Victor V. Zhirnov
Institute of Bioorganic Chemistry and Petrochemistry, Ukraine
Title: Influence of low rate β-radiation (90Sr/90Y) on transmembrane electron transport in human erythrocytes
Biography
Biography: Victor V. Zhirnov
Abstract
Protection against the reactive species generated during oxidative stress is probably main role of transmembrane electron transport (tMET). Membrane redox systems transfer electrons across the plasma membrane, resulting in the net reduction of extracellular oxidants. The low rate ionizing radiation changes of spatial organization of lipid-protein complexes of erythrocyte membranes. It can induce fluctuating of activity membrane-bound proteins. Therefore influence of low dose rate ionizing radiation on tMET in human erythrocytes was studied.
Erythrocyte tMET activity was determined by using extracellular ferricyanide as an electron acceptor. Release of ferrocyanide was measured by formation of ferrous bathophenanthroline disulfonate. The irradiation of erythrocyte suspensions carried out by applying suitable aliquots of 90Sr/90Y in incubation media.
An essential decrease the ferricyanide reductase activity (12-25%) of human erythrocytes under the radiation field with a dose rate of 100.0 µGy×h-1was observed. Phenilephrine, a selective a1-adrenoreceptor agonist, in PBS did not influence on basal activity of the ferricyanide reductase activity, and did not change substantially the effect of the ionizing field at all dose rates investigated (1.0-100 μGy∙h-1). However, phenilephrine in Krebs-Henseleit bicarbonate buffer decreased the ferricyanide reductase activity relative to control whereas the radiation field (10 µGy∙h-1) did not influence on this activity. On the contrary, naftopidil, selective α1-adrenergic receptor antagonist, in Krebs-Henseleit bicarbonate buffer increased the ferricyanide reductase activity relative to control (to24%), and the radiation field strengthened its effect up to 58%.
The findings indicate that the low dose rate ionizing field modifies cellular signaling regulating the reductase activity of erythrocyte membrane. A direction of that modification presumably depends on the initial structure of membranes, and it is determined by the quality and quantitative parameters of changes in membrane structure caused by concrete operable factors. These findings denote the necessity for monitoring of absorbed doses of ionizing radiation at the use of radionuclides in biochemical investigations of membrane bound enzymes, and signal system components.