregulation of cytokine levels, TLR4 and HMGB1. Changes in the level of TLR4 and HMGB1 mRNA demonstrated a similar pattern. The obtained data confirm that prolonged alcoholization leads to the activation of TLR4-dependent signaling in the prefrontal cortex of rats, and this can lead to a prolonged neuro-inflammatory process in the brain.

Tissue-Specific Peculiarities of Vibration-Induced Hypoxia in Rabbit Liver and Kidney

Activity of the energy production systems in rabbit liver and kidney under conditions of unfavorable vibration exposure was studied by the polarography method using a galvanic-type closed oxygen sensor. The rate of oxidation of endogenous substrates by mitochondria was determined by the tissue and was 5.2±0.6 and 8.13±1.4 (ng-atom O)×min^-1×mg^-1 protein for liver and kidney of intact animals, respectively. After 21 vibration sessions against the background of inhibition of NAD-dependent substrate oxidation in liver mitochondria, the rate metabolism of exogenous succinic acid increased by 44% and then decreased with prolongation of the effect, which indicated impaired function of the respiratory chain. Similar fluctuations of the parameters were revealed in kidney mitochondria, though their amplitude was lower. The study of bioenergetic mechanisms of hypoxia in various tissues makes it possible to determine the targets for the pharmacological action of antihypoxic drugs.

[The time course of changes in the state of monoaminergic systems in the brain of mice under the acute hypoxia with hypercapnia]

In socially isolated male outbred albino mice, the changes of monoaminergic systems under acute hypoxia with hypercapnia were studied. In cerebral cortex, hippocampus and striatum of the right and left sides of the brain, the concentrations of norepinephrine, dopamine, serotonin and their metabolites - dihydroxyphenylacetic, homovanillic and 5-hydroxyindoleacetic acids were investigated using the HPLC method. In isolated mice, which were not subjected to hypoxia with hypercapnia, higher levels of dopamine and serotonin in the left cortex were found. There was no asymmetry in monoamines and their metabolites in other studied brain structures. 10 min after the onset of exposure, acute hypoxia with hypercapnia resulted in a right-sided increase in norepinephrine levels and a decrease in dopamine levels in the striatum and serotonin levels in the hippocampus. In the cerebral cortex, 10 min after of hypoxic exposure beginning, there was a left-sided decrease in the dopamine content, while the original asymmetry found in the cortex of intact animals disappeared. In isolated mice perished of hypoxia with hypercapnia, almost all parameters returned to the control level. The exception was the ratio of serotonin metabolite level to the neurotransmitter, which in the right cortex became lower than in control animals. In white outbred mice, the brain monoaminergic systems are suggested to be relatively resistant to the negative consequences of hypoxia and hypercapnia, and corresponding shifts resulting in the reflex brain response to changes in the gas composition of the respiratory air.

The value of extended amygdala structures in emotive effects of narcogenic with diverse chemical structure

Introduction: Studies on the mechanisms of the reinforcing action of opioid and non-opioid narcotics confirmed the existence in the brain of a specialized system named the extended amygdala.

Materials and methods: To clarify the value of the extended amygdala structures (bed nucleus, central nucleus of the amygdala and nucleus accumbens shell) in the mechanisms of unconditioned and conditioned reinforcement activated by various narcogenic, this paper carried out a neuropharmacological analysis of these effects, using blockade of dopamine receptors, GABA, opioids and CRF receptors within these brain structures, as well as an analysis of behavioral responses by self-stimulation (unconditioned reinforcement) and conditioned place preference (CPP) (conditioned reinforcement).

Results and discussion: The central amygdala and the bed nucleus have a controlling influence on the hypothalamus, which is predominantly of CRF-, GABA- and dopaminergic nature. Through D1 dopamine receptors,, a direct positive (activating) effect on the lateral hypothalamus is made. The D2 receptor blockade of the nucleus accumbens prevents narcogenic from exerting the reinforcing properties, which are primarily stimulating. The blockade of the D1 receptors of the nucleus accumbens by SCH-23390 prevents the expression of unconditioned and conditioned reinforcing properties of predominantly opiates and opioids. The blockade of GABAA receptors in the nucleus accumbens with bicuculline prevents the manifestation of the primary and secondary reinforcing properties (CPP) of psychostimulant drugs (amphetamine), without affecting the effects of opiates and opioids (fentanyl and leu-enkephalin).

Conclusion: The pharmacological analysis proves that CRF, dopamine and GABA receptors are most important for the correction of reinforcement activated by various narcogenic.

[Effects of сramizol on expression of the ApoA1 gene in rats with experimental hyperlipidemia]

An imidazole derivative cramizol, has lipid-lowering and anti-atherogenic effects. Cramizol reduces blood levels of cholesterol and triglycerides, and also reduces the atherogenic index in animals with acute hyperlipidemia induced by Triton WR-1339. Cramizol and the lipid-lowering drug fenofibrate exhibited similar effectiveness as hypolipidemic agents. Cramizol also restores the expression of the Apoa1 gene in rats with experimentally induced hyperlipidemia to normal values. This may be a basis of its hypolipidemic and anti-atherogenic action.

[Ethanol withdrawal leads to an increase in the CRFR2 mRNA level in the ventricular tegmental region of the rat brain]

The neurotransmitter systems of the brain are exposed to dysregulation during alcohol withdrawal. This contributes to the development of the pathological craving for alcohol in which corticotropin-releasing hormone receptors are may be involved. During the period of alcohol withdrawal, the level of CRFR2 mRNA in the ventral tegmental area of the brain on the seventh day of abstinence was significantly increased in comparison with the control group. This supports existing concepts on possible participation in the modulation of dopaminergic and GABA-neural neurons in the ventral tegmental area the brain.

[Chronic alcoholism influences the mRNA level of the orexin receptor type 1 (OX1R) in emotiogenic structures of the rat brain]

Orexin and its receptors were shown to be involved into mechanisms of pathological craving to alcohol. This paper demonstrates that the orexin receptor type 1 (OX1R) mRNA level significantly decreased in the prefrontal cortex of rats chronically (during 6 months) consuming ethanol compared with intact control. The same results were observed on day 1 and day 7 of alcohol withdrawal after chronic alcoholization. On the contrary, in the hippocampus, the OX1R mRNA level increased on day 1 and day 7 of alcohol withdrawal. In the ventral tegmental area, the OX1R mRNA level did not change on the day 1 and day 7 of alcohol withdrawal compared with the groups of chronic alcoholization and intact control. These findings point out involvement of the prefrontal cortex and hippocampus first of all in mechanisms mediating chronic alcohol intoxication. The ventral tegmental area is described as a typical dopaminergic structure providing the executive mechanism of emotion reactions connected with alcohol abuse in particular. It is possibe, that the modulating action of orexins on dopaminergic neurons in this structure does not provide a significant effect on control of emotion reactions in alcoholism.

[Central monoaminergic systems sensitivity to acute hypoxia with hypercapnia changes after the maintenance under the long-term social isolation]

The experiments were performed in male albino outbred mice kept in a group and under the conditions of long-term social isolation. The changes in the monoaminergic systems of the left and right hemispheres of the brain after acute hypoxia with hypercapnia have been studied. The levels of dopamine (DA), serotonin (5-HT) and their metabolites - dioxyphenylacetic (DOPAC), homovanillic (HVA), and 5-hydroxyindoleacetic (5-HIAA) acids - were determined by HPLC in the cerebral cortex, hippocampus and striatum of the right and left sides of the brain. In the control mice kept both in the group and under the conditions of social isolation, a higher content of DA in the cortex of the left hemisphere has been found. In the other brain structures the monoamine content was symmetric. In the cerebral cortex of the mice in the group, acute hypoxia with hypercapnia led to a right-sided increase in the DA and 5HT levels. At the same time, the DOPAC content decreased in the left cortex. In mice in the group, under the hypoxia with hypercapnia conditions, the DA level in the left hippocampus increased. In the striatum, the content of monoamines and their metabolites did not change significantly. In animals kept for a long time under the conditions of social isolation, hypoxia with hypercapnia no statistically significant changes in the monoamines and their metabolites levels were found. It has been concluded that the preliminary maintenance under the conditions of prolonged social isolation changes the reaction of central monoaminergic systems to acute hypoxia with hypercapnia.

[The effect of acute hypoxia with hypercapnia on the content of monoamines in symmetrical areas of the brain in albino mice]

Changes in the activity of monoaminergic systems of the left and right hemispheres of the brain after acute hypoxia with hypercapnia were investigated in male albino mice. The concentrations of dopamine (DA), serotonin (5-HT) and their metabolites dihydroxyphenylacetic (DOPAC), homovanilic (HVA) and 5-hydroxyindolacetic (5-HIAA) acids were measured by HPLC in the brain cortex, hippocampus and striatum of the right and the left hemispheres. In the control mice not exposed to hypoxia with hypercapnia, a higher concentration of DA in the left cortex was detected. No asymmetry in the content of other substances has been identified in the investigated structures. Acute hypoxia with hypercapnia led to the right-sided increase of DA and 5-HT levels and to the left-sided reduction DOPAC in the cerebral cortex. Under the condition of hypoxia with hypercapnia, in the hippocampus, the left-sided increase of the DA content was revealed. In the striatum the contents of monoamines and their metabolites were insignificantly changed. It has been concluded that acute hypoxia with hypercapnia causes asymmetric changes in monoaminergic systems of the archicortex and the neocortex.

System of KISS-KISS1R: focus on peripheral signaling in androgen-dependent tissues in the experimentally induced model hypogonadotropic hypogonadism

Kisspeptins, ligands of G protein-coupled receptor 54 (GPR54) encoded by the KiSS-1 gene, have recently emerged as key gatekeepers of the gonadotropic axis. Unlike its role at the hypothalamus on GnRH secretion, the effects of kisspeptins on gonadal and other peripheral tissues need to be clarified.

THE PURPOSE

To investigate the impact of experimentally induced hypogonadism in male rats on kisspeptins signaling in androgen-dependent tissues and blood.

METHODS

Wistar male rats (total number 31) were used. Rats were divided into four groups. Group 1 (control, prepubertal rats aged 2 months, n = 7). Group 2 (control, pubertal rats aged 4 months, n = 6). Group 3 (unilaterally gonadectomized (ULG) in neonatal period). Group 4 (ULG testosterone-treated with testosterone (T) propionate 5 mg/kg/d during 10 days). In all the four groups density of GPR54 in testes and muscle and serum kisspeptin levels and T levels were estimated. The data was expressed as median values (Me) that were compared by Wilkokson criterion.

RESULTS

Density of GPR54 in gonads in group 3 was lower than in group 2 (Me 0,88 ng/mg vs 1,13 ng/mg, p<0,05) and similar to group 1(Me 0,92 ng/mg). Unlike above, density of GPR54 in muscle in all groups 1,2,3 was not any differences (Me 0,1; 0,12; 0,13 ng/mg, p>0,05).Generally, density of GPR54 in group 2 in gonads was significantly higher than in the same group in muscle (Me 0,784 ng/mg vs 0.114 ng/mg, p<0,01). In the group 3 a significant decrease in serum levels of T (Me 15,39 ng/mg) in comparison with group 2 (Me 20,02 ng/mg, p<0,01) was invented. However, serum levels of kisspeptins in both groups had not any differences (0,27 ng/mg and 0,26 ng/mg, p>0,05). Treatment with testosterone propionate of the rats of group 4 lead to increase of serum level of T (from 15,39 ng/mg to 26,26 ng/mg, p<0,01), but didn`t modify the density of GPR54 in gonads (Me 0,79 ng/mg).

CONCLUSIONS

Hypogonadism lead to decrease of kisspeptins signaling in peripheral androgen-dependent tissues. Serum level of kisspeptins is physiologically low and, probably, it can not be used as a marker of activity of kisspeptins system. Efficacy of treatment with testosterone is not enough that is required a novel therapeutic resources.

Antioxidant Effect of Polyoxidonium and Metaprot during Bronchopulmonary Inflammation in Rats

The antioxidant effects of individual or combined application of polyoxidonium and metaprot were examined in rats with acute bronchopulmonary inflammation. By degree of antioxidant potency, polyoxidonium was inferior to metaprot, but their combined application produced more potent antioxidant effect. Polyoxidonium and metaprot in low concentrations increased and in high concentrations suppressed spontaneous biochemiluminescence in the model system of alveolar macrophages.

[Analysis of tropalgin effects in an inflammation pain model in rats with different pain threshold]

Individual pain sensitivity of male Wistar rats was determined in a tail-flick model after action of focused thermal ray (flick) on tail. Rats with latency less than 5 sec were qualified as high sensitive (HS) to pain, more than 10 sec as low sensitive (LS) to pain. Effects of a new nonopioid analgetic tropalgin 2 mg/kg (ED50) i.p. was studied in both groups of rats. Tropalgin was effective as an analgetic in aseptic inflammation model (formaldehyde test). The analgetic effects of tropalgin were same as after administration of methamizol sodium (50 mg/kg) or diclofenac sodium (7 mg/kg). Tropalgin did not change individual pain sensitivity in both HS and LS rats without inflammation. In HS to pain rats, the common time of pain behavioral reactions was decreased by 53% in an acute phase of pain and by 58% in a tonic phase of pain in inflammation pain model. In LS to pain rats, the time of leaking of inflamed paw was decreased by 42% in the first phase and by 66% in the second phase. We suggest that analgetic effect of tropalgin is connected with adenosine release in purinergic neurons that has been demonstrated earlier for drugs of tropin structure.

[Effect of galantamine and testosterone on the arthritic response and dopamine content in rat spleen]

The study was carried out on male Wistar rats with surgically ablated gonads. The rats with gonadectomy and intact rats received galantamine and/or testosterone over 10 days, after which the model arthritis was induced by injection of 200 ml of complete Freund's adjuvant. It was established that gonadectomy reduced arthritic reactions producing ulcer formation at a later time (21 days) as compared to control (rats with arthritis), where they are formed on the local stage of development (day 7). Testosterone replacement therapy completely blocks the development of ulcers on the paws. Galantamine suppresses the arthritic reaction more significantly, reducing paws and ankle-joint edema 1.5 and 1.3 times respectively (n = 12, p <0.05). The appearance of dopamine in the spleen during galantamine treatment may serve as a marker of protective action of the drug under hypoandrogenic conditions. Introduction of galantamine at high level of testosterone does not significantly influence on development of arthritic reaction, which is indicative of a marked imbalance between the hormonal and cholinergic systems and a possibility to modulate arthritic reaction with cholinergic drugs.

[Thermal homeostasis of the rabbit in thermoneutral zone (mathematic modeling)]

The thermal homeostasis of rabbits in thermoneutral zone were studied in the paper. Both in the experiment and in the model were shown that the temperature in the shell of the animal was changed without changing the core (nuclear) temperature when the temperature of the environment was changed and the heat production and delivery were remained unchanging. In the model was obtained this phenomenon was due to changing the shell and the core values, and was connected with blood flow variations in the shell. The latter mechanism was assessed as a principal one for active and quick regulation of the organism temperature and support of constant core temperature without significant and energy consumed is changing the heat production and delivery in thermoneutral zone of the mammalians. So, the thermoneutral zone is supported by the mechanism described, and the value of the thermoneutral zone is due to the shell size.

Effect of amtizol on resistance of SHR mice to acute hypoxia with hypercapnia under conditions of isolated functioning of one cerebral hemisphere

Antihypoxant amtizol (25 mg/kg) prolonged the lifespan of intact SHR mice by 46.2% under conditions of isolated functioning of one cerebral hemisphere. The effect of amtizol on sham-operated animals was less pronounced: the lifespan of mice was prolonged by just 28.1%. Injection of amtizol to mice with active right hemisphere significantly prolonged the lifespan of experimental animals (by 64.8%). The drug was ineffective under conditions of active left hemisphere: the result coincided with the lifespan of similar mice without the drug injection. Hence, antihypoxic effect of amtizol was largely determined by its effect on the right, but not the left cerebral hemisphere.

[Reactive changes of the rat brain cellular elements under different conditions of circulatory hypoxia]

The aim of this study was to detect structural, spatial and quantitative changes of cellular elements of midbrain paranigral nucleus (PNN) and telencephalic anterior cingulate area (ACA) under different conditions of circulatory hypoxia. PNN anteriormedial part and ACA layers V-VI were examined in adult rats 7 days (n=4) after an occlusion of both common carotid arteries as well as in intact (1st control, n=4) and sham-operated animals (2nd control, n=4). In histological the sections, stained with Nissl cresyl violet, and using the methods of glial fibrillary acidic protein and an Ibal-protein detection, the proportions of unmodified, hypochromic, pyknomorphic neurons and ghost cells were determined as well as the numbers of astrocytes, oligodendrocytes, microgliocytes and endotheliocytes. Cell body area of neurons and gliocytes, and the distance between cell bodies and capillaries were measured, a gliocyte-neuronal index was calculated. It was found that brain cellular elements that survive different conditions of a circulatory hypoxia underwent a range of pathological changes. Neurons were in process of nuclear pyknosis, lysis and transformation into the ghost cells. The cells within the hypoxia nuclear zone were prone to death or pyknosis. The neurons located outside the area of hypoxia which were affected only by a humoral impact of reactions of the glutamate-calcium cascade, frequently underwent acute swelling. Microgliocyte reaction in the form of poorly expressed increase in their number and structural signs of activation was an early diffuse manifestation of a prosencephalic focal hypoxia. Endotheliocyte proliferation 7 days after of ischemic challenge was not associated with a chain of cascade reactions and was observed only in the hypoxia focus. Concentration of viable neurons and astrocytes near blood capillaries, as well as an increase in the number of satellite form gliocytes is an adaptation mechanism and a condition for the survival of cells during various types of brain exposure to ischemia.

[Experimental substantiation for the application of calcium channel blockers in vibration disease]

The mechanism of vibroprotective action for nifedipine, a calcium channel blocker, was studied in myocardiocytes of rabbits. The shifts in functional activity of mitochondria were registered after prolonged common vibration of rabbits during 56 days (1 h every day). Nifedipine (7.5 mg/kg per os) activated NAD-depended site of respiratory chain and prevented hyperactivation of succunate-depended breath. The positive energotropic action of nifedipine was accompanied by stability of histomorphological cytoarchitechture of rabbit myocardium, wich was disturbed in nontreated animals. It is suggested that nifedipine protects myocardium from prolonged action of vibration.

[The effect of ethanol exposure in pregnancy on maturation of monoaminergic systems in the developing rat bran]

Simultaneous study of the main neurotransmitter of monoaminergic system of the brain, its metabolites, activity of catechol-O-methyltransferase (COMT) and the state of different subtypes of dopamine (DA) receptors in the developing brain of offspring from mothers alcoholized in gestation and feeding periods revealed a decrease in activity of all monoaminergic systems studied with reduction of noradrenaline and DA level in alcoholized fetus as well as of mPNA of COMT, an enzyme of catecholamine metabolism, in the structures of the forebrain on the 17th day but not on 13th day of prenatal development. In parallel experiments, an increase of the contents of both long and short splice variants of D2 DA receptor was registered. In postnatal period (days 4, 10, 17), further decrease of the DA system activity was observed, particularly a reduction of DOPAC level and DOPAC/DA ratio in rat litter, mothers of whom took alcohol in the gestation period with withdrawal it after birth of offspring. The serotonin system activity was also reduced in alcoholized litter in the postnatal period and was registered in the early stages (on the 4th day of life). Therefore, the serotonin system activity is changing at early stages of development (the 4th day), whereas inhibition of the DA system activity is registered at later stages (the 10th day of life).

[Stressogenic exposure of local vibration to energetic metabolism of the heart, liver and kidney of rats]

The purpose of the paper was to study the activity of energy producing system of the rabbit myocardium, liver and kidneys after exposure to local vibration during 7 days. The energy dependent reactions of native mitochondria were investigated by means of polarographic method using dark closed membrane electrode. The intensivity ofoxydative processes was assessed according to activity of the lymphocyte succinate dehydrogenase and catalase of the blood. The energy producing system of the tissues studied was shown to be involved in response reaction of the organism on vibration exposure. In that case we observed the formation of the second phase ofbioenergy hypoxia in the myocardium and kidneys and the first phase ofhypoxia in the liver.

[Significance of pain sensitivity for the resistance to immobilization stress]

The effects of immobilization stress (immobilization on back within 4 h) on the functional indexes of Wistar male rats differing with pain sensitivity in the tail-flick test were studied. The acute immobilization stress in rats with high pain sensitivity compared with low pain sensitivity animals produced the most changes of the main functional systems. The high pain sensitivity rats demonstrated more significant hypotension, bradicardia, temperature shift, decrease of breath frequency and oxygen consumption, acid-alkaline equilibrium disorders with lactate acidosis signs. Therefore, the rats with low pain sensitivity possess the high resistance to acute stress exposure in comparison with high pain sensitivity animals. This confirms the important significance of individual pain sensitivity for the formation of stress resistance.

[Protective effects of metaprot and ethomerzol in carbophos intoxications]

The mechanisms of protective action of thiobenzimidazole derivatives metaprot and ethomerzol (25 and 50 mg/kg) have been studied on a model of carbophos intoxication (256.0 +/- 8.7 mg/kg) in rats. Both compounds recovered the resistance to physical loads in forced swimming test, normalized the activity of aspartate and alanine transaminases, and reduced bilirubin, creatinine, and urea nitrogen levels in the blood serum. The intoxication was accompanied with increasing concentration of malonic dialdehyde and decreasing level of recovered glutation in the blood, as well as with the signs of endogenic intoxication. Metaprot and ethomerzol diminished disorders of both the lipid peroxidation and endogenic intoxication processes. Thus, the antihypoxic, antioxidant, actoprotective, energotropic, and reparative effects of metaprot and ethomerzol have been proved. Ethomerzol was more effective than metaprot in these tests.

[Participation of GABA- and dopaminergic mechanisms of the bed nucleus of stria terminalis in reinforcing effects of psychotropic drugs mediated via the lateral hypothalamus]

The purpose of the investigation was to elucidate significance of GABA and dopamine systems of the bed nucleus of stria terminalis for the reinforcing effects of a number of psychotropic drugs (opiates, opioids, psychostimulants) on self-stimulation of the lateral hypothalamus in rats. To the Wistar male rats, bipolar electrodes were implanted in the lateral hypothalamus to study self-stimulation reaction in the Skinner box. Simultaneously, the microcannules were implanted into the bed nucleus of stria terminalis to inject the drugs under study. Some drugs, xycaine, or lidocain, a blocker of sodium influx ionic currents, antagonists of GABAA receptors bicuculline, D1 dopamine receptors SCH23390 and D2 dopamine receptors sulpiride which were administered intrastructurally into the bed nucleus of stria terminalis, were used for pharmacological analysis. Xycaine > SCH23390 = bicuculline inhibited self-stimulation of the lateral hypothalamus. The reinforcing properties of a number of psychoactive drugs (amphetamine, Fentanyl, sodium ethaminal and leuenkephaline) were changed on the background of their action. It is concluded that the bed nucleus of stria terminalis controls the hypothalamic self-stimulation via GABA- and dopaminergic mechanisms. GABA realizes the negative (inhibitory) action. The direct positive (activating) effect on the lateral hypothalamus is realized through D1 dopamine receptors, and D2 dopamine receptors of the bed nucleus of stria terminalis limit the positive effects of narcogenic drugs.

Comparative efficiency of succinate-containing antihypoxants in traumatic toxicosis

Experiments on Wistar rats showed the development of endotoxicosis 12 h after severe compression injury. Endotoxicosis manifested in disorders in bromosulfaleine excretion from the blood, increase of blood urea, uric acid, creatinine, and potassium levels and aminotransferase activities. Injection of succinate-containing antihypoxants (reamberine, cytoflavin, metaprot plus, succinamic acid 2-amino-4-acetylthiasolo[5,4-b]indole) directly after decompression promoted recovery of liver function, prevented the development of hyperfermentemia and renal failure as a result of reduced blood levels of potassium and non-protein nitrogen. The protective effect of the drugs in traumatic toxicosisdecreased in the following order: metaprot plus>cytoflavin>2-amino-4-acetylthiasolo[5,4-b]indole succinaminic acid>reamberine.

[The extended amygdala system and self-stimulation of the lateral hypothalamus in rats: modulation with opiates and opioids]

Wistar male rats were implanted with bipolar electrodes in the lateral hypothalamus to study self-stimulation reaction in the Skinner box. Simultaneously, the microcanules were implanted into the central nucleus of the amygdala to inject the drugs studied (1 microl in volume for each injection). The blockade of CRF receptors (astressin 1 microg) or sodium influx ionic currents (xycaine, or lidocain 1 microg) by means of intrastructural administration of drugs into the amygdala descreased self-stimulation reaction of the lateral hypothalamus in rats by 29-55%. The inhibition of D2 and D2 dopamine receptors in the amygdala with SCH23390 (1 microg) or sulpiride (1 microg), respectively. reduced self-stimulation too, but in less degree. On the background of blockade of CRF (astressin) and dopamine (sulpiride) receptors, as well as sodium influx ionic currents (lidocain) in the amygdala neurons, psychomotor stimulant amphetamine (1 mg/kg) and barbiturate sodium ethaminal (5 mg/kg) supported their psychoactivating effect on self-stimulation (+30-37%), but fentanyl (0.1 mg/kg) had got no effect. Fentanyl activated self-stimulation moderately only after blockade D1 dopamine receptors with SCH23390. After blockade of CRF receptors, leu-enkephaline strengthened its depressant effect on self-stimulation reaction (-89%). Therefore, if the modulating influence of the amygdala on the hypothalamus is diminished, the reinforcing effects of opiated (fentanyl) and opioids (leuencephaline) will block, but there will be no effect for psychomotor stimulant amphetamine and barbiturate sodium ethaminal.

[Behavioral correlations of gradual forced administration of psychoactive drugs]

The study was aimed at evaluating the behavioral correlations of the forced administration of psychoactive drugs. Wistar rats received the following drugs in elevated doses (over 4 days, i. p.): (i) physiological saline (control; 0.1-0.2-0.4-0.8 ml/rat), (ii) psychostimulant amphetamine (0.5-1.0--2.0-4.0 mg/kg); (iii) opioid analgetic fentanyl (0.00625-0.0125--0.025-0.05 mg/kg), (iv) ethanol 40% solution (0.5-1.0--2.0-4.0 g/kg), (v) barbiturate sodium ethaminal (2.5-5--10-20 mg/kg); and(vi) synthetic glucocorticoid dexamethasone (0.5-1.0--2.0-4.0 mg/kg). The forced regime of drug administration led to gradual load of the organism and prevented drug tolerance. The dynamics of self-stimulation reaction of the lateral hypothalamus was registered every day over drug administration period and revealed the following regularities: (I) dose-dependent effect of psychostimulant amphetamine and opioid analgetic fentanyl; (II) dexamethasone modulated self-stimulation, increasing (2 day, 1 mg/kg) or decreasing it (3 day, 2 mg/kg); (III) ethanol (1-2 g/kg) activated self-stimulation slightly; (IV) sodium ethaminal slightly inhibited self-stimulation and increased the thresholds of self-stimulation. In 24 h and 72 h after the last administration of drugs, the rat behavior was assessed in open field, elevated plus maze, resident-intruder paradigm, and Porsolt's test. In the open field, significant signs of post-intoxication exposure of psychoactive drugs were revealed, which were registered for 24-72 h after drug withdrawal. The withdrawal of drugs was accompanied with reduction (in 24 h) and subsequent recovery (in 72 h) of the vertical motor activity, exploration behavior, and emotionality. The anxiety indexes were increased up to the 3rd day after withdrawal. The antidepressant effect was also increased. The system of aggression-defense was restored only in rats treated with ethanol. The indexes of individual behavior and communicability in the post-intoxication period were decreased as well. It is suggested that the forced regime of drug administration in increasing doses with subsequent withdrawal of drug injections is a suitable method to evaluate the behavioral elements of drug dependence.

[Hepatoprotective properties of cytochrome C in traumatic toxicosis]

Experiments on rats showed that traumatic toxicosis (crush syndrome) was accompanied by disorders of both excretion and detoxication functions of the liver and a decrease in the energy potential of the liver. Systemic administration of cytochrome C (10 mg/kg) immediately after trauma and decompression increased the level of endogenous cytochrome C, recovered the pool of adenine nucleotides, normalized bromsulfaleine excretion from the blood, and decreased the content of toxic metabolites in the blood. The obtained experimental data show that cytochrome C possesses high hepatoprotective properties with respect to the development of traumatic toxicosis.

[Cortexin and cortagen as correcting agents in functional and metabolic disorders in the brain in chronic ischemia]

The polypeptide drug cortexin and the synthetic peptide drug cortagen accelerate the recovery of disturbed individual behavior of ischemic rats with different resistance to hypoxia (high and low resistant rats). In addition, both drugs prevented an excessive activation of lipid peroxidation and a decrease in the antioxidant activity in the brain tissues. The obtained results suggest that cortexin and cortagen can be used for increasing the efficacy of neuroprotective therapy in cases of chronic brain ischemia.

[Significance of CRF and dopamine receptors in amygdala for reinforcing effects of opiates and opioids on self-stimulation of lateral hypothalamus in rats]

Bipolar electrodes were implanted in the lateral hypothalamus in a group of 44 Wistar male rats in order to study self-stimulation reaction in the Skinner box. Simultaneously, microcanules were implanted into the central nucleus of the amygdala to inject the drugs (1 microl per injection). The blockade of corticoliberin (CRF) receptors (astressin, 1 microg) or Na+influx currents (xycaine or lidocain 1 microg) by the intrastructural administration of drugs into the amygdala decreased self-stimulation reaction of the lateral hypothalamus in rats by 29-55%. The inhibition of D1 and D2 dopamine receptors in the amygdala with SCH23390 (1 microg) or sulpiride (1 microg) respectively, also reduced self-stimulation but to a lower degree. On the background of blockade of CRF (astressin) and dopamine (sulpiride) receptors as well as sodium influx ionic currents (lidocain) in the amygdala neurons, psychomotor stimulant amphetamine (1 mg/kg) and barbiturate sodium ethaminal (5 mg/kg) retained their psychoactivating effect on self-stimulation (+30-37%), while fentanyl (0.1 mg/kg) and leu-enkephaline (0.1 mg/kg) did not produce this effect. Fentanyl moderately activated self-stimulation only after the blockade of D1 dopamine receptors with SCH23390. After the blockade of CRF receptors, leu-enkephaline strengthened its depressant effect on self-stimulation reaction (-89%). Therefore, if the modulating action of amygdala on the hypothalamus is eliminated, the enhancing effects of opiates (fentanyl) and opioids (leu-encephaline) are blocked, but the effects of psychomotor stimulant amphetamine and barbiturate sodium ethaminal are retained.