[The time course of changes in the state of monoaminergic systems in the brain of mice under the acute hypoxia with hypercapnia]. / Dinamika izmenenii sostoianiia monoaminergicheskikh sistem golovnogo mozga myshei pod vliianiem ostroi gipoksii s giperkapniei.

In socially isolated male outbred albino mice, the changes of monoaminergic systems under acute hypoxia with hypercapnia were studied. In cerebral cortex, hippocampus and striatum of the right and left sides of the brain, the concentrations of norepinephrine, dopamine, serotonin and their metabolites - dihydroxyphenylacetic, homovanillic and 5-hydroxyindoleacetic acids were investigated using the HPLC method. In isolated mice, which were not subjected to hypoxia with hypercapnia, higher levels of dopamine and serotonin in the left cortex were found. There was no asymmetry in monoamines and their metabolites in other studied brain structures. 10 min after the onset of exposure, acute hypoxia with hypercapnia resulted in a right-sided increase in norepinephrine levels and a decrease in dopamine levels in the striatum and serotonin levels in the hippocampus. In the cerebral cortex, 10 min after of hypoxic exposure beginning, there was a left-sided decrease in the dopamine content, while the original asymmetry found in the cortex of intact animals disappeared. In isolated mice perished of hypoxia with hypercapnia, almost all parameters returned to the control level. The exception was the ratio of serotonin metabolite level to the neurotransmitter, which in the right cortex became lower than in control animals. In white outbred mice, the brain monoaminergic systems are suggested to be relatively resistant to the negative consequences of hypoxia and hypercapnia, and corresponding shifts resulting in the reflex brain response to changes in the gas composition of the respiratory air.

[The effect of acute hypoxia with hypercapnia on the content of monoamines in symmetrical areas of the brain in albino mice]. / Vliianie ostroi gipoksii s giperkapniei na soderzhanie monoaminov v simmetrichnykh strukturakh golovnogo mozga u belykh besporodnykh myshei.

Changes in the activity of monoaminergic systems of the left and right hemispheres of the brain after acute hypoxia with hypercapnia were investigated in male albino mice. The concentrations of dopamine (DA), serotonin (5-HT) and their metabolites dihydroxyphenylacetic (DOPAC), homovanilic (HVA) and 5-hydroxyindolacetic (5-HIAA) acids were measured by HPLC in the brain cortex, hippocampus and striatum of the right and the left hemispheres. In the control mice not exposed to hypoxia with hypercapnia, a higher concentration of DA in the left cortex was detected. No asymmetry in the content of other substances has been identified in the investigated structures. Acute hypoxia with hypercapnia led to the right-sided increase of DA and 5-HT levels and to the left-sided reduction DOPAC in the cerebral cortex. Under the condition of hypoxia with hypercapnia, in the hippocampus, the left-sided increase of the DA content was revealed. In the striatum the contents of monoamines and their metabolites were insignificantly changed. It has been concluded that acute hypoxia with hypercapnia causes asymmetric changes in monoaminergic systems of the archicortex and the neocortex.

[Central monoaminergic systems sensitivity to acute hypoxia with hypercapnia changes after the maintenance under the long-term social isolation]. / Izmenenie chuvstvitel'nosti tsentral'nykh monoaminergicheskikh sistem k ostroi gipoksii s giperkapniei pod vozdeistviem dlitel'noi sotsial'noi izoliatsii.

The experiments were performed in male albino outbred mice kept in a group and under the conditions of long-term social isolation. The changes in the monoaminergic systems of the left and right hemispheres of the brain after acute hypoxia with hypercapnia have been studied. The levels of dopamine (DA), serotonin (5-HT) and their metabolites - dioxyphenylacetic (DOPAC), homovanillic (HVA), and 5-hydroxyindoleacetic (5-HIAA) acids - were determined by HPLC in the cerebral cortex, hippocampus and striatum of the right and left sides of the brain. In the control mice kept both in the group and under the conditions of social isolation, a higher content of DA in the cortex of the left hemisphere has been found. In the other brain structures the monoamine content was symmetric. In the cerebral cortex of the mice in the group, acute hypoxia with hypercapnia led to a right-sided increase in the DA and 5HT levels. At the same time, the DOPAC content decreased in the left cortex. In mice in the group, under the hypoxia with hypercapnia conditions, the DA level in the left hippocampus increased. In the striatum, the content of monoamines and their metabolites did not change significantly. In animals kept for a long time under the conditions of social isolation, hypoxia with hypercapnia no statistically significant changes in the monoamines and their metabolites levels were found. It has been concluded that the preliminary maintenance under the conditions of prolonged social isolation changes the reaction of central monoaminergic systems to acute hypoxia with hypercapnia.

Antioxidant and Antiamnestic Effects of Potassium Comenate and Comenic Acid under Conditions of Normobaric Hypoxia with Hypercapnia.

Potassium comenate and comenic acid exhibit manifest and virtually identical antioxidant activity under conditions of hypoxia with hypercapnia. The effects of these drugs on conditioned reflex training with positive reinforcement differ significantly. Potassium comenate promotes retention of the learning capacity and memory in hypoxic rats at the level of intact control, that is, exhibits a pronounced protective antiamnestic effect, while comenic acid only facilitates training of the conditioned reflex with positive reinforcement.

[Effect of acute hypoxia with hypercapnia on the content of monoamines in symmetrical brain structures of the BALB/c male mice].

The changes in activity of monoaminergic systems of both the right and the left brain hemispheres of the BALB/c male mice after an acute hypoxia with hypercapnia were studied. The concentrations of dopamine, serotonin and their metabolites dihydroxyphenylacetic, homovanilic and 5-hydroxyindolacetic acids were measured by HPLC in the brain cortex, hippocampus and striatum of the right and the left hemispheres. The more high concentration of serotonin was revealed only in the cortex of the left hemisphere in control mice without hypoxia with hypercapnia. The asymmetry in dopamine level was not registered in all structures studied. Acute hypoxia with hypercapnia decreased the dopamine level in the striatum and the serotonin level both in the hippocampus and the brain cortex. The dopamine metabolites level was reduced in the striatum and in the brain cortex of hypoxed mice: both metabolites in the right brain cortex and only dihydroxyphenylacetic acid in the left br ain cortex. Serotonin metabolism was decreased in all brain structures studied after hypoxia with hypercapnia in mice. Therefore, serotoninergic system of the brain is more sensitive to acute hypoxia with hypercapnia than dopaminergic system.