Entity

Time filter

Source Type


Dvoretsky A.I.,Oles Honchar Dnepropetrovsk National University | Shainskaya A.M.,Weizmann Institute in Rehovot | Ayrapetyan S.N.,Chair Life science International Postgraduate Educational Center
Environmentalist | Year: 2012

Although the high sensitivity of the Na/K pump in cell membrane to ionizing radiation is well known in literature, the individual role of different isoforms of pump in determination of its radio-sensitivity is not clear yet. This is the subject of the present investigation. Using isotope, electro-physiological and enzymological methods, the effect of γ-ionizing radiation on cell membrane voltage-current characteristics, acetylcholine-induced membrane current, 22Na + and 45Ca 2+ exchange between cells and bathing solution, Na+K +-ATPase activity, dose-dependent ouabain binding with cell membrane, intracellular cAMP and membrane phosphorylation in snail neurons were studied. The changes in neurons as a result of 30-min γ-radiation exposure of snails to 5.16 Ci/kg at the end of the first 30 min of post-radiation period were as follows: the increase in membrane ionic conductance reversed the ouabain sensitivity of acetylcholine-induced currents, stimulation of 22Na + and 45Ca 2+ uptakes, inhibition of Na/K pump, activation Na/Ca exchange in reversed mode, increase in ouabain binding with high-affinity α 3 and decrease with α 2 middle-affinity receptors, decrease in intracellular cAMP content and membrane dephosphorylation. On the basis of the obtained data, it is suggested that both α 3 and α 2 catalytic subunits of Na ++K +-ATPase serve primary membrane sensors through the activation of which the biological effect of γ-radiation on neurons is realized. The IR has activation effects on α 3-dependent Na +/Ca 2+ exchange in forward and its inactivation on α 2-dependent reverse modes. © 2012 Springer Science+Business Media, LLC. Source


Ayrapetyan S.,Chair Life science International Postgraduate Educational Center
Environmentalist | Year: 2012

At present, when the technological progress brings progressive increase in environmental pollutions by different chemical and physical (ionizing and non-ionizing radiations) factors, the detection of the safety of environmental medium from the point of public health is one of the fundamental problems of modern Life Sciences. This problem has especially disquieting character after the Chernobyl and Japan nuclear catastrophes, when the level of background ionizing radiation and chemical pollutions of environmental medium of the number of world's regions are increased beyond safety doses. As the biological effect of weak environmental factors have nonlinear dose-dependent character, besides its thermodynamic characteristics it depends also on environmental composition and initial state of organism. Therefore, the current policy of World Health Organization and other international organizations whose mission is to establish safety standards for environmental pollutions by chemical and physical factors, based only on the their concentration or energy absorption rate by organism cannot be considered as adequate. It is suggested that the biological marker having universal sensitivity to different factors and determining the functional state of organisms could be used for estimation of the safety doses of environmental factors on organism. In present review are presented the data consisting of the hypothesis according to which the Na/K pump and Na/Ca-controlling cell hydration could serve as a universal and extra-sensitive cellular marker for detection of hazardous effect of environmental pollutions. © 2012 Springer Science+Business Media, LLC. Source


Martirosyan V.,Chair Life science International Postgraduate Educational Center | Moosavi E.,Chair Life science International Postgraduate Educational Center | Moosavi E.,Babol University of Medical Sciences | Ayrapetyan S.,Chair Life science International Postgraduate Educational Center
World Journal of Microbiology and Biotechnology | Year: 2011

The supercritical concentration of CO2 (SCCO2) and a high concentration (3.0%) of molecules of hydrogen peroxide (H2O2) are currently being used as antiseptic and antibacterial agents. The fact that low concentrations of CO2 have an activation effect on functional activity of microbes allows us to predict that CO2 could elevate the toxic effect of H2O2 on cells. To check this hypothesis the dependency of the toxic effect of H2O2 on wild type of Escherichia coliK-12 on soluble concentration of CO2 in culture media was studied. The obtained data show that culture media enriched with CO2 leads to the increase of toxic effect of H2O2 on microbes at both cases when pH is constant and when it changes. So CO2 in non-supercritical concentration could elevate the toxic effect of H2O2 on microbes by the activation of the metabolic processes in microbes. During the experiments we used classical microbiological methods (indirect viable cell counts or counting colony forming units (CFUs)), as well as the method of measuring hydrogen peroxide content in aqueous solution by means of enhanced chemiluminescence method in a peroxidase-luminol-p-iodophenol system. This discovery is concerning to use CO2/H2O2 combination system, which could have implication in the inhibition of growth of microbes in water and the microbiological monitoring of water could provide valuable information for managing the health of exhibition of aqua ecosystems. © 2010 Springer Science+Business Media B.V. Source


Narinyan L.Y.,Chair Life science International Postgraduate Educational Center | Ayrapetyan G.S.,Chair Life science International Postgraduate Educational Center | Ayrapetyan S.N.,Chair Life science International Postgraduate Educational Center
Bioelectromagnetics | Year: 2013

In our previous work we have shown that the age-dependent decrease in the magnetosensitivity of heart muscle hydration is accompanied by a dysfunction of the Na+/K+ pump. The reciprocal relation between the Na+/K+ pump and Na+/Ca2+ exchange in development was suggested as a possible pathway for the age-dependent decrease in the magnetosensitivity of heart muscle hydration (water content). Because high and low affinity ouabain receptors in cell membranes are involved in Na+/Ca2+ exchange and Na+/K+ pump functions, respectively, the effect of a 0.2T static magnetic field (SMF) on dose-dependent, ouabain-induced hydration and [3H]-ouabain binding with heart muscle tissues in young, adult and older rats was studied. Three populations of receptors in membranes with high (10-11-10-9M), middle (10-9-10-7M) and low (10-7-10-4M) affinity to [3H]-ouabain were distinguished, which had specific dose-dependent [3H]-ouabain binding kinetics and effects on muscle hydration. The magnetosensitivity of [3H]-ouabain binding kinetics with high affinity receptors was prominent in all the three age groups of animals, while with low affinity receptors it was more expressed only in the young group of animals. All three types of receptors that caused modulations of muscle hydration were age dependent and magnetosensitive. Based on the obtained data we came to the conclusion that heart muscle hydration in young animals is more magnetosensitive due to the intense expression of high affinity ouabain receptors, which declines with aging. Bioelectromagnetics 34:312-322, 2013. © 2012 Wiley Periodicals, Inc. Source


Narinyan L.,Chair Life science International Postgraduate Educational Center | Ayrapetyan G.,Chair Life science International Postgraduate Educational Center | Ayrapetyan S.,Chair Life science International Postgraduate Educational Center
Bioelectromagnetics | Year: 2012

The reason for hyper magnetosensitivity of young animals compared to older ones remains unclear. It has been suggested that age-induced tissue dehydration (decreased water content) could be a basis for the aging-related decrease in the organism's magnetosensitivity. To test this hypothesis, the effect of a 0.2T static magnetic field (SMF) exposure on heart muscle hydration in three age groups of rats (young, adult, and older) was studied, with and without ouabain poisoning. The SMF exposure resulted in heart muscle dehydration of young (21%) and adult (6.2%) rats but had no effect on older animals. In young animals without ouabin poisoning, SMF exposure caused dehydration of the heart muscle while in the ouabain-poisoned animals it led to hydration (29.6%). These hydration effects were more pronounced in young animals than in adult and older animals. The increased hydration (5.7%) of heart muscles in older animals was evoked by providing distilled water for seven days, which elevated (by 12%) the SMF-induced heart muscle hydration effect. These results suggest that the hyper magnetosensitivity of the young heart muscle and the lower sensitivity of older animals are due to initial high (83.5%) and low (75.3%) tissue hydration levels, respectively. Therefore, the age-induced decrease in the magnetosensitivity of heart muscle is likely to be a result of Na +/K + pump dysfunction. © 2012 Wiley Periodicals, Inc. Source

Discover hidden collaborations