[The influence of dynorphin A (1-13) on lipid peroxidation and antioxidant enzymes activity in the immobilization stress of different duration].

It was revealed in experiments on rats, that selective agonist of opioid kappa-receptors dynorphin A (1-13) has expressed antioxidant action in immobilization stress of different duration. It manifests itself with the decreases of the content of lipid peroxidation metabolites in liver tissue. It was shown, that the effect of this peptide on the activity of antioxidant enzymes superoxiddismutase and catalase depends on the stress duration. The stimulatory influence of peptide on catalase activity was shown in the rats after 3-hours immobilization, but the analogue effect of dynorphin was less in the animals after 6-hours or 12-hours stress. The stimulatory action of dynorphin A (1-13) on the superoxiddismutase activity was established in the rats after 6-hours or 12-hours immobilization within the experiment period, but peptide had no effect in the rats after 3-hours stress.

[The influence of melatonin on the content of lipid peroxidation metabolites and antioxidant enzyme activity in the liver of rats after immobilization].

The modeling of acute immobilization stress caused the increase of the content of lipid peroxidation metabolites and the decrease of the activity of superoxiddismutase and catalase in liver tissue within 4 days after stress. Melatonin in dose 0.2 mg/kg had a weak antioxidant effect and increased superoxiddismutase activity. The injection of melatonin in dose 1.0 mg/kg caused the significant decrease of lipoperoxidation metabolites content in liver tissue 39 hours after stress. On fourth and seventh days of the experiment there were no differences in malonic dyaldehyde content between these animals and naive ones. The concentration of acylhydroperoxides was significantly less than in control and naive groups at these days. The activity of superoxiddismutase and catalase was significantly more than in control rats at the fourth day after stress.

[The influence of melatonin on lipid peroxidation and antioxidant enzymes activity during multiply repetitive stress actions].

It was established that the modeling of the repeated immobilization stress is accompanied by the increase of the content of lipid peroxidation metabolites and the decrease of antioxidant enzymes activity (superoxiddismutase and catalase) in both blood plasma and liver tissue. Intraperitoneal melatonin injections in the doses 0.2 or 1 mg/kg during 7 days cause the decrease of the content of lipid peroxidation metabolites in both blood plasma and liver tissue in animals after prolonged stress, as well as leads to the increase superoxiddismutase activity in both blood plasma and liver tissue in comparison with the control group. In liver tissue catalase activity increased after the melatonin application at both doses in comparison with control animals, but in plasma the same change was observed only after 1 mg/kg melatonin inject. The results of investigation confir- med the literature data about the antioxidant effects of melatonin and opened the perspectives of its using for the prevention of stress-induced organ injury.

[Lipid peroxidation in the immobilization stress of different duration].

It was demonstrated in experiments on rats, that increase of immobilization stress duration causes more prolonged activation of lipid peroxidation, however significant differences of both malonic dialdehyde and acylhydroperoxides content were not established in early period after stress in rats, which were exposed to the immobilization of different duration. It was shown, that increase of superoxiddismutase activity is observed in early period of 3-hour and 6-hour stress, but it was decreased in 12-hour immobilization. Catalase activity was decreased in 6-hour and 12-hour stress. These results confirm the literature data about dependence between the expression of stress manifestations and the strength and duration of stress factor action.

[Opioid peptides effect on lipid peroxidation in long-term stress].

It was shown in rats, that injection of opioid peptides (dynorphin A (1-13), DSLET and DAGO) decreased the stress-induced activation of lipid peroxidation in liver tissue and plasma. Dynorphin A (1-13) manifested the most expressed antioxidant effect in liver tissue. It not only decreased lipid peroxidation metabolites concentration, but also increased superoxiddismutase and catalase activity. Other peptides did not interfere enzyme activity. The use of DSLET or DAGO increased the superoxiddismutase plasma activity. Dynorphin A (1-13) injection increased catalase activity, but not superoxiddismutase. These effects could be explained by peculiarities of opioid receptors spread in liver tissue and stress-limiting action of peptides in entire organism.

[Effect of opiod peptides on free radical oxidation in a bone regenerate after fracture].

Opioid peptides (DSLET and DAGO) stimulating bone tissue regeneration were studied for effects on content of free radical products in regenerate tissue from the region of leg fracture in mice at various terms of reparative osteogenesis. These opioids reduce concentration of malonic dialdehyde and dienic conjugastes in bone for 10 days after fracture.

[Effect of opioid peptides on the repair regeneration of the bone tissue]. / Vliianie opioidnykh peptidov na reparativnuiu regeneratsiiu kostnoi tkani.

The study is made of the effects of selective agonists of opioid receptors (DAGO--the agonist of mu-receptors, DSLET--the agonist of delta-receptors, dynorphin A,I-13,--the agonist of kappa-receptors) on reparative osteogenesis in CBA mice. The drugs were injected intraperitoneally within 7 days after bone fracture in equimolar doses: DAGO--6.3 mcg/kg, DSLET--10 mcg/kg, dynorphin A (1-13)--20.2 mcg/kg. It was established that the use of DSLET and DAGO accelerates the development of newly-synthesized spongy bone tissue in the bone regenerate. This manifested with its early appearance (4 days after the fracture) as well as higher indices of specific volumes of bone tissue in the regenerate within the experiment (7, 10, 14 days after bone fracture) in comparison with the control animal group. Dynorphin A(1-13) had no influence on regenerate formation in our experiments.

[Effect of opioid peptides on proliferation and differentiation of skeletogenic cells of rabbit bone marrow in vitro]. / Izuchenie vliianiia opioidnykh peptidov na proliferatsiiu i differentsirovku skeletogennykh kletok kostnogo mozga krolika in vitro.

The influence of opioid peptides DSLET and DAGO in doses 10(-5), 10(-7) or 10(-10) mg per 1 ml of the medium on colony formation in the culture of stromal bone marrow fibroblast precursors was investigated 5. 10(-6) bone marrow cells were placed in plastic containers (Costar). 12 day old cell cultures were fixed with ethanol and stained with hematoxyline-eosin. Effectiveness of fibroblast colony formation (EFFC) was detected. Grown fibroblast colonies were stained after Gomory for alkaline phosphatase. Opioid peptides DSLET and DAGO in the used doses exerted no influence on EFFC and percentage phosphatase-positive colonies, which casts doubt on a presumable direct action of opioid peptides on stromal bone marrow cell-precursors. But it does not seem unlikely that opioid peptides may affect stromal bone marrow precursors of fibroblasts through the cell environment, particularly, via macrophages.

[Neurotropic effects of luliberin analog in rats with different sensitivity to ethanol]. / Neirotropnye éffekty analoga liuliberina u krys s razlichnoi chuvstvitel'nost'iu k étanolu.

Luliberin's analogue (surfagon) has been established to activate shock-induced aggression of short-sleeping (SS) and long-sleeping (LS) rats in painful stress. The using of the castration and hypophysectomy has proved this effect to result from the direct neurotropic action of peptide. It has been shown, that SS rats differ from LS ones by more expressed reducing of painful aggressive and reference reactions after castration and hypophysectomy as well as by definitive peculiarities of peptidergic effects of surfagon.

[The effect of leu-enkephalin and its synthetic analog on the behavior of rats with different sensitivities to ethanol]. / Vliianie lei-énkefalina i ego sinteticheskogo analoga na povedenie krys s razlichnoi chuvstvitel'nost'iu k étanolu.

Leu-enkephalin and its analogue N 171 increased the pain thresholds and reduced the affective aggression in unrestrained male rats. The N 171 manifested a greater analgesic and antiaggresiogenic effect, particularly in i.p. administration. Preliminary administration of peptides manifested a more obvious effect in alcohol-preferring rats under painful stress.