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Biomedical subjects

M R Shchurin

Publications and source records attributed to M R Shchurin.

9 recordsLinked to original sources
PubMed1994

[The effect of dalargin on the opioid and immune systems in patients with a depressive syndrome].

Depressed patients and healthy donors received dalargin. As shown by the radioreceptor test, the patients recovered normal quantitative and qualitative values of plasma opioid activity due to this drug which is a synthetic agonist of sigma-type opioid receptors. Lymphocyte proliferative activity (spontaneous and induced by polyclonal mitogens) was not significantly different in the test subjects versus the donors, though in vitro studies revealed multidirectional homeostatic effects of dalargin. It is shown that depressions are associated with defective relationships between functions of the immune and opioid system. Dalargin proved uneffective in the treatment of endogenic psychotic depressions, whereas in reactive neurotic depressions and psychosomatic abnormalities the drug is promising and needs further investigations.

Adult↗
PubMed1992

[The normalizing effect of dalargin on the glucocorticoid and opioid levels of the blood in CBA and C57Bl/6 mice undergoing footshock stress].

Radioreceptor investigations showed that it is impossible to interpret changes in the activity of opioid receptor ligands of mu and delta types in plasma of mice under footshock stress (FSS) as activation or depletion of opioid system (OS). There occurred qualitative changes characterized by interstrain differences (ID). These are also typical for dynamics of development of FSS effects on blood corticosterone levels. Administration of dalargin diminishes qualitative and quantitative changes in OS function at different periods after FSS preventing early rise of corticosterone levels after the exposure. In spite of common features in dalargin action on opioid and steroid metabolism in mice of both strains, ID are also present.

Animals↗
PubMed1991

[The effect of different methods of isolating thrombocytes on the surface structure and biochemical parameters of the serotonin system of these cells].

The method of platelets' isolation influences their morphofunctional state. The study of the surface structure of platelets with the method of scanning electron microscopy shows, that the nonactivated form of platelets is characterized for the cells, isolated by gel filtration, but platelets which are isolated by centrifugation are activated. Platelets' activation under centrifugation is shown to connect with the changes of biochemical parameters of platelet serotonin system: the increase of the velocity of the 3H-serotonin reuptake and of the 3H-imipramine specific binding.

Adult↗
PubMed1989

[A decrease in the content of immunoreactive alpha- and gamma-endorphins in the blood and the suppression of their hypersecretion under the influence of dexamethasone in emotional stress in monkeys].

Daily administration of 12 mg of dexamethasone to monkeys during 10 days resulted in decrease of the levels of alpha- and gamma-endorphins and cortisol 7 days after the first injection. The titers of these peptides in plasma of monkeys. exposed to two hours of immobilization stress were elevated twice above basal levels. The maximum elevation took place 6 hours after the beginning of immobilization. This effect wasn't detected in monkeys, which received 12 mg of dexamethasone during 10 days.

Acute Disease↗
PubMed1987

High- and low-affinity [3H]imipramine binding sites on human platelets: separate determination and involvement of sulphur-containing bonds.

We have confirmed the presence of two different classes of [3H]imipramine ([3H]IMI) binding sites on human platelets: high-affinity (Kd = 0.52 nM, Bmax = 1670 fmol/mg protein) and low-affinity (Kd = 101 nM, Bmax = 8,000 fmol/mg protein) binding sites. The high-affinity component of [3H]IMI binding can also be obtained separately as the difference between specific [3H]IMI binding in Na-containing and Li-containing incubation buffer. The low-affinity component can be obtained as the difference between [3H]IMI binding in 50 mM Tris-HCl, 5 mM KCl, 120 mM LiCl, (pH 7.5) in the absence and presence of 0.1 mM IMI. The chemical modification of SH groups was performed with Ellman's reagent (10 mM, 40 min at 23 degrees C). The high-affinity component of the binding was totally inhibited while the low-affinity component only decreased by 39%. No decrease in [3H]IMI specific binding was observed when the modification of SH groups was carried out in the presence of 1 microM IMI. The inhibition of high- and low-affinity [3H]IMI binding was reversible since it was completely restored by incubation of modified membranes with 1,4-dithioerythritol (DTE). The reduction of SS groups by DTE (10 mM, 1 h at 23 degrees C) in the intact membrane preparation produced an increase in total number of binding sites of the high-affinity component of [3H]IMI binding by 50%.

Adult↗
PubMed1986

[Effect ot thyroliberin on rat brain opiate receptors].

The ability of thyroliberin to interact with opiate receptors of the rat midbrain and hypothalamus has been studied. It was shown by competitive displacement analysis that thyroliberin did not replace labeled opioid peptides in opiate receptor binding sites when added in vitro at concentrations of up to 10(-5) M. The specific binding of opioid peptides was increased by 10-20% in the presence of 10(-7)-10(-6) M thyroliberin. This effect was, probably, due to the rise in the affinity of high-affinity opiate receptors. At the same time the affinity of low-affinity binding sites was decreased. It is suggested that the antagonistic properties of thyroliberin are mediated by the modulation of the binding characteristics of enkephalin-low-affinity opiate receptors.

Animals↗
PubMed1985

Thymus peptides interacting with opiate receptors.

The substances displacing labelled ligands from opiate receptors of the rat brain membrane fraction were found in the thymosin fraction 3 and acetoacid extract of the thymus by the radioreceptor assay. Comparison of the displacing activity of acetoacid extracts of perfused and non-perfused thymus and peripheral blood as well as an estimation of the blood content in the thymus allowed to conclude that blood does not participate in the ability of thymus preparations to bind to opiate receptors. On the basis of the enzymatic treatment data one can conclude that opiate receptor ligands present in thymus preparations are of peptide nature. The value of their sodium shift suggests that those peptides are partial agonists of morphine. The possible role of opioid peptides in the thymic endocrine function is discussed.

Animals↗