[Effects of ultracaine on the local blood flow of the gum and on the development of cerebral seizures in experiment].

We have studied the effect of ultracaine DS forte on local blood flow of the rat gum as well as on the development of the convulsion activity of the brain at systemic injection. Experiments were carried out on 12 mongrel albino mail rats of 200-250 g weight. In the I group of animals under the light chloral hydrate anesthesia we studied the changes of local blood flow in the rat gum of lower jaw after ultracaine DS forte injection (right side) and the similar quantity of phisiological solution (left side).

[Changes in emotional state and learning process disorders in rats with experimental hepatic encephalopathy].

Animal models of liver failure are widely used for research of morphological and functional changes and pathogenetic mechanisms of hepatic encephalopathy. Changes in learning process and emotional state of rats, which were administered intraperitoneally (Phenobarbiton 40 mg/kg/day) for five days and then subcutaneously (Acetaminophen 1000 mg/kg) are described. Behaviour of rats was studied in the "open field".

[Local blood flow in the dorsal hippocampus and cerebellar cortex in progeny of iodine-deficient rats].

Experimental studies show depressive behavior in rats caused by hypothyroidism and antidepressant effect of thyroid hormones. The present study analyses changes in the hippocampal and cerebellar cortex local blood flow in the progeny of rats suffering from iodine deficiency before mating and during the whole period of gestation. The diet with very low iodine content results in a decrease of local blood flow in both brain structures, but the greatest changes were observed in hippocampus.

[Assessment of the lower threshold in autoregulation of the blood supply of the optic nerve disk].

Existence of the autoregulation phenomenon in the blood supply system of the optic nerve has been established in the 1990; however, some of its quantitative and qualitative characteristics still require clarification. The goal of the present work was assessment of the lower margin in autoregulation of the blood supply of the optic nerve in the rabbit in conditions of attenuated level of perfusion pressure. Total of six adult rabbits weighing 2.

[Altered ability to learn of rat offspring with iodine deficiency].

Experimental data demonstrate that hypothyroidism could result in depressive behavior and subsequently thyroid hormones could act as antidepressants. Postnatal changes in learning ability, memory and emotional status in posterity of rats, which have experienced different level of iodine deficiency before conception and during all gestation period were investigated in this study. Results obtained suggest that sudden iodine deprivation before and during gestation led to a significant neurological defect, which was represented by loss of ability to learn, one of the most important functions of brain in newborn and by evidence of depression.

[The models of hepatic insufficiency and encephalopathy in animals].

The majority of the investigation methods of biochemical, morphological and metabolic disorders in hepatic insufficiency and encephalopathy occurrence are inadequate in use in clinical conditions because their invasiveness frequently creates dangerous situations to the patient life and health. That's why, to characterize the mechanisms, constituting the hepatic and cerebral damages base, for testing of a new medicinal preparations, aprobation of a new theoretical and clinical hypotheses, the models of an acute and chronic hepatic insufficiency are applied on the animals, permitting to unify the age, genetic peculiarities and physiological parameters of the individuals involved in experiments, the pathology character, its severity and longevity. Homogeneity of these indexes permits to estimate molecular, structural and functional disorders, laying in the base of pathological process.

[Aminoguanidine decreases the brain damage in rats neonatally exposed to hypoxic-ischemic influences].

Seven days old rats (n=30) were divided into five groups (6 animals in each). Three groups underwent hypoxic-ischemic event (occlusion of right common carotid artery lasting 2,5 hours and breathing with 8% oxygen and 92% of nitrogen mixture). The rats of the fifth group, after completion of hypoxic-ischemic impact and following a daily reoxygenation (for three days) were injected (i/p) with selective inhibitor of nitric oxide inducible synthase, in a dose of 300 mg/kg.

[Effect of fentanyl and morphine on local blood flow and tissue oxygen tension in cortical frontal-parietal area and nucleus accumbens in albino rats].

The aim of this study was to examine effects of i.p. injected Fentanyl (0.

[Behavioral disorders caused by acute and chronic manganese intoxications of white rats].

Single per oral administration of manganese chloride induced an obvious reversible diminishing of locomotor activity in white rats as well as deterioration of avoidance response to unconditioned and conditioned stimuli, prolongation of the conditioning latency, and a temporary deterioration of learning. Chronic manganese intoxication produced an irreversible learning disability and a slight memory disorders.

[Current concepts of involvement of glutamate in ischemic damage of the brain tissue].

Glutamate neurotoxicity cannot be considered the only reason for neuronal damage. Other neurotransmitters and molecular messengers like nitric oxide, may be involved in the toxic effect of glutamate. Different conditions in focal and global ischemia, stage of the ischemic damage evolution, the degree of ischemia, and activation of glutamate receptors, should also be taken into consideration when assessing a neurological outcome.

[The effect of plaferon on cerebral circulatory hypoxia in rabbits].

Local cerebral blood flow (LCBF) was reduced following plaferon administration in rabbits due to impairment of the vasodilator responses of cerebral vessels or their transformation into vasoconstrictor responses, the effect being added to that of vasoconstrictor responses to vasoactive neuropeptides contained in plaferon.

[The role of preparation LB in forming a thrombotic infarct of the cerebral cortex].

Non-invasion model for photochemically induced brain infarction was used to study the effect of a the new anti-ischemic drug LB ("Plaferon") in albino rats. Intensity of a local blood flow was measured so as oxygen tension in brain cortex. Square and volume of the disturbed nervous tissue region, capillary length and density of distribution of different caliber vessels were detected by means of light microscopy in serial sections of brain cortex.

[The effect of plaferon on disorders in the rabbit brain induced by circulatory hypoxia].

The effect of plaferon on the local cerebral blood flow and brain tissue oxygen tension during transient incomplete ischemia and following recirculation, was studied. The difference revealed between experimental and control data is, probably, due to vasodilatory action of the vasoactive neuropeptides and the effect on the systems of phosphorylation.

[Local cerebral blood flow under emotional loads].

In chronic experiments on rats with sympathectomy, the local cerebral blood flow changes during electrical stimulation of septum, were studied. The emotional tension is one of the triggering mechanisms for the neurogenic link of cerebral blood flow regulation. The hypothalamic mechanisms, superior cervical ganglia and sympathetic innervation of the cerebral vessels are involved in this regulation.

[Effects of tumor necrosis factor on the tonus of cerebral arteries].

It was determined that tumor necrosis factor (TNF) is capable of decreasing the local brain's blood flow on 45.6% (in the concentration of 6 micrograms/kg); to make a spasm of the pial arteries on 39.6%.

[The neurogenic mechanism of the regulation of cerebral circulation and the linking of blood flow-metabolism function].

The neurogenic link of the CBF regulation provides the "microflow-metabolism-function" coupling by means of external innervation of the brain vessels. According to the principle of regulation through input, the latter can be the level of emotional tension (excitement) and not the current metabolic demands. The neurogenic link cannot be the mechanism of the CBF local self-regulation.

[The effect of electrical stimulation of the cerebellar fastigial nuclei on local blood flow in the brain].

In acute experiments on unanesthetized cats, continuous recording revealed an increase (30%) as well as a decrease (70%) in local blood flow in the sensomotor cortex of the left hemisphere in response to electrical stimulation (30 Hz, 30 V) of the contralateral fastigial nuclei of cerebellum. The stimulation seems to lead to a primary vasoconstriction as well as vasodilatation of the blood vessels regulating the local cerebral blood flow.

[Dynamics of oxygen tension in different areas of the hypothalamus during the sleep-wakefulness cycle].

In wakefulness and paradoxical sleep, fast waves prevailed in the PO2 oscillations in the posterior hypothalamus whereas in slow wave sleep fast oscillations of PO2 prevailed in the anterior hypothalamus and preoptic area. These shifts of the PO2 during wakefulness and PS seem to reflect an enhancement of the functional activity of the posterior hypothalamus. During slow wave sleep, the functional activity must be enhanced in the anterior hypothalamus and preoptic area, while in the posterior hypothalamus it is suppressed.

[Effect of microwave radiation on regional blood flow and tissue oxygenation in the brain].

The effect of irradiation of the central nervous system by microwaves (MW) at a frequency of 2450 MHz and power 5-40 W on the regulation of cerebral circulation and oxygen supply to the nervous tissue were studied in rabbits. Local irradiation of the exposed cerebral cortex resulted in hyperemia and hyperoxia in the zone of exposure induced by the hyperthermal effect of MW. When the region of the medulla oblongata was irradiated even with low MW power (not leading to hyperthermia), the local circulation and oxygen tension increased in the whole brain, apparently due to the impairment of the regulation of the cerebral blood flow and oxygen supply to the brain tissue.

[Organization of the process of autoregulation of cerebral blood flow].

Continuous recording of local blood flow in the cat cerebral cortex (the technique of electrochemical generation of hydrogen in brain tissue) revealed dynamic characteristics of autoregulation of the cerebral blood flow (CBF) during changes in the systemic arterial blood pressure. The autoregulation has a three-component character due to joint functioning of the mechanisms of myogenic, neurogenic and metabolic nature. The myogenic mechanism seems to protect the vascular bed of the brain from the impact of sharp changes in the intravascular pressure and is but indirectly involved in the CBF regulation, the latter being accomplished mainly by the hierarchically interacting nervous and metabolic mechanisms.

[Regulation of local cerebral blood flow: the concept of the homeostatic range].

Multichannel recording of the intensity of local blood flow in neighbouring microareas of the cortex was performed in acute experiments on cats under the conditions of: a) changes of systemic arterial pressure and b) asphyxia by the method of electrochemical generation of hydrogen. On the basis of data obtained a hypothesis was formulated on the existence of "homeostatic range" of local blood flow intensity and its displacement when the metabolic demand of nervous tissue and/or the degree of arterial blood saturation with oxygen are altered. The hypothesis explains the causes of temporal and amplitude differences in characteristics of changes of local blood flow in neighbouring microareas of the cortex under the effects of general character as well as the mechanism responsible for the development of posthypoxic hyperemia.

[Dynamics of the oxygen tension in the hippocampus and sensorimotor cortex during the wakefulness-sleep cycle].

Recording of the PO2 dynamics in the hippocampus and sensorimotor cortex revealed that the level of PO2 changes rather easily and dramatically depending on emotional tension of the organism during different phases of sleep and wakefulness and being, probably, related to the functional shifts occurring in these structures. On the basis of the percentage of periodical constituents of the PO2 oscillations it may be concluded that the functional activity in the dorsal hippocampus is enhanced during active wakefulness and paradoxical phase of sleep (PS); while during passive wakefulness and slow sleep it is depressed. The maximum occurs in the PS and minimum--in the slow sleep.