The Level of Individual Biochemical Constants of the Brain of in the Krushinsky-Molodkina Inbred Rat Strain against the Background of Radon Inhalation During Epilepsy

Introduction: The elucidation of the mechanism of action of radon on antioxidant processes needs further research, however, based on the results of the experiment, it can be concluded that studies on experimental animals have shown that, while inhaling Tskhaltubo water, the phenomenon of hormesis develops. Methods: we placed 10 experimental animals (KM rats) in Radon contained mineral water spa`s sauna.  Inhalation of radon-water was administered through the nose, for 10 minutes, once a day, in conditions of high humidity (about 90%) for 10 days. Results: Hormesis regulates oxidative processes in the brain due to the activation of antioxidants expressed in a decrease in existing epileptic seizures and is expressed in the activation of Na / K-ATPase and specific glutaminergic neurons of the "attack center" of the hypothalamus but also with the activation of the entire adaptive-compensatory system. Conclusion: Inhalation of radon contained water can be considered as a method of treatment with an anticonvulsant effect confirmed by experimental studies.

Ultrastructural Changes in the Penumbra of the Local Cerebral Infarction in Rats

We studied changes in the ultrastructure of synapses and myelin nerve fibers that develop in the penumbra in 4 and 12 h and 2 and 4 days after modeling infarction in the frontoparietal cortex in rats. Ischemic stroke was induced by injection of a photosensitive dye into their bloodstream followed by illumination of the brain surface with a halogen lamp. Visible ultrastructural changes were observed in the penumbra zone, namely in the axodendritic and axospinous synapses; they consisted in polymorphism and disorganization of synaptic vesicles, mitochondrial swelling, swelling and vacuolization of the postsynaptic fragments of dendrites, and shortening and osmiophilia of the active zone. In the presynaptic terminals, clear-cut signs of transformation were observed only in 2 and 4 days after infarction modeling. These terminals were located at the ends of the degenerated myelinated axons of necrotic neurons. These findings demonstrate irreversible changes in the ultrastructure of synapses in the penumbra in 2-4 days after infarction and indicate the necessity of early treatment of strokes.

RADON HORMESIS IN EPILEPTIC PATHOGENESIS AND PREDICTORS OF OXIDATIVE STRESS

Numerous experimental and clinical studies have shown that oxidative stress (OS) plays an important role in the development of epilepsy. The epileptic seizures themselves are caused by OS and, under conditions of a hypermetabolic state, cause an intensive production of reactive oxygen species (ROS) in the brain. The reason for this is called a change in the energy balance in the brain. According to the literature, ROS and other markers of oxidative stress were observed in the brain after seizures. Based on the above data, the aim of our study was to study a short-term 5-day (5 min) inhalation of radonized water from Tskhaltubo using an epileptic model of the Krushinsky-Molotkin line in rats and to identify changes in markers of oxidative stress in rats. Predictors of oxidative stress were studied, PAT, D-ROM (reactive oxygen metabolite index), OBRI (oxidative stress balance risk index) and OSI (oxidative stress index) were evaluated to assess the antioxidant capacity of plasma. Based on the data obtained, it can be concluded that: inhalation of Tskhaltubinsk water develops the effect of hormesis, which causes positive changes in all of the above markers of oxidative stress in the brain. Based on the data presented, inhalation of Tskhaltubo water can be considered as one of the methods for removing and treating convulsive phenomena, which is confirmed by experimental studies.

Some Aspects of Role of Nitric Oxide in the Mechanisms of Hypertension (Experimental Study)

Background

Modulation of endothelial function is a therapeutic option to reduce some of the significant complications of hypertension. However, the relationship between endothelial dysfunction reduced nitric oxide (NO) production, and the development of hypertension is not fully understood. To establish a potential pathogenetic link between impaired NO synthesis and hypertension, we investigated the results of competitive interaction of the substrate of NO synthase, L-arginine, and its analog, an non-selective inhibitor of NO synthase, N-nitro-methyl ether-L-arginine (L-NAME), in experimental rats.

Methods

Arterial hypertension was induced in male Wistar rats by intraperitoneal administration of L-NAME (Sigma-Aldrich) for 4 - 7 weeks. During the last 3 weeks, to a separate group of animals simultaneously with L-NAME, L-arginine (Sigma-Aldrich) was administered. In animals monitored for systolic and diastolic pressure, the level of NO in blood samples was determined spectrophotometrically using a Griess reagent.

Results

Administration of L-NAME for 4 - 7 weeks induced an irreversible decrease of NO content in blood, a reversible increase of systolic pressure (SP) and diastolic pressure (DP), and an irreversible increase in pulse pressure (PP). In rats against the background of 7 weeks of intraperitoneal administration of L-NAME, during the last 3 weeks, they were injected with L-arginine, the SP and DP indices returned to their initial values, PP decreased and the NO content in arterial blood increased.

Conclusions

The results of the study indicate the presence of residual endothelial dysfunction (characterized by insufficient NO) after the correction of hypertension. Therefore, in developing the new therapeutic approaches for the treatment of hypertension, it is necessary to include drugs that, in addition to correcting blood pressure, will support normalization, and potentiation of endothelial function and endogenous NO synthesis.

CHANGES IN ARTERIOLE REACTIVITY TO NORADRENALINE UNDER CONDITIONS OF HYPERHOMOCYSTEINEMIA

The aim of the research was the experimental study of one of the possible mechanisms performing contractile activity of arterioles in hyperhomocysteinemic animals. Moderate hyperhomocysteinemia was induced in male rats (120-160 g., n=12) by adding L-methionine to the drinking water during 4 weeks. Control animals (n=12) administered the normal water without limitation. The experiments were performed on the isolated arterioles of first line of the rat's soft muscle (Gracilis). Reactions were studied on normal and deendothelized segments of arterioles. Increased homocysteine has been found to be associated with noradrenaline-induced vascular constriction and decreased endothelium-dependent dilatation in the arterioles of the muscle. It has been suggested that the increased reactivity of blood to noradrenaline in animals in the group of hyperhomocysteinemia must have been due to impaired endothelial nitric oxide synthesis.

EFFECTS OF HIGH AND LOW DOSES OF ETHANOL, GIVEN TO RATS DURING THE PROCESS OF PREGNANCY, ON THE BEHAVIOR AND THE BLOOD RHEOLOGICAL PROPERTIES OF THEIR OFFSPRINGS

In our experiments it has been established that during pregnancy the impact of ethanol high dose on rats' offspring induces a well pronounced increase of plasma viscosity, which is extremely important in blood circulation. The disruption of blood circulation causes a hypoxic condition (especially, in nervous tissues) and the disturbance of its functioning. This is the result of what has been seen in the behavioral experiments of female rats' offspring under the influence of ethanol high dose. We consider that it has a crucial importance, as we speak about the remote results of ethanol consumption, which are manifested not only in rats, taking ethanol, but also in its offspring.

[SOME PHYSIOLOGICAL PROCESSES IN ISCHEMIC PENUMBRA OF THE BRAIN (REVIEW)]

The zone of penumbra in ischemic brain tissue lies below the local cerebral blood flow threshold for electrocortical silence but above that for anoxic depolarization and massive ionic dyshomeostasis. Conflicting data concerning the width of therapeutic window in which successful reperfusion of blood still is possible, are cited in this paper. The role of temperature in development of ischemic stroke is also considered. There are data that even small degrees of brain temperature alterations crucially affect the outcome of ischemic insults. The lowering of intraischemic brain temperature by just 2 to 30C is capable of diminishing the volume of infarction up to 70 to 80%. Hypothermia modifies a variety of intracellular processes and markedly delaying the process of cell death, hypothermia appears to widen the therapeutic window.

EFFECT OF FREE RADICALS ON CALCITONIN-GENE-RELATED PEPTIDE MEDIATED VASODILATION

It is known that in some pathological conditions, due to the formation of a large number of free oxygen radicals, the cardiovascular system is severely affected. However, the effect of free radicals on CGRP-mediated vasodilation remains unclear. The aim of this work was to study the effect of free radicals on CGRP-mediated neurogenic vasodilation on preparations of an isolated rabbit lingual artery. The experiments were performed on the lingual artery preparations of 6 rabbits of the Chinchilla breed of both sexes. The contractile-relaxation activity of isolated preparations, both with intact endothelial layer and deendotelized, were studied in isometric mode on a strain-gauge unit using mechanotrons of the 6 MX1C type. Our experiments showed that free radicals can disrupt the reactivity of the vascular wall both in the presence and in the absence of endothelium-dependent relaxation factors and that is might be considered as a main conclusion of this study.

Neuroprotective treatment of cerebral infarction: an experimental study

We investigated the effect of the amniotic-derived peptide Plaferon-LB on cerebral tissue damage during photochemical insults in rats. Plaferon-LB (US patent number: 20070123467 A1) was extracted from the amniochorionic membrane of a human placenta and showed a relatively strong antihypoxic effect compared to other interferon. Thrombotic infarction was induced by photochemical illumination after intravenous injection of Rose Bengal. The infarct volume, cerebral tissue oxygen tension, cerebral blood flow, and capillary damage were measured in the following groups: untreated control rats, Plaferon-LB-alone rats, insult-alone rats, and insult in Plaferon-LB pretreated rats. The technique of electron paramagnetic resonance (EPR) spectroscopy was used to study free-radical metabolites in the blood and brain tissue ex vivo. Plaferon-LB alone had no effect on systemic blood pressure, cerebral blood flow, and reactive metabolites in the brains of intact animals. In the insult-alone group, a focal hemorrhage was observed in the ischemic area. The cerebral blood flow and tissue oxygen pressure declined to zero within an hour and remained at this level throughout the insult. The treatment with Plaferon-LB 0.5 hr before illumination resulted in a significant reduction of the median infarct size in the insult-alone group. The total length and percentage ratio of thrombotic vessels were significantly diminished in the infarct area. The intensity of Fe2+, Mn2+ -, Mo5+ -xanthinoxidase-containing complexes, and nitric oxide EPR signals was decreased, and the electron transport in the mitochondria was normalized. The results indicate a significant beneficial effect of Plaferon-LB on cerebral infarct, which is likely due to its antioxidative properties.

Hyperthermia-induced morphological changes in cerebral tissue of the rat

The sensitivity of cerebral tissue to hyperthermia, its immediate effect, manifested by histological changes and the role of local blood flow, blood rheological properties, and the possible role of free radicals in development of mentioned changes have been studied. Through the cranial window local area of cerebral surface was irrigated by artificial CSF heated up to 41, 43 or 45 degrees C. Serial brain coronal sections 50 microm thick were analyzed under light microscope. Local Cerebral Blood Flow was measured by thermo-clearance method. Blood rheological properties were changed by injection of Dextran T-500 and free radicals existence was controlled by DMSO injection. High sensitivity of cerebral tissue to hyperthermic exposure even at a temperature of 41 degrees C has been confirmed. We consider cerebrovascular thrombosis as one of the most significant complication of brain hyperthermia. Deteriorated blood rheological properties aggravates hyperthermia-induced cerebral lesion. Administration of free radicals scavengers can partially lessen hyperthermia induced cerebral lesion.

[Regulatory mechanims of smooth muscles contractility in the cerebral arteries]

The results obtained in the experiments on large cerebral arteries are summarized in the presented article. It was declared that direct application of these data to the properties and peculiarities of contractile activity having place in smooth muscles of the small arteries is not fully admissible, because these vessels have different spatial organization and rheological properties. More over, in accordance with the functional heterogeneity conception, such an application is not generally acceptable even from the theoretical point of view. This conception imply the specific analysis of neurohumoral signals effectiveness in every section of vascular bed, revival of electro- and chemo-excitable calcium channels peculiarities and taking into consideration features of innervations and spatial orientation of smooth muscle fibers in the vascular wall. It must be underlined, that on the level of small cortical arteries studies devoted to mentioned questions are not yet described in the literature.