[State of autonomic regulation of heart rhythm in young and aged rats before and after application of different regimens of rhythmic extreme cooling.].

The influence of various rhythmic extreme cold effects on the state of autonomic regulation of heart rate in young and aged rats was studied. According to the spectral analysis of heart rate variability, it has been found that in young rats, using rhythmic extreme cold exposures (RECE) temperature regimens of (-120 °С; -120 °С; -120 °С) and (-60 °С; -120 °С; -120 °С) significantly increased adaptive capabilities of the body due to the activation of its own homeostatic regulatory systems. At the same time, the combined regimen of RECE (-60 °С; 120 °С; -120 °С) occurred to be the most optimal for aged animals, since its use was not accompanied with an excessive activation of sympathoadrenal system at the early stages of experimental studies, in contrast to the regimen (120 °С; -120 °С; -120 °С).

[Structural changes in myocardium of aged rats on background at stress-induced arterial hypertension.].

Here, we assessed the histological changes in myocardial structure in old rats against the background of persistent arterial hypertension. This study was aimed to investigate the structural organization of tissues and vessels of animal myocardium to days 3, 7 and 30 after development of stress-induced arterial hypertension. The experiments were performed in 28-30-month-old white outbred male rats.

[Lipid peroxidation during extreme hyperthermia of rats].

The influence of extremal cryoeffects on the state of prooxidant and antioxidant systems in the blood serum and heart tissues was studied in young and old rats. It is shown that kinematic parameters of chemiluminescence after cold effects are less expressed in the blood serum of old animals than in young ones. The level of TBA-active products in the blood of young rats was lower than in old ones.

[Effect of nitric oxide on 5'-nucleotidase activity of the membrane rafts in the smooth muscle cells].

We investigated the effect of nitric oxide on the catalytic activity of 5'-nucleotidase associated with insoluble membrane domains (rafts) of pig stomach smooth muscle. The low concentration (0.1-10.

[Catalytic characteristics of 5'-nucleotidase in the structure of cell membrane rafts in smooth muscles].

5'-nucleotidase (EN 3.1.3.