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Biomedical subjects

N V Kost

Publications and source records attributed to N V Kost.

At least 19 recordsLinked to original sources
PubMed2005

Reactions between beta-casomorphins-7 and 5-HT2-serotonin receptors.

Radioreceptor analysis showed that human beta-casomorphin-7 displaced 3H-spiperone from 5-HT2-serotonin receptors of the rat cerebral frontal cortex: EC50 8 +/- 1 microM. Human and bovine beta-casomorphin-7 dose-dependently blocked serotonin-induced human platelet aggregation: IC50 5 +/- 1 and 20 +/- 4 microM, respectively. It was proved that beta-casomorphins-7 act as 5-HT2-serotonin receptor antagonists; one of the mechanisms of their biological effects is presumably associated with modulation of the serotoninergic system.

Animals↗
PubMed2004

Half-life of leu-enkephalin in the serum of infants of the first year of life on different types of feeding: relationship with temperament.

The half-life of leu-enkephalin in the serum of infants aged under 1 year is significantly shorter than in adults. In girls leu-enkephalin half-life is significantly longer than in boys. The half-life of leu-enkephalin is different in infants on breast and formula feeding. Nine characteristics of temperament in infants of the first year of life were determined using EITQ and ITQ questionnaires. Serum leu-enkephalin half-life directly correlated with temperament characteristics (activity, perception, threshold), but not with the level psychomotor development.

Adult↗
PubMed2002

Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions.

Comparative study of plasma activities of enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions revealed significant differences between intact BALB/c and C57Bl/6 mice by the half-life of plasma leu-enkephalin. Selank in a dose of 100 micrograms/kg produced an anxiolytic effect in the open-field test and increased the half-life of plasma leu-enkephalin in BALB/c mice, but had no effect on behavioral reactions and enkephalinase activities in C57Bl/6 mice. Our results suggest that anxiolytic activity of Selank is associated with inhibition of enkephalin-degrading enzymes.

Animals↗
PubMed2001

Identification of delta- and mu-type opioid receptors on human and murine dendritic cells.

The purpose of this study was to evaluate mu- and delta-opioid receptors (OR) on human and murine dendritic cells (DC). Expression of mu- and delta-OR mRNA on DC was demonstrated by RT-PCR. The immunocytochemical and Western blot analyses revealed the expression of OR protein in DC. Radioreceptor assay demonstrated the specific saturated temperature-dependent binding of [3H]-labeled opioid ligand on DC and B(max)=2.8+/-0.3 fmol/10(6) cells and K(D)=4.8+/-1.0 nM were calculated by a Scatchard analysis. Finally, OR ligands DADLE and DAGO dose-dependently modulated the capacity of DC to induce T cell proliferation in an MLR assay. Importantly, expression of functional OR on DC was significantly increased upon TNF-alpha-induced DC maturation. Thus, these data suggest a new mechanism of opioid-dependent neuroendocrine immunomodulation.

Animals↗
PubMed2001

The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity.

Examination of patients with various forms of anxiety and phobic disorders (according to DSM-4 criteria) demonstrated a considerable shortening of enkephalin half-life and reduced total enkephalinase activity in the blood during generalized anxiety, but not during panic disorders and agoraphobia. This was probably related to low blood concentration of endogenous inhibitors of enkephalin-degrading enzymes in patients with generalized anxiety disorders. Heptapeptide Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro), which attenuates behavioral anxiety reactions and does not cause side effects typical of most anxiolytics, dose-dependently inhibited enzymatic hydrolysis of plasma enkephalin (IC50 15 microM). Selank was more potent than peptidase inhibitors bacitracin and puromycin in inhibiting enkephalinases. These results suggest that high efficiency of Selank in the therapy of anxiety and phobic disorders, including generalized anxiety, is due to its ability to inhibit enkephalin hydrolysis.

Anti-Anxiety Agents↗
PubMed2000

[Solid phase catalytic hydrogen isotope exchange in dalargin].

A [3H]Dalargin preparation with a molar radioactivity of 52 Ci/mmol was obtained by the high temperature solid-state catalytic isotope exchange (HSCIE) of tritium for hydrogen at 150 degrees C. This tritium-labeled peptide was shown to completely retain its biological activity in the test of binding to opioid receptors from rat brain. The dissociation constant of the Dalargin-opioid receptor complex was found to be 4.3 nM. The dependencies of the chemical yield and the molar radioactivity on the reaction time and temperature of HSCIE were determined. The activation energy of the HSCIE reaction for the peptide was calculated to be 32 kcal/mol. The amino acid analysis showed that tritium is distributed between all the amino acid residues of [3H]Dalargin at the HSCIE reaction, with the temperature growth significantly increasing the total tritium incorporation and, especially, enhancing the radioactivity incorporation into aromatic residues.

Animals↗
PubMed1986

[Effect of beta-endorphin and myelopeptides on the cAMP level and proliferation of lymphocytes in vitro].

Beta-endorphin (10(-11)-10(-9) M) has been shown to induce naloxone-independent depression of the proliferative activity of human peripheral lymphocytes (HL), stimulated by pokeweed mitogen without affecting PHA-stimulated HL proliferation. Beta-endorphin (10(-10)-10(-7) M) also caused changes in HL cAMP level, that were blocked by naloxone. Marked individual sensitivity to beta-endorphin effects has been noted. It has been also shown that a bone marrow preparation, stimulating antibody production (myelopeptides), causes naloxone-independent depression in the proliferative activity of HL, stimulated by PHA and pokeweed mitogen, as well as naloxone-blocked decrease in cAMP HL level. It has been concluded that beta-endorphin interacts with several types of opiate lymphocyte receptors and that opioids, contained in myelopeptides, are involved in the realization of myelopeptide effect on lymphocytes.

Adult↗
PubMed1983

[Opiate activity of a bone marrow humoral factor which stimulates antibody production].

The radioceptor method was used to demonstrate that humoral factor of the bone marrow, a stimulant of antibody production (SAP), contains substances that competitively remove 3H-morphine and 3H-met-enkephalin from opiate receptors of the rat brain, and 3H-met-enkephalin from specific binding sites on human lymphocytes. Comparison of the magnitudes EC50 SAP obtained during the removal of labeled opiates allows a suggestion to be made that opiates contained by the preparation under study have a greater capability to interact with delta-type opiate receptors rather than with those of the mu-type.

Animals↗
PubMed1982

[Reaction between endogenous opiates and human peripheral blood lymphocytes].

The radioreceptor method and determination of the content of cAMP in lymphocytes were used to study the interplay of met-enkephalin with human peripheral blood lymphocytes. The characteristics of specific binding of endogenous opiate with the cells, as well s a decrease in the activity of lymphocyte adenylate cyclase observed under the effect of met-enkephalin proved the presence of a specific interplay between the physiological concentrations of the opiate with lymphocytes. It is suggested that it is determined by the existence of two parallel mechanisms: a process having some features in common with the receptor binding and limited transport of the opiate inside the cell.

Adenylyl Cyclase Inhibitors↗
PubMed1980

[Immobilized luciferase from the fireflies Luciola mingrelica. Changes in the pH-dependence of the enzyme catalytic activity and stability during its immobilization on various polysaccharide carriers].

The luciferase from the fireflies luciola mingrelica was immobilized on different CNBr-activated polysaccharide carriers, e. g. Sepharose, Ultrodex, cellophane, Ultrogel. The catalytic activity and the inactivation rate constants of the soluble and immobilized enzyme at 25 degrees (pH 6.0--9.0) were determined. During immobilization on Sepharose the pH profile of activity shifts towards lower pH values, while upon immobilization on Ultrogel and Ultrodex it is considerably broadened. Immobilization on Ultrogel and Ultrodex results in a 3--100 -fold stabilization of the enzyme (pH less than 7.5). whereas the stability of luciferase immobilized on Sepharose and cellophane within the same pH range is 10--1000 times higher than that of the soluble enzyme. It was shown that inactivation of luciferase immobilized on Sepharose and cellophane is limited by oxidation of the SH-groups of the enzyme and is inhibited by dithiothreitol. The inactivation of luciferase immobilized on Ultrogel and Ultrodex and that of soluble enzyme is not limited by oxidation of the SH-groups.

Animals↗
PubMedDate not supplied

[Semax and selank inhibit the enkephalin-degrading enzymes from human serum]].

A dose-dependent effect of synthetic heptapeptides Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) on the enkephalin-degrading enzymes of human serum was demonstrated. The inhibitory effects of Semax (IC50 10 microM) and Selank (IC50 20 microM) are more pronounced than those of puromycin (IC50 10 mM), bacitracin, and some other inhibitors of peptidases. Beside the heptapeptides, their pentapeptide fragments also possessed an inhibitory effect; tri-, tetra-, and hexapeptide fragments did not display such an effect. As the above enzymes take part in degradation of not only enkephalins but also other regulatory peptides, it can be assumed that one of the mechanisms of biological activity of Semax and Selank is related to this inhibitory activity of theirs.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Leu-enkephalin homogeneously labeled with tritium in studying the Selank inhibiting effect on the enkephalin-degrading enzymes of human plasma].

A method of analysis of enkephalinase activity in blood plasma based on the application of Leu-enkephalin generally labeled with tritium at all its amino acid residues was developed. The method allows the simultaneous estimation of activity of several peptidases in microquantities of tissues. [G-3H]Leu-enkephalin was prepared by the method of solid phase catalytic isotope exchange (120 Ci/mmol) and subjected to proteolysis by the treatment with blood plasma. The resulting radioactive metabolites were separated by HPLC in the presence of the mixture of unlabeled fragments of Leu-enkephalin as internal standards. It was shown that aminopeptidases, dipeptidylaminopeptidases, and dipeptidylcarboxypeptidases respond for approximately 80%, 2%, and 10% of the total enzymatic activity, respectively. The new pathway of degradation of Leu-enkephalin by carboxypeptidase that provides for approximately 6% of the total enkephalin-degrading activity was discovered. Bestatin was shown to predominantly inhibit aminopeptidases and carboxypeptidases, whereas Selank is more specific for carboxypeptidases and dicarboxypeptidases. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Aminopeptidases↗
PubMedDate not supplied

[Effect of new peptide bioregulators livagen and epitalon on enkephalin-degrading enzymes in human serum].

The effect of new peptide bioregulators--Livagen (Lys-Glu-Asp-Ala) and Epitalon (Ala-Glu-Asp-Gly)--on endogenous opioid system was studied, particularly, their ability to change the activity of enkephalin-degrading enzymes from serum and interact with opioid receptors of the brain membrane fraction. Enkephalinase activity was assayed in vitro by the rate of 3H-Leu-enkephalin hydrolysis in the presence of the tested peptides. Livagen and Epitalon inhibited enkephalin-degrading enzymes from human serum. Livagen proved to be more efficient also as compared to well-known peptidase inhibitors such as puromycin, leupeptin, and D-PAM. The dose-inhibitory effect curves for Livagen and Epitalon were plotted; their IC50 equaled 20 and 500 microM, respectively. The interaction between the peptides and opioid receptors was estimated using a radioreceptor method with [3H][D-Ala2, D-Leu5]-enkephalin. No interaction was observed between the tested peptides and mu- or delta-opioid receptors of the membrane fraction from the rat brain.

Animals↗