[Free radical mechanism of the cold stress development in rats]. / Svobodnoradikal'nyi mekhanizm razvitiia kholodovogo stressa u krys.

Development of cold stress in rats is characterized by sharp activation of lipid peroxidation accompanied by a considerable increase of the diene conjugates level and Schiff bases in tissues of brain, liver and in erythrocytes. There is a shift in the prooxidant--antioxidant balance of the organism in the form of amplification of xanthine oxidase prooxidant enzymatic activity in the brain and liver, and a decrease of myeloperoxidase activity in blood neutrophiles of rats. The attrition at cold stress, mainly, of enzymatic endocellular antioxidant system as the result of inhibition of superoxide dismutase, catalase, glutathione reductase activities in brain, liver and erythrocytes is indemnified by activation of non-enzymatic antioxidant mechanisms. In conditions of cold stress, destabilization of erythrocyte membranes of rats described by a decrease of the microviscosity of protein-lipid contact zones and reduction of degree of immersing of proteins in lipid membrane owing to exhibiting proteins from the hydrophobic zone of membranes, or their aggregate, increase of polarity of lipid phase and negative surface charge, is marked.

[Features of regulating delta sleep-inducing peptide by free radical processes in tissue and erythrocyte membranes in intact animals and under stress]. / Osobennosti reguliatsii del'ta-son indutsiruiushchim peptidom svobodnoradikal'nykh protesessov v tkaniakh i membranakh éritrotsitov intaktnykh zhivotnykh i pri stresse.

In activity the comparative analysis of metabolic effects delta--sleep inducing peptide (DSIP) in tissues and erythrocytes of intact rats and under cold stress is conducted. The regulation effect of DSIP in attitude of free radical processes will be realised through modulation the prooxidant--antioxidant balance: both for intact animal, and at stress. Exogenous DSIP increases the antioxidant system activity in tissues of brain, liver and blood in standard conditions and under cold stress. The anti-stress effect of DSIP is directed as on increase of power endogenic enzymatic antioxidant system activity, specially glutathione peroxidase activity, and not enzymatic of antioxidant protection. The DSIP renders different influence on activity of prooxidant enzymes: for intact animal boosts the myeloperoxidase activity in blood neutrophils, not rendering essential influencing on the xanthine oxidase activity in tissues of brain, liver and activates the myeloperoxidase activity, depresses the xanthine oxidase activity for rats at stress. The membranotropic effect of DSIP in the norm and under stress is connected to increase of stability of protein--lipid interplays. The membranostabilizing effect of DSIP in conditions of stress is characterized decrease of polarity of lipid phase and negative surface charge of erythrocyte membranes, modified in course of lipid peroxidation.

[Pharmacological efficacy of delta sleep-inducing peptide in experimental acute pancreatitis]. / Farmakologicheskaia éffektivnost' del'ta-son indutsiruiushchego peptida pri éksperimental'nom ostrom pankreatite.

The development of experimental acute pancreatitis (EOP) in rats is accompanied by (i) intensification of the lipid peroxidation (LPO) process and the accumulation of malonic dialdehyde (MDA, an LPO product) in the tissues of pancreas, liver, and kidney and in the blood serum, (ii) destabilization of membranes and reduction of the osmotic resistance of erythrocytes (ORE), (iii) increase in the concentration of extracorpuscular hemoglobin (ECH) and medium-molecular-weight molecules (MWM) in the blood serum, and intensification of protein autolysis in tissues. Preliminary triple intraperitoneal administration of a delta-sleep-inducing peptide (DSIP) in a dose of 12 micrograms/100 g body weight to the test rats with EOP stabilized LPO, improved the erythrocyte membrane structure, reduced the MDA level in tissues and blood serum, increased ORE, reduced the ECH and MWM level in the blood, and decreased the protein autolysis rate in tissues.

Regulation of free radical processes by delta-sleep inducing peptide in rat tissues under cold stress.

An intraperitoneal injection of an exogenous delta-sleep inducing peptide (DSIP) at a dose of 12 microg/100 g body weight shifted the prooxidant-antioxidant balance of free radical process (FRP) in tissues and erythrocytes of rats: the activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) and the concentrations of antioxidants (reduced glutathione in particular) increased. The DSIP stimulated the myeloperoxidase activity in blood neutrophils and had no effect on the activity of xanthine oxidase, a prooxidant enzyme, in the brain and liver. Cold stress displaced the prooxidant-antioxidant balance by increasing the xanthine oxidase activity in tissues and decreasing the myeloperoxidase activity in blood neutrophils; it also inhibited the enzyme antioxidant activities in tissues and erythrocytes that was neutralized by an increased ceruloplasmin activity in blood plasma and by an elevated level of antioxidants in rat blood and tissues. Preliminary administration of DSIP to animals exposed to cold stress restored the prooxidant-antioxidant balance: it normalized the myeloperoxidase activity in blood neutrophils, decreased the xanthine oxidase activity, and increased the activity of antioxidant enzymes in tissues and erythrocytes restoring the antioxidant level. The molecular regulation mechanism of free radical processes by DSIP in tissues under stressful conditions is discussed.

The effects of delta sleep-inducing peptide on the intensity of lipid peroxidation and xanthine oxidase activity in rat tissues during cold stress.

Exogenous delta sleep-inducing peptide given i.p. to intact rats at a dose of 12 microg/100 g decreased the levels of diene conjugates and Schiff bases in liver and brain tissues and had no effect on xanthine oxidase activity in these tissues. Cold stress was accompanied by increases in xanthine oxidase activity in rat liver and brain, with a consequent accumulation of diene conjugates and Schiff bases, as compared with intact animals. Preliminary administration of delta sleep-inducing peptide before three days of cold stress led to decreases in xanthine oxidase activity and lipid peroxidation products in the liver and brain, as compared with values in stressed rats. The protective effect of delta sleep-inducing peptide in stress is discussed.

[Regulatory effect of delta sleep-inducing peptide on the activity of antioxidant enzymes in erythrocytes and tissues of rats during cold stress]. / Regulitornoe vliianie del'ta-son indutsiruiushchego peptida na aktivnost' antioksidantnykh fermentov v éritrotsitakh i tkaniakh krys pri kholodovom stresse.

Antioxidant system's state of erythrocytes and tissues in rats under normal and cold stress conditions was studied. Intraperitoneal injection of exogenic DSIP at the dose of 12 mkg/100 g body weight both, to intact and to cold-exposed animals results in the increase of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase activities and concentration of glutathione in red blood cells, liver and brain.

[Effect of delta sleep-inducing peptide on lipid peroxidation and xanthine oxidase activity in rat tissues during cold stress]. / Vliianie del'ta-son indutsiruiushchego peptida na intensivnost' lipopereokisleniia i aktivnost' ksantinoksidazy v tkaniakh krys pri kholodovom stresse.

I. p. administration of exogenous delta-sleep-inducing peptide (DSIP) decreased the amount of diene conjugates and Schiff bases in the liver and brain in rats. The xanthine oxidase activity, at that, did not change. Cold stress enhanced the xanthine oxidase activity well as the amount of diene conjugates and Schiff bases. Preliminary administration of the delta-sleep-inducing peptide to cold-exposed animals diminished the xanthine oxidase activity and lipid peroxidation in the liver and brain. Protective effects of the DSIP under stress is discussed.