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V I Korol'kov

Publications and source records attributed to V I Korol'kov.

At least 19 recordsLinked to original sources
PubMed2005

Effects of the C-terminal peptide of the alphaS subunit of the G protein on the regulation of adenylyl cyclase and protein kinase A activities by biogenic amines and glucagon in mollusk and rat muscles.

The C-terminal parts of the a subunits of heteromeric G proteins play an important role in the functional linkage of G proteins with receptors of the serpentine type. The present report describes studies of the effects of the C-terminal octapeptide 387-394 of the alphaS subunit of the mammalian G protein on the transmission of the hormonal signal via the hormone-sensitive adenylyl cyclase signal system, whose major components are receptors of the serpentine type, G proteins, and the enzymes adenylyl cyclase and protein kinase A. The peptide synthesized here, 387-394 amide (10(-7) - 10(-4) M), dose-dependently decreased adenylyl cyclase and protein kinase A activities stimulated by serotonin and glucagon in smooth muscle from the freshwater bivalve mollusk Anodonta cygnea and by the beta agonist isoproterenol in rat skeletal muscle. At a concentration as low as 10(-7) M, the peptide released potentiation of the stimulatory effects of hormones on adenylyl cyclase activity due to the non-hydrolyzable guanine nucleotide analog Gpp[NH]p. At the same time, it had almost no effect on the stimulation of adenylyl cyclase activity by non-hormonal agents (NaF, Gpp[NH]p, and forskolin). The inhibitory effects of hormones on adenylyl cyclase and protein kinase A activities persisted in the presence of the peptide. Our data demonstrate the importance of the C-terminal part of the alphaS subunit of the stimulatory G protein for its functional linkage with receptors of the serpentine type and throw light on the molecular mechanisms of the interactions between G proteins and receptors.

Adenylyl Cyclases↗
PubMed2005

[Inguinal lymph nodes of monkeys subjected to 8-days-long immersion in water].

The morphometric study of cytoarchitecture of the structural and functional components of lymph nodes of male monkeys (Macaca mulatta) aged 4-5 years was performed after 8-days-long immersion in water. Activation of lymphocyte mitotic activity in lymphoid nodules (B-dependent zones) was demonstrated in association with an accumulation of small lymphocytes in them and an increase of macrophage reaction. Accumulation of mature forms of plasma cells was detected in all the structures of lymph nodes. It was also found that 8-days-long immersion in water resulted in remodeling of the vessels of lymph node microcirculatory bed, which was accompanied by changes of the endothelium in blood vessel wall and by disturbances of lymph drainage, that lead to accumulation of lymphocytes in lymph node sinuses.

Animals↗
PubMed2003

[The effect of microgravity and head down immobilization on hemopoiesis in primates].

Objects of the investigation were peripheral blood and bone marrow cytology in 6 primates during readaptation following the 2-wk. space flights (SF) aboard biosatellites BION-9, 10 and 11, and ground-based simulations of 17-d sitting in the chairs of the Bios-primat capsule (4 primates) and 4-wk. head-down immobilization (-5 degrees, 12 primates). On completion of each of the three experiments, the hemopoietic system was characterized by a distinct nonspecific stress-reaction, i.e. neutrophilous leukocytosis against reductions of the lymphocyte and eosinophil counts. After SF and HD immobilization, the blood profile carried signs of a specific reaction which consisted of a hemoconcentration (hematocrit and hemoglobin) reduction during early readaptation and recovery as a result of erythropoiesis activation due to, primarily, blood redistribution and a decreased weight-bearing load. The specific reactions to HD immobilization were less significant and did not reveal themselves at all in the chaired primates.

Animals↗
PubMed2003

[Effect of C-terminal peptide of G-protein alfa(s)-subunit on regulation of adenylate cyclase and protein kinase A activities by biogenic amines and glucagon in mollusc and rat muscles].

The peptide synthesised by us: 387-394-amide (10(-7)-10(-4) M), in a dose dependent manner decreases activities of adenyl cyclase and proteinkinase A evoked by serotonine and glucagon in smooth muscles of the freshwater bivalve mollusc Anodonta cygnea and that evoked by beta-agonist isoproterenol--in the rat skeletal muscles. Even in concentration 10(-7) M, the peptide completely eliminates potentiation of the hormones' stimulating effect on adenylyl cyclase activity with the non-hydrolizable analogue of guanine nucleotides (Gpp[NH]p). At the same time, the peptide does not affect stimulation of the adenylyl cyclase activity with non-hormonal agents (NaF, Gpp[NH]p and forkolin). In the presence of the peptide, inhibiting effects of the hormones on activities of adenylyl cyclase and protein kinase A will be preserved. The findings reveal the importance of the G-protein alpha s-subunit's C-terminal regional of a stimulating type for its functional coupling with receptors of a serpentine type, and elucidate the molecular mechanisms of interaction between the G-protein and the receptor.

Adenylyl Cyclase Inhibitors↗
PubMed2003

[Psychosomatic evaluation of primates with the use of a psychomotor testing system].

The higher nervous system reactions of rhesus monkeys to the head-down tilt (HDT, 28 d, -5 degrees) and preventive centrifugation were evaluated with the use of a computerized psychological testing system (PTS). Prior to HDT, the primates elaborated conditioned instrumental food-obtaining reflexes by playing computer games. Drilled to perform PTS tests to the best of their ability, the animals were to fulfill two PTS tests of increasing complexity in HDT. Test results were used to determine the dynamics of primates' cognitive function and the psychological state. The investigation consisted of two series with two groups of monkeys in each series. Twelve animals of each group (10 had skill in performing the PTS tests) were distributed into 2 subgroups. Every other day one of the subgroups was exposed to centrifugation at 1 to 2.5 g. In the first series, 10 monkeys worked on the simplest test, i.e. spotting a static object. All animals showed interest in the computer game, and played a lot and successfully during HDT. In the second series, the animals were challenged with a more difficult test of following a moving object with the cursor. Based on the analysis of experimental data, a significant variability in achievement and emotional behavior of the primates should be attributed to different types of the nervous system.

Affect↗
PubMed2002

[Basic results of the investigation of the effects of antiorthostatic hypokinesia on the functioning of various systems in monkey's organism].

Presented are results of comprehensive studies of functioning various body systems of Macaca mulatta after 4 weeks in antiorthostatic hypokinesia (head-down tilting, HDT). HDT deteriorated monkeys' tolerance of +Gz, altered the higher nervous functioning, and brought about serious disorders in coordination and locomotion. It also impacted energy metabolism, reduced hydration of organism, caused various shifts in the neuroendocrine system, circulation and its controls, and protein, carbohydrate and mineral metabolism. HDT resulted in inhibition of the lymphoid activity of structural components of the lymph nodes, changes in the musculoskeletal apparatus of the lower limbs, atrophic developments in the iliac crest spongiosis, and reduction of the oxidative potential of fibers in the crus extensors, and the number of capillaries in a fiber. These observations are ascribed to redistribution of the body fluids, hypokinesia per se and absence of the effects of support. This HDT model can be applied to monkeys for studying processes of the hypokinetic syndrome and developing countermeasures.

Animals↗
PubMed2001

[Effect of synthetic cationic peptides on activation of the adenylyl cyclase signaling system by biogenic amines in muscle tissue of molluscs and rats].

The hormone-sensitive adenylyl cyclase signaling system (ACS), made of serpentine receptor, heterotrimeric G-protein and enzyme adenylyl cyclase (AC), regulates a wide spectrum of growth and metabolic processes in the cell. Molecular mechanisms of functional coupling of ACS components still remain obscure. We examined the influence of synthetic cationic peptides Ac-Ala-His(Ala)2-His-Ala-NH2 (I), Ac-Ala-His-(Ala)3-His-(Ala)2-His-Ala-NH2 (II), and Ac-(Pro)2-His-(Ala)2-His-(Ala)3-His-(Ala)2-His-Ala-NH2 (III) on the basal AC activity and that stimulated by nonhormonal (NaF) and hormonal reagents (serotonin--molluscs, beta-isoproterenol--rats) in smooth muscles of the freshwater bivalve molluscs Anodonta cygnea and in skeletal muscles of rats. Peptides II and III (the latter more effective) were shown to decrease hormone-stimulated AC activity in both tissues, in a dose-dependent manner. Peptide III strongly reduced NaF stimulating effect to AC, which suggests the involvement of this peptide in the functional coupling of both receptors with G-proteins, and of G-proteins with AC. A correlation was found between the efficacy of peptide action on the functional activity of ACS components and peptide length. As shown by IR-spectroscopy, in water all peptides can form helical structures. However, alpha-helicity of peptides I and II was higher than that of peptide III, which does not conform to a power series in efficacy of these peptides. Thus, it is the length of cationic peptides that plays a key role in hormonal regulation of the functional activity of ACS, especially on the step of receptor-G-protein coupling.

Adenylyl Cyclases↗
PubMed2001

[Structural and metabolic characteristics of m. vastus lateralis of monkeys during 30-day hypokinesia: effects of prophylactic Gz-accelerations].

Studies of m. vastus lateralis in Rhesus monkeys exposed to weightlessness on board of the Russian biosatellites showed the profound changes of the muscle structural and metabolic profile. It is known that exposure to head-down tilt berets (BR) induces the similar changes though not so pronounced. It is supposed that the artificial gravity application is one of the promising countermeasure means purposed to prevent from the unfavourable effects of exposure to weightlessness. The present work was aimed to study the effects of the artificial gravity on structural and metabolic characteristics of hind-limb muscle in monkeys exposed to BR. 11 monkeys were subjected to 30 day 6 head down tilt BR.5 animals of them (group BR + Gz) were exposed also to daily rotation on the centrifuge (1.4 G for 5-20 min), the other animals (BR) were under only pure BR during the study. In BR animals the m. vastus lateralis slow-twitch (ST) and fast-twitch (FT) fiber size decreased by 25.4% and 12.7% respectively. In group BR + Gz the ST and FT fiber cross-sectional area was reduced by 18.7% and 8.1% respectively. The area percentage of the connective tissue compartment in BR animals increased from 4.6% to 6.8%. Capillary per fibre ratio was reduced by 9.6% and 8.6% in BR and BR + Gz monkeys respectively. The less pronounced level of capillary reduction as compared to level of fibre size decrease led to the increase of the capillary density by 13% in BR group, and no change in BR + Gz one. No changes in succinate dehydrogenase (SDH) activity were revealed in fibres of BR animals (this phenomenon may be the consequence of the proportional decrease of the oxidative potential and fibre size). In BR + Gz monkeys the SDH activity were found to be significantly elevated by 22.2% and 28.6% in ST and FT fibres respectively. Thus the data obtained show that chronic application of Gz tends to diminish the intensity of structural and metabolic changes in skeletal muscles under simulated microgravity.

Acceleration↗
PubMed1998

[The effect of a two-week anti-orthostatic hypokinesia on the cardiac function and on the latter's regulation in monkeys].

Investigated were the effects of 2-week exposure of four Macaca mulattas to the head-end tilted downward at 10 degrees on contractility of the left myocardium and its controls basing on the data of functional loading tests on the tilting table and at two regimes of centrifugation. The experiment included registration of the left heart pressure, volumetric blood flow in the aorta, and EKG in order to determine stroke volume, maximal isovolumetric pressure, end-systolic and end-diastolic pressures, maximal contraction and relaxation velocities, end-systolic myocardial elasticity, and a constant of the isovolumetric relaxation. As was stated, HDT does not impair contractility of the left myocardium; however, sensitivity of the HR baroreflex control wakens.

Animals↗
PubMed1998

[Carbohydrate adaptive substance for prophylaxis of immune disorders and correction of dysbacterioses].

Effects of a new preparation, adaptokhit, on the intestinal microbiocenosis and some parameters of immune resistance were studied in Macaque rhesus during 13-day hypokinesia. Experimental animals were given adaptokhit as an alimentary supplement preventing dysbiotic consequences of the microecologic unbalance due to motor restraint. Results of the investigation showed certain distinctions in the intestinal microflora in the experimental and control animals as early as on day three of the experiment. Intestinal microflora of the experimental primates who daily consumed adaptokhit at 50 mg/kg of the body remained stable throughout the period of observation. In contrast, in their controls lactoflora was found to decrease in parallel to the growth of opportunistically pathogenic endobacteria including representatives of Proteus and Clostridia sp., and development of dysbacteriosis of categories II and III. Besides, in the experimental animals adaptokhit prevented decline in the proliferative activity of lymphocytes further into adaptation. Also, at the final stage of observation following canceling the preparation there were signs of normalization of the allergologic status of primates in the experimental group. Therefore, adaptokhit can be used as an alimentary supplement to strengthen the colony resistance of animals in extreme conditions.

Animals↗
PubMed1996

[The indices of water-salt metabolism and of the endocrine status in monkeys after flights on the Kosmos biological satellites].

Findings of studying the indices of water-salt metabolism and endocrine status of monkeys after their exposure in the weightless environment onboard the biological satellites of Earth have revealed a change in the blood serum concentrations of electrolytes which is indicative of instability of the system responsible for maintenance of the fluid-mineral homeostasis during readaptation. Results of studying the endocrine status of monkeys infer alteration in calcium metabolism, i.e. decreased levels of parathyroid hormone, calcitonin and the transport form of vitamin D3.

Adaptation, Physiological↗
PubMed1995

[Intracranial pressure in monkeys during the flight of Cosmos-2229].

The paper contains data of the experiment aboard biosatellite Cosmos-2229 which embraced registration of the intracranial pressure (ICP) in primates during space flight. ICP exhibited a small increase (25-30%) comparing with mean values over 20 hours of the prelaunch period and did not go beyond the limits of physiological norm. In the second part of the flight, ICP tended to return to the preflight level. The ICP pulse wave pattern was considerably changed on account of the venous component on the initial days of orbiting and nearly assumed its preflight form further in flight. The diurnal ICP rhythm was found to be gradually altering in the course of the flight.

Animals↗
PubMed1994

[Intracranial pressure in monkeys under microgravity].

The results of measurement of the intracranial pressure (ICP) in monkeys on board of the biosatellite "Cosmos-2229" are presented. The ICP grew insignificantly in microgravity. The ICP pulse waveform changed significantly in the first day of the flight but returned to normalcy later.

Animals↗
PubMed1989

[Cyclic analogs of enkephalin with disulfide bridges between the second and fifth positions].

Biological activity of the enkephalin cyclic analogues with a disulphide bridge between second and fifth positions, and the dependence of the activity on the cycle size, disulfide bridge localization and configuration of the amino acid residues have been studied. The analogues were synthesized by chemical approach with the use of pentafluorophenyl esters. The cyclization was carried out at the C-terminal tetrapeptide stage by iodine in methanol after removing benzyl protecting groups from thiol groups of cysteine and homocysteine by sodium in liquid ammonia. The blocking activity in vitro (GPI and MVD tests) to the mu- and delta-receptors depends on cycle size, localization of disulphide bridge in the cycle, and amino acid configuration at second and fifth positions. Analogues with D-amino acids proved to be most active in vivo (analgesia, cataleptic activity, effect on frequency of heart contractions and body temperature). Conformational characteristics of enkephalin analogues were investigated by means of CD spectroscopy.

Amino Acid Sequence↗
PubMed1976

[Dynamics of the mass of the right ventricle of the heart and concentration of RNA in it during the process of "reverse" development of hypertrophy].

Experiments were conducted on male rats, 250-300 g in weight. Adaptation to high altitude hypoxia was created by placing the animals daily for 5 hours, into an altitude chamber, at an "altitude" of 6000 m. The degree of hypertrophy of the right ventricle and its RNA content was studied after 20 days of adaptation, as well as 2, 10, 20 and 40 days after cessation of hypoxia. Twenty days after the beginning of adaptation the muscle mass of the right ventricle the RNA concentration and amount in it was found to increase considerably. After cessation of hypoxia half of the acquired increase in the ventricle muscle mass was lost in 10 days, and half of the acquired increase in the RNA--as soon as in 2 days. Forty days after cessation of hypoxia the right ventricle mass and its RNA content in the adapted animals did not differ from the same indices in control rats.

Adaptation, Physiological↗