[Catecholamines, nitrogen oxide, and resistivity to stressor lesions: effect of adaptation to hypoxia]. / Katekholaminy, oksid azota i ustoichivost' k stressornym povrezhdeniiam: vliianie adaptatsii k gipoksii.

Pronouncement of stress-induced disturbance of searching behaviour (using "open field" test) and stomach ulceration were compared for the first time with activity of the catecholamine system in hypothalamus and striatum and also with activity of the stress-limiting system of nitric oxide (NO) in the rats of two strains August and Wistar, which differ in their resistance against stress-induced cardiovascular disorders. The effect of prior adaptation to hypobaric hypoxia on these disorders was also studied. August rats appeared to be more resistant than Wistar rats against stress-induced disturbance of the searching behaviour and stomach ulceration. Results of measuring the content of catecholamines in brain structures and the content of NO stable metabolites nitrate/nitrite in plasma suggested that these differences could be due to the stress activation of the nigro-striatal dopaminergic system in August rats, which was not observed in Wistar rats, and also to the higher production of NO in August than in Wistar rats. Adaptation to hypoxia considerably restricted these stress disorders in rats of both strains. Importantly, the protective effects were associated with activation of the nigro-striatal dopaminergic system in all the animals. In the result, adapted Wistar rats, as distinct from non-adapted Wistar rats, displayed a stress activation of this system. The protective effects of adaptation were also accompanied by an increased NO synthesis. Taken together, the data suggest an important role of the responsiveness of the brain dopaminergic system and NO system in the mechanism of resistance against stress-induced disturbances.

[Sodium oxybutyrate normalizes the central nervous system functions in the progeny of rats subjected to hypobaric hypoxia during pregnancy]. / Natriia oksibutirat mormalizuet funktsii tsentral'noi nervnoi sistemy u potomstva krys, podvergshikhsia gipobaricheskoi gipoksii vo vremia beremennosti.

Two-hour hypobaric hypoxia of rats on day 15 of their pregnancy led to a reduction in weight gain of pups within 20 days after birth, disturbed memory in active and passive paradigms, changed adaptive behavior in the extrapolatory water avoidance test, and impaired sleep in adult animals. Postnatal treatment with sodium hydroxybutyrate given in a dose of 50 mg/kg/day on days 8 to 20 of life normalized mnestic functions of the brain, the process of falling asleep, and physical development which had been impaired by intrauterine hypoxia.

[Behavior disorder in rats induced by Madopar and its pharmacological correction]. / Narushenie povedeniia krys, vyzvannoe madoparom i ego farmakologicheskaia korrektsiia.

Administration to rats of madopar in a dose of 125 mg/kg produced stereotypy, decrease in the exploration activity in the open field test, loss of the ability to decide the extrapolation problem (escape out of acute stressful situation). The latter type of behavioral pathology alone was selectively averted by administering the classical neuroleptics fluorophenazine, haloperidol and its analog azaperone. Atypical neuroleptics and the the antidepressant imipramine were less effective and reduced but animals' motor excitation induced by madopar according to the extrapolation avoidance test. The tranquilizer phenazepam did not influence behavioral pathology in this test. The data obtained suggest that impairment of the animals' behavioral pattern in the extrapolation avoidance test on madopar administration in a dose of 125 mg/kg may serve an experimental model for evaluating the neuroleptic effect of the drugs.

[Effect of chronic stress on the ultrastructure of the myocardium and hypothalamus of "emotional" and "nonemotional" rats]. / Vliianie khronicheskogo stressa na ul'trastrukturu miokarda i gipotalamusa "émotsional'nykh" i "neémotsional'nykh" krys.

The influence of chronic stress on the ultrastructure of the myocardium and hypothalamus was studied in experiments on male rats with different levels of emotional-behavioral reactivity. "Emotional" rats manifested a pronounced increase in glycogen granules in myocytes and intercellular space, appearance of the areas of overcontraction of myofibrils, conglomerates of aggregated platelets in myocardial capillaries, and red cell egress from myocardial and hypothalamic capillaries. Alterations in the ultrastructure of the myocardium and hypothalamus in "nonemotional" rats were less marked and consisted in the appearance of the areas of overcontraction of myofibrils, enlargement of sarcoplasmic reticulum caverns, and in an increase in the lipid content in cardiomyocytes. The ultrastructural changes in the myocardium and hypothalamus of "emotional" and "nonemotional" rats indicate different reactivity of the animals and are likely to be accounted for by different levels of activation of their adrenergic systems.

[Comparative study of the psychotropic activity of tuftsin and its analogs]. / Sravnitel'noe izuchenie psikhotropnoi aktivnosti taftsina i ego analogov.

Tuftsin and its Leu1 and D-Arg4 analogs displayed stimulating activity in experimental behavioral despair in mice. In rats with different types of emotional reactions and with destroyed catecholamine terminals (6-OHDA treatment), tuftsin increased exploratory activity, with fear manifestations being decreased and avoidance behavior improved. This was shown while testing the rats in the "open field" and according to the ability to accomplish an extrapolation task of avoiding critical stress-situation. Leu1-tuftsin increased the emotional stress and sharply hindered the avoidance reaction, while D-Arg4-tuftsin modulated the behavior of the animals with increased emotional reactivity and made the avoidance behavior prompter. Pentapeptide, an inhibitor of tuftsin stimulation of phagocytosis, had no significant effect on the behavior. Modifications in the structure of tuftsin resulted both in the changes in phagocytosis-stimulating activity and the appearance of other psychotropic effects.

[Effect of chronic stress on the behavior, bodily condition, and cerebral tyrosine hydroxylase activity of "emotional" and "unemotional" rats]. / Vliianie khronicheskogo stressa na povedenie, somaticheskoe sostoianie i aktivnost' tirozingidroksilazy mozga "émotsional'nykh" i "neémotsional'nykh" krys.

The relationship between behavior manifestations, somatic alterations and brain tyrosine hydroxylase activity was studied in "emotional" and in "non-emotional" rats exposed to chronic stress. The drastic increase in tyrosine hydroxylase activity in the hypothalamus and striatum after stress correlates with disturbances in behavior, somatic defects (ulcers, erosions) in "emotional" rats as compared with "non-emotional" ones.