[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). According to our data, in the right gum, the rate of local blood flow decreases statistically significantly at 18%, while the injection of physiological solution did not result in any changes. In the II group, experiments were carried out on the animals with bipolar electrodes in neocortex, as well as in the right and the left dorsal hippocampus. On the fifth day after surgical intervention, on the background of registration of electric activity of the above stated structures 0,03-0,04 ml of ultracaine Ds forte was injected intraperitoneally, which did not result in any significant deviation on the encephalogram. 10-fold doze injection was followed by abortion of epileptic discharges (0,3 ml), but repeated injection of 0,3 ml of preparation resulted in generalized clone-tonus type seizure activity. Simultaneously, clone-tonus type behavioral manifestation was revealed.

[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". Experimental animals in comparison with the control group had decreased position-finding-exploring activity although the motor activity and the fear feeling level weren't changed. The testing in the multi branch maze showed that the experimental animal's learning ability was greatly decreased--from the start platform of the maze to the nest they made more mistakes and spent more time than the control group animals, and even at the end of the maze session successful completion of task (to reach the nest) wasn't exceeding 60%.

[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. Addition of the iodine to the diet eliminates the above blood flow changes.

[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 2.5-3.0 kg, anesthetized with urethane (0.9-1.1 g/kg) were investigated in acute experiments. Intensity of the local blood flow in the optic nerve disk was evaluated quantitatively by means of the hydrogen clearance. The frontal chamber of an eye was punctured with syringe needle, which via silicon tube was attached to the reservoir filled with artificial aqueous humor. Adjustment of vertical position of the reservoir provided different levels of the intraocular pressure. Calculation of the perfusion pressure of the eye was made according to mean level of the systemic arterial pressure, intraocular pressure, and a constant, which depends on an animal species. The results obtained allow suggesting with a certain degree of precision that elevation of the intraocular pressure to about 40-50 mmHg does not alter the blood supply of the optic nerve disk. Its further increase however leads to almost linear dependence between elevation of the intraocular pressure and decrease of the blood supply of the optic nerve disk. Meanwhile, the systemic arterial pressure should be considered as well, because volume of the perfusion pressure in the eye is determined by difference between systemic arterial- and intraocular pressures.

[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. Iodine supply to the diet of female rats eliminates these effects completely.

[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. The rats of the fourth group were injected with 150 mg/kg of the selective inhibitor of nitric oxide synthase -- aminoguanidine (150 mg/kg); the animals of the third group were injected with saline (50 ml). The second group contained the shame-operated animals and the first group -- intact (control) animals. An intensity of local cerebral blood flow in fronto-parietal area of neocortex was measured by means of hydrogen clearance technique. In the right hemisphere (ipsilateral to occluded common carotid artery) of the animals of the third group significant decrease, and in contralateral hemisphere (left) temporal increase of CBF did occur. Administration of aminoguanidine prevents high degree of brain damage observed in the control group of animals.

[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. We have analyzed the experimental models of hepatic insufficiency, basing on the hepatotoxins usage--acetaminophen (paracetamol), carbon tetrachloride, thioacetamide, D-galactosamine, concanavalin A, lipopolysaccharides. Every existing pharmacological model of hepatic insufficiency and encephalopathy for animals owes its own advantages and faults. The choice of a model depends on tasks of the investigation and of the animal species, involved in the procedures.

[Effect of fentanyl and morphine on local blood flow and tissue oxygen tension in cortical frontal-parietal area and nucleus accumbens in albino rats]. / Effekty fentanila i morfina na mestnyi krovotok i uroven' napriazheniia kisloroda v frontoparietal'noi oblasti kory i prilezhashchem iadre golovnogo mozga belykh krys.

The aim of this study was to examine effects of i.p. injected Fentanyl (0.005 mg/kg) and Morphine (1 mg/kg) on local cerebral blood flow (ICBF) and tissue pO2 level in frontal-parietal area of the cortex and nucleus accumbens of the rat's brain. Either fentanyl or morphine injection resulted in significant increase of local blood flow in the n.accumbens and its decrease in frontal-parietal area of cortex. Measurement of oxygen partial pressure revealed the opposite (to ICBF) changes: a decrease in n.accumbens and its increase in cortical area of the brain. Analysis of this data and electrical activity recorded from both said structures allow to conclude that they are conditioned by respective changes in functional-metabolic activity induced by intraperitoneal injection either fentanyl or morphine: its suppression in frontal-parietal area of the cortex and development of seizure-like activity in the n.accumbens.

[Current concepts of involvement of glutamate in ischemic damage of the brain tissue]. / Sovremennye predstavleniia o roli glutamata v ischemicheskikh povrezhdeniiakh tkani golovnogo mozga.

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]. / Vliianie plaferona na tsirkuliatornuiu gipoksiiu golovnogo mozga krolikov.

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]. / Rol' preparata LB v formirovanii tromboticheskogo infarkta kory bol'shogo mozga.

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. Preliminary introduction of LB was found to prevent formation of thrombotic infarction (the volume of cortical zone damaged is 85% lower as compared to the control). Anti-ischemic effect of LB implicates in vasodilatory action on cerebral vessels and also breaking pathogenic chain of ischemia development.

[The effect of plaferon on disorders in the rabbit brain induced by circulatory hypoxia]. / Effekt plaferona na vyzvannye tsirkuliatornoi gipoksiei rasstroistva v golovnom mozgu krolika.

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]. / Mestnyi mozgovoi krovotok pri émotsional'nykh nagruzkakh.

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]. / Vliianie tumornekrotiziruiushchego faktora na tonus arterii golovnogo mozga.

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%. In vitro experiments TNF increased the amplitude of the rhythmical and the tonic contractions of the brain's arteries smooth muscles (3.6 X 10(-8) M). The direct action of the TNF in the vascular wall is endothelium-dependent.

[The effect of electrical stimulation of the cerebellar fastigial nuclei on local blood flow in the brain]. / Vliianie élektricheskoi stimuliatsii fastigial'nykh iader mozzhechka na mestnyi krovotok v golovnom mozge.

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.

[The neurogenic mechanism of the regulation of cerebral circulation and the linking of blood flow-metabolism function]. / Neirogennyi mekhanizm reguliatsii mozgovogo krovoobrashcheniia i sopriazhennost' krovotok--metabolizm--funktsiia.

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 regulation of adequate blood supply of the brain for maintenance of the "function-metabolism-microflow" coupling is carried out by metabolic link of regulatory system.

[Dynamics of oxygen tension in different areas of the hypothalamus during the sleep-wakefulness cycle]. / Dinamika napriazheniia kisloroda v razlichnykh oblastiakh gipotalamusa v tsikle bodrstvovanie-son.

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.