Effect of RGPU-260, a Novel GABA Derivative, on Functional Reserves of Rat Heart after Chronic Alcohol Intoxication.

The effect of a new derivative of GABA, the compound RGPU-260, on the heart contractility of rats exposed to chronic alcohol intoxication (10% ethanol solution for 24 weeks) was studied. In comparison with intact rats, the alcoholized ones were characterized with smaller increments in the rates of myocardial contraction (+dP/dtmax) and relaxation (-dP/dtmax), left ventricular pressure, and maximum intensity of functioning of structures during the load tests (volume load/preload, stimulation of the cardiac adrenergic receptors, and occlusion of the ascending aorta/afterload) attesting to degraded cardiac contractility function. In rats treated with RGPU-260 (daily, 25 mg/kg intragastrically during 14 days), these parameters were higher in comparison with control values indicating a positive action of the examined agent on inotropic function of the heart. Effectiveness of cardiotropic action of RGPU-260 was comparable to that of the reference drug mildronate.

Peculiarities of the Expression of Inducible NO Synthase in Rat Dentate Gyrus in Depression Modeling.

Mild stress exposure contributes to the development of cognitive and emotional deficits, is considered as a model of depressive state, and is characterized by enhanced NO production. In albino mature (12-month-old) male rats, the depressive state was simulated by daily 30-min exposure to stressful stimuli (vibration, loud sound, and strobe light) over 7 days in a special chamber. On paraffin frontal sections of the brain stained with antibodies against inducible NO synthase (iNOS), the expression and distribution pattern of immunoreactive material were evaluated in various layers of the dentate gyrus under normal conditions and after depression modeling. The relative area of iNOS expression in the dentate gyrus of control rats was 8.2 (7.1-9.9)%, while in rats with experimental depression, this parameter was 16.7 (10.5-22.1)%, i.e. increased by 8.5% (p<0.05). In mature rats with modeled depressive state, the expression and relative area of iNOS expression in neuronal perikarya in the granular and subgranular layers of the dentate gyrus increased, which can underlie the mechanisms of damage and determine reduced neuroplasticity and suppressed neurogenesis in the dentate gyrus in rats during adulthood.

Correction of Alcohol-Induced Damage to Mitochondria in Cardiac and Cerebral Cells by Derivatives of Neuroactive Amino Acids.

We studied LPO intensity and respiration of mitochondria in brain and heart cells of rats receiving 5% ethanol for 20 weeks and treated with derivatives of neuroactive amino acids. Chronic semicompulsory alcohol intoxication increased the concentration of LPO products in cardiac and cerebral mitochondria by 46 and 45% (diene conjugates), by 97 and 8% (diketones), and by 28 and 81% (malondialdehyde), respectively, reduced activity of antioxidant enzymes in cardiac and cerebral mitochondria by 24 and 45% (glutathione peroxidase) and by 22 and 26% (superoxide dismutase), respectively, and uncoupled the process of respiration and ATP synthesis, which manifested in a decrease in respiratory control (V3/V4 ratio according to Chance). Glutamic acid derivative Neuroglutam (26 mg/kg) and GABA derivative succicard (44 mg/kg) administered intraperitoneally daily for 28 days after termination of alcoholization decreased the levels of primary and secondary LPO products, up-regulated activity of antioxidant enzymes in mitochondria of the heart and brain, and moderated the mitochondrial dysfunction.

Effects of Gaba Derivatives on Anxious and Compulsive Behavior in Offspring of Rats with Experimental Preeclampsia.

We studied the effects of GABA derivatives on anxious and compulsive behavior of progeny of rats with experimental preeclampsia provoked by replacement of drinking water for 1.8% NaCl solution from the first day of pregnancy to delivery. In comparison with progeny of health rats, the offspring of dams with complicated pregnancy demonstrated high level of anxiety and the development of obsessive-compulsive disorder both at the early (40 and 70 days) and late (6 and 12 months) stages of ontogeny. GABA derivatives succicard, salifen, and phenibut reduced symptoms of experimental preeclampsia in offspring of various age by decreasing the level of anxiety and reducing compulsive behavior. The efficacy of the examined derivatives was similar to that of the reference drug Pantogam.

[Age-specific changes in the functional indices of rats' cardiac mitochondria in chronic alcohol intoxication.]

The effect of chromic continuous consumption of 5 and 10% ethyl alcohol over 6 months on the respiratory function and oxidant/antioxidant status of rats' cardiac mitochondria of different gender and age has been studied. A decrease in oxygen consumption rate by cardiomyocyte mitochondria in the metabolic conditions V2, V3, V4 according to Chance involving activation of respiratory chain complexes I, I+II and II in elderly (24-month old) animals as compared to young (11-month old) animals. As the rats were ageing, the concentration of lipid peroxidation (LPO) products (malondialdehyde) was increasing, while the activity of antioxidant enzymes (superoxide dismutase and glutathione peroxidase) was decreasing in cardiomyocyte mitochondria. Chronic alcoholization of 24-month old rats of both genders resulted in a more pronounced decline in the respiratory function activity of cardiac mitochondria, uncoupling of respiration and oxidative phosporylation, reduced activity of antiradical protection enzymes and increased LPO products as compared to younger rats.

Expression of Beclin-1 and LAMP-2 in Rat Hippocampus under Conditions of Simulated Gravity Overload in the Caudocranial Vector.

Structural changes in the rat hippocampus in response to chronic cerebrovascular disorders induced by gravity exposure in the caudocranial vector were studied. Qualitative and quantitative morphological analysis detected significant cytoarchitectonic changes in the pyramidal layer: spongiosis, manifest pericellular and perivascular edema, and a drastic increase in the counts of pyramidal neurons with signs of impairment in all hippocampal zones. The density of perikarya in the pyramidal layer decreased. Immunohistochemical study detected high expression of Beclin-1 in CA1 field. High expression of LAMP-2 was detected in CA4 field. Field CA2 was characterized by the maximum counts of damaged cells and high expression of Beclin-1 and LAMP-2.

Evaluation of DNA Damage in Experimental Preeclampsia by Comet Assay.

Experimental preeclampsia induced by substitution of drinking water with 1.8% NaCl during pregnancy was associated with an increase in the level of DNA damage in fetal brain and placenta measured by DNA comet assay by 35.7 and 27.8 times, respectively, in comparison with physiological pregnancy.

Inhibition of the Expression of Inducible NO Synthase by Neuroactive Amino Acid Derivatives Phenibut and Glufimet In Vitro and Ex Vivo.

The effects of glufimet and phenibut (glutamic acid and GABA derivatives, respectively) on concentration of inducible NO synthase and cGMP in LPS-activated mouse peritoneal macrophages and on NO end products in their culture medium were examined in vitro and ex vivo. Addition of LPS into culture medium elevated concentration of NO metabolites in this medium and increased concentration of inducible NO synthase and cGMP in the lysates of peritoneal macrophages, whereas incubation of the cells with examined agents applied at concentration of 10-5 M diminished these indices. Similar results were obtained with intraperitoneal injection of LPS, glufimet, and phenibut. In culture medium containing peritoneal macrophages from the mice injected with LPS (100 µg/kg), the concentrations of inducible NO synthase and cGMP as well as the total concentration of nitrite and nitrate ions increased, whereas in culture medium with the cells from LPS-exposed mice treated with glufimet (28.7 mg/kg) and phenibut (50 mg/kg) these indices significantly decreased.

Effect of Phenibut and Glufimet, a Novel Glutamic Acid Derivative, on Respiration of Heart and Brain Mitochondria from Animals Exposed to Stress against the Background of Inducible NO-Synthase Blockade.

Increased oxygen consumption by heart and brain mitochondria in the absence of ADP and reduced mitochondrial respiration in the presence of ADP were observed in rats exposed to stress simulated by suspension by the dorsal neck skin fold for 24 h, which attests to uncoupling of substrate oxidation and ATP synthesis and can cause electron drain from the respiratory chain, formation of ROS, and oxidative damage to cell structures. Blockade of inducible NO synthase with aminoguanidine (single intraperitoneal dose of 50 mg/kg before stress exposure) increased coupling of respiration and oxidative phosphorylation in heart and brain mitochondria of rats exposed to immobilization-painful stress, which was especially pronounced in cardiomyocytes. The test compounds glufimet (single intraperitoneal dose of 29 mg/kg before stress exposure) and phenibut (single intraperitoneal dose of 50 mg/kg before stress exposure) limited stress-induced mitochondrial damage against the background of inducible NO synthase blockade and without it, which was seen from increased respiratory control ratio in comparison with that in untreated rats exposed to stress (control).

[LONG-TERM EFFECTS OF EXPOSURE TO PERINATAL HYPOXIA ON MICROVASCULAR ENDOTHELIUM OF NEOCORTEX IN RATS].

Morphological characteristics of the elements of vessel walls in the microvasculature of rat neocortex were studied after perinatal hypoxia and subsequent introduction of salifen, a derivative of GABA, at long-term postnatal periods. It is shown that salifen at a therapeutic dose has a protective effect on the endothelium of blood vessels in the microvasculature of neocortex. It is found that after exposure to hypoxia followed by application of salifen no endothelial hypertrophy, appearance of numerous processes of endotheliocytes in the vascular lumen, and narrowing of the capillary lumen occur. The formation of la- mina densa is almost identical to that in the control. Swelling of perivascular astrocytes and reactive chan- ges of pericytes are also absent. In all layers of the neocortex the density of vessel distribution in the mic- rovasculature as well as their cross-sectional area in adult animals of the control group and after exposure to hypoxia and salifen application were approximately identical. It is shown that changes and restructu- ring of the capillary bed after exposure to hypoxia and application of salifen take place at earlier terms of development whereas by the maturity period stabilization of the structural parameters of the microvas- culature occurs. The protective effect of salifen on the elements of capillary walls determines the clinical effectiveness of its use and serves as a basis for further research in this direction.

[Cardioprotective effect of the new derivative of glutamic acid - glufimet in acute immobilization-painful stress in animals of different ages].

The effect of the 24-hour immobilization-painful stress on myocardial contractility of young (6-month), middle-aged (12-month) and old (24-month) female rats was studied. It was identified a reduction of the functional reserve of the heart, which showed a smaller growth rates of contraction and relaxation of the myocardium (+ dP/dt max and -dP/dt max), left ventricular pressure (LVP) and the maximum intensity of the functioning of the structures (MIFS) under increased pre- afterload and adrenergic stimulation of the heart, especially pronounced in the group of 24-month old rats. The animals of all ages treated before and after stressing glufimet in a dose 29 mg/kg, have higher rates of growth + dP/dt max, -dP/dt max, LVP and MIFS during load tests, most significant rates of growth are noticed in older rats compared with the young and middle-aged. Phenibut improves studied parameters equally at 6, 12 and 24-month old females, subjected to stress.

[COMPARATIVE MORPHOFUNCTIONAL CHARACTERISTICS OF ADULT AND OLD RAT VENTRAL HIPPOCAMPUS TO COMBINED STRESS INFLUENCE].

Animals were subjected to seven days combined stress in a special chamber (6 isolated compartments of equal area) with removable multi-modal stressors (noise, vibration, pulsating bright light) every 5 minutes on the stochastic scheme with restraint and temperature rise in the chamber during 30-minute stressing time sessions. After exposure to combined stress in the ventral hippocampus of old rats (24 months) compared with adult animals (12 months) following changes were revealed: marked dystrophic changes and increased inducible nitric oxide synthase expression in pyramidal neurons of CA3 field, signs of impaired hemodynamic disorders in the microvasculature, perivascular edema, decreased endothelial nitric oxide synthase expression in microvascular endothelial cells, as well as decreased expression of serine racemase in the neuropil of the radial layer of CA1 field.

Comparison of the Efficiency of Adeprophen and Antidepressants of Various Groups on the Model of Reserpine-Induced Depression in Rats.

A new (aryloxyalkyl)adenine derivative Adeprophen (9-[2-(4-isopropylphenoxy)ethyl]adenine, VMA-99-82) has a strong antidepressant effect on the model of reserpine-induced depression in rats (single dose 4 mg/kg, intraperitoneally). This effect manifested in suppression of depression-like behavior in the Porsolt forced swimming test (shortening of immobility time and increase in immobility latency, number of jumping episodes, and time of active swimming) and sucrose consumption/preference test (increase in the consumption of 20% sucrose solution in g/100 g body weight and percentage of sucrose preference in relation to the total fluid preference). Adeprophen had a greater antidepressant effect than sertraline and fluoxetine, but was less potent than amitriptyline, imipramine, venlafaxine, and to a lesser extent to paroxetine.

Spatial Memory in the Progeny of Rats Subjected to Different Types of Experimental Preeclampsia.

Spatial memory was studied in 2-month-old offspring of rats subjected to different types of experimental preeclampsia (replacement of drinking water with 1.8% NaCl from day 1 to 21 of gestation or intraperitoneal administration of non-selective NO-synthase inhibitor L-NAME to pregnant rats in a daily dose of 25 mg/kg for 7 days on gestation days 14-20). Spatial memory was evaluated in an elevated 8-arm radial maze. Both types of experimental preeclampsia impaired spatial (long-term and short-term) memory and can be used in the development of drugs correcting negative effects of this pregnancy complication on memory.

Comparison of Nootropic and Neuroprotective Features of Aryl-Substituted Analogs of Gamma-Aminobutyric Acid.

GABA analogs containing phenyl (phenibut) or para-chlorophenyl (baclofen) substituents demonstrated nootropic activity in a dose of 20 mg/kg: they improved passive avoidance conditioning, decelerated its natural extinction, and exerted antiamnestic effect on the models of amnesia provoked by scopolamine or electroshock. Tolyl-containing GABA analog (tolibut, 20 mg/kg) exhibited antiamnestic activity only on the model of electroshock-induced amnesia. Baclofen and, to a lesser extent, tolibut alleviated seizures provoked by electroshock, i.e. both agents exerted anticonvulsant effect. All examined GABA aryl derivatives demonstrated neuroprotective properties on the maximum electroshock model: they shortened the duration of coma and shortened the period of spontaneous motor activity recovery. In addition, these agents decreased the severity of passive avoidance amnesia and behavioral deficit in the open field test in rats exposed to electroshock. The greatest neuroprotective properties were exhibited by phenyl-containing GABA analog phenibut.

[Glutamate lonotropic Receptors: Structure, Localisation, Function].

The data on the structure, location and function of ionotropic glutamate receptors is shown. These include NMDA-, AMPA-, kainate and orphan receptor, activation them ensures the formation of an action potential. The ionotropic receptors are present in the CNS and peripheral organs. There are a large number of them allosteric modulators, agonists and antagonists. NMDA- and AMPA-receptors play a key role in the origin and manifestation of long-term potentiation. When NMDA- and AMPA-receptors are hyperactivity excitotoxicity arises--a pathological process that causes damage and death of neurons. The ionotropic glutamate receptors are involved in the regulation of mental functions, respiratory, sensory, cardiovascular, nociceptive, etc. g. systems.

[Glutamate Metabotropic Receptors: Structure, Localisation, Functions].

The data on the structure, location and functions of the metabotropic glutamate receptor is shown. The family consists of 8 mGluRs subtypes and is divided into three groups: I group--mGluRs1/mGluRs5, II group--mGluRs2/mGluRs3, III group--mGluRs4/mGluRs6/mGluRs7/mGluRs8. They are associated with G-protein; signaling in the cells is carried out by IP3 or adenylate cyclase signaling pathways, in the result of which, mGluRs modify glial and neuronal excitability. Receptors are localized in the CNS and periphery in non-neuronal tissues: bone, heart, kidney, pancreas pod and platelets, the gastrointestinal tract, immune system. Their participation in the mechanisms of neurodegenerative diseases, mental and cognitive disorders, autoimmune processes, etc. is displayed. Agonists, antagonists, allosteric modulators of mGluRs are considered as potential medicines for treatment of mental diseases, including depression, fragile X syndrome, anxiety, obsessive-compulsive disorders, Parkinson's disease, etc.

[Study of Mental Functions Offspring of Rats with Experimental Preeclampsia in Postnatal Ontogenesis].

The postnatal development of offspring's mental functions from rats with experimental preeclampsia caused by the replacement of drinking water by 1.8% sodium chloride solution from the 1st day of pregnancy until delivery was studied. Animals born by females with complicated pregnancy have a high level of anxiety, de- creased, motor, orienting-investigative activity, cognitive impairment in postnatal ontogenesis, compared with the offspring from rats of the control group. This model can be used in research related to the evaluation of animals born to females with the EP, as well as to search for new, effective agents for the purpose-of correcting deviations in nental development in children born to mothers with preeclampsia.

[INFLUENCE OF A NEW SUBSTANCE WITH ANTIDEPRESSANT ACTIVITY ON ORGANO- AND FETOGENESIS PROCESSES REGISTERED DURING ANTHENATAL PERIOD.]

Experiments on pregnant female rats showed that the beta-phenylglutaminic acid hydrochloride derivative neuroglutam (glutaron), exhibiting antidepressant and anxiolytic activity upon intragastric administration in doses of 26, 130 and 650 mg/kg to female rats from 6 to 16 days of pregnancy, does not impair organo- and fetogenesis processes (developments of fetus) registered during the anthenatal period, decreases fetal death, and activates the processes of prenatal development of the fetus bv 11.1% (p < 0.001), 8.3% (p < 0.001), and 2.8% (p < 0.05), respectively.

[COMPARATIVE CEREBROPROTECTIVE EFFECT OF PREVENTIVE ADMINISTRATION OF MAGNESIUM HYDROXYBUTYRATE VERSUS MAGNESIUM SULFATE AND CAVINTON IN RATS WITH COMMON CAROTID ARTERY OCCLUSION].

Dose-dependent cerebroprotective effect of magnesium hydroxybutyrate (MHB) on common carotid artery occlusion model in rats was established. Administration of 150 mg/kg MHB led to significant decrease in animal mortality (up to 9.3 times) in comparison to control (p < 0.05). This MHB dose also produced significant decrease of neurological deficit on the McGraw scale in comparison to control and magnesium sulfate (50% and 20%, respectively). The MHB treated animals also showed improved locomotor and exploratory performance in the open-field test and retained memory performance in the passive avoidance test and extrapolation escape task test. The administration of 150 mg/kg MHB produced three-fold (p < 0.05) decrease of brain edema in animals with cerebral blood flow impairment in comparison to animals treated with magnesium sulfate and cavinton.