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Biomedical subjects

A Iu Sledkov

Publications and source records attributed to A Iu Sledkov.

12 recordsLinked to original sources
PubMed1993

[The effect of adren-, cholin- and dopaminergic preparations on the formation of the high-pressure nervous syndrome in rabbits].

Behaviour and the EEG responses to electric intracranial stimulation of the frontal cortex, mesencephalic RF, dorsal hippocampus and caudate nucleus were studied in hyperbaric experiments in rabbits. Thresholds of the stimulation for all the areas were decreased at 41 ATA, the thresholds progressively decreasing at 71 and 101 ATA. Preliminary administration of various pharmacological agents activating and inhibiting different neurotransmitter systems, altered the regularity of the EEG changes and behaviour. Dopaminergic agents suppressed some signs of the nervous high-pressure syndrome.

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PubMed1992

[The polyphosphoinisitide response evoked by different neuromediators after exposure to a helium-oxygen environment under increased pressure].

Male Wistar rats were subjected to normoxic helium-oxygen mixture under 40 kg/cm2 pressure with subsequent decompression. Their brain's Ach, dopamine, glutamate, substance P were shown to change the turnover rate of the synaptosomal PPI. The findings suggest an unspecific mechanism of action of high tension helium on the neurons. The data obtained shows the high pressure neural syndrome not to be connected with metabolic change of a single neurotransmitter.

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PubMedDate not supplied

[Changes in the content of rat brain polyphosphoinositides after exposure to high partial pressures of helium and nitrogen].

Effect of the medium with high partial pressure of helium and nitrogen on the content of di- and triphosphinositides in the rat brain great hemispheres. The stay of the rats in helium-oxygen mixture under the pressure of 40 kg/cm2 for 1 h is accompanied by the true decrease in the content of the both components of polyphosphoinositides whose value does not depend on the decompression conditions. Nitrogen-oxygen mixture under the pressure of 15 and 25 kgf/cm2 also evokes a decrease of the content of di- and triphosphoinositides. The character of reduction of the content of the both components for 4 h after the stay of the rats under the pressure of 25 kgf/cm2 depends on the decompression conditions.

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PubMedDate not supplied

[The self-stimulation reaction of rabbits in a helium-oxygen environment under increased pressure].

Change of intensity of hypothalamic self-stimulation was determined in rabbits during their stay in normoxic helium-oxygen medium under the pressures of 10, 15 and 40 kgf/cm2 at various speeds of compression. The experiments conducted testify to depressive influence on the hypothalamus self-stimulation of helium-oxygen medium under increased pressure; the influence was more expressed at higher pressures and great speed of compression. It is supposed that the decrease in frequency of pedal pressures was connected with the appearance of nervous syndrome of high pressures.

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PubMedDate not supplied

[Duration of the narcotic action of nembutal under hyperbarism].

The duration of sleep induced by administration of nembutal in hyperbaric helium-oxygen, nitrogen-oxygen and helium-nitrogen-oxygen mixtures was studied on Wistar rats. Helium reduced the duration of nembutal narcosis. On the contrary, nitrogen increased its duration under high pressure. The most rapid decrease of narcosis was observed with the use of helium-nitrogen-oxygen mixture under the pressure of 40 at. The results of the study are in a good agreement with the theory of the antagonistic effects of helium and nitrogen under high pressure on the central nervous system.

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PubMedDate not supplied

[The participation of adren-, cholin- and dopaminergic mechanisms in the development of hyperbaric nitrogen narcosis in rabbits].

Behavior and EEC responses to electrical stimulation of the frontal cortex (FC), mesencephalic reticular formation (MERF), dorsal hippocampus (DH), and nucleus caudatus (NC) were investigated in hyperbaric experiments on rabbits. As compared to the control data, the thresholds of motor reaction caused by the stimulation of FC and MERF in N2/O2 mixture at 11 ATA were increased by 41% (p < 0.05) and 10% (p < 0.05), respectively, whereas those by DH and NC stimulation showed no changes as compared to the controls. During decompression to 5 ATA, the thresholds of intracranial stimulation of FC and MERF returned to the control level. After prior injection of pharmacological agents that activated or inhibited the adren-, dopamin-, and cholinergic neurotransmitter systems, different changes in behavior, EEC, and stimulation thresholds were observed in N2-O2 under high pressure. The application of the adrenergic activator ephedrine may be promising in pharmacologically correcting nitrogen narcosis.

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PubMedDate not supplied

[The effect of antiparkinson preparations on the self-stimulation reaction of rabbits in a helium-oxygen environment under increased pressure].

The authors studied hypothalamic self-stimulation of 30 rabbits in hyperbaric heliox after intraperitoneal injections of L-DOPA, melanostatin, and cyclodol. The frequency of self-stimulation was decreased with 40 atm of heliox. After L-DOPA administration, a reduction of self-stimulation was twice less than that in heliox without pharmaceuticals.

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PubMedDate not supplied

[Grooming and motor activity of rats during hyperbaric exposure].

An experiment was performed in which Wistar male rats were exposed to a N2-O2 atmosphere at 10 kgf/sm2 or He-O2 atmosphere at 10 and 40 kgf/cm2. During the experiment grooming and motor activity as well as plasma corticosterone were investigated. Irrespective of the atmosphere composition, behavioural and biochemical parameters were found to increase significantly. At 10 kgf/cm2, the grooming frequency returned to normal faster than at a higher pressure. These observations give evidence for a nonspecific effect of the above hyperbaric factors on the parameters taken under study.

Animals↗
PubMedDate not supplied

[The function of the brain structures in rabbits under the action of hyperbaric helium and nitrogen-oxygen mixtures].

Behaviour of rabbits as well as excitability thresholds of certain brain areas were determined by intracranial electrostimulation under high pressure in the heliox and nitrox media. Excitability of the mesencephalic reticular formation and of the frontal cortex in particular, decreased under 11 ata in the nitrox medium. On the contrary, measurements of the thresholds and EEG data have shown an increase in excitability in all brain regions under 41 ata of the heliox medium. Excitability increased most of all in the dorsal hippocampus and nucleus caudatus. The role of different brain structures in the symptomatics of nitrogen narcosis and high-pressure nervous syndrome is discussed.

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