[Comparison of reabsorption of osmotically free water in the bud and energy of interaction of vasotocin analogs with a V2-receptor].

The calculated values of the binding energy of nonapeptides with receptors in docking with their influence on reabsorption of osmotically free water in a rat bud in vivo were compared. Vasotocin and some its analogs were intramuscularly introduced to non-narcotized rat females of the Wistar line in doses from 0.1 pmol to 0.5 nmol/kg of body weight against the background of peroral water load (50 ml/kg of body weight). A significant correlation between the calculated interaction energy of peptides with V2-receptors and an increase of reabsorption of osmotically free water in the rat bud stimulated by injection of nonapeptides was found. The results evidence that alterations in rat bud in vivo caused by analogs of vasotocin and their interactions with V2-receptors can be accurately simulated.

[Comparative-physiological study of leukocyte participation in initiation of lipid peroxidation during nitrite intoxication in rats and muskrats].

The study is carried out on Wistar white rats non-adapted to oxygen deficit and on semiaquatic rodents muskrats adapted to periodic arrest of respiration during diving under conditions of Nembutal narcosis. It has been revealed that 1 h after a subcutaneous injection of sodium nitrite (3 mg/100 g body mass), intensification of lipid peroxidation (LPO) in the muskrat brain is absent, the activity of the antioxidant enzyme catalase increasing 16 times (p < 0/01) as compared with control injected with equivalent saline volume. In heart and liver, a statistically significant decrease of the content of LPO products active in the test with 2-thionarbituric acid; in the femoral muscle tissue, the LPO intensity does not change. In rats, unlike muskrats, after injection of sodium nitrite, an increase of LPO is recorded in brain, while a decrease of the LPO product content in the femoral muscle; in liver the LPO intensity did not change. In muskrats, the sodium nitrite administration leads to a decrease of the leukocyte spontaneous mobility, of lymphocyte cytokine-producing activity, and ofneutrophil bactericidal activity (by the content of cationic proteins in neutrophilic phagocytes), whereas in rats the leukocyte mobility does not change, only the blood neutrophil bactericidal activity decreases. The ability of neutrophils to produce the superoxide anion during the nitrite intoxication does not change both in rats and in muskrats. The obtained data allow concluding that under conditions of Nembutal narcosis the leukocyte functional activity on the background of nitrite intoxication is suppressed to the greater degree in the muskrats genotypically adapted to oxygen deficit than in immunocompetent cell of the rodents not adapted to hypoxia.

[Bioelectrical reactions on the surface of the mamma in the goat]. / Bioélektricheskie reaktsii na poverkhnosti molochnoi zhelezy kozy.

Spontaneous and evoked biopotentials were recorded on the mammary gland surface in goats. The biopotentials appear in the course of secretion during milk ejection as well as under electrical, mechanical and hormonal actions. They might be considered as adequate indices of secretion and ejection processes in the mammary gland.

[The comparative characteristics of the heart rhythm in cetaceans]. / Sravnitel'naia kharakteristika serdechnogo ritma u kitoobraznykh.

In Amazon River dolphins, bottle-nosed dolphins and white whales, comparative studies have been made on cardiac electrical activity using electrocardiographic and telemetric techniques. In all the species investigated, certain dependence of cardiac cycle duration on the phase of respiratory pause was observed. A pronounced bradycardia was noted in diving animals which reflects the level of their adaptation to hypoxia and hypoxemia. Autocorrelation functions of the dynamic sequences of cardiac intervals were calculated. The presence of "slow" waves in cardiac cycle was shown which were considerably increased during diving.