The effect of low doses of gamma irradiation on the homeostasis of intracellular calcium in lymphocyte cells of rats.

The influence of acute and chronic gamma irradiation (0.25 and 0.5 Gy doses) on rat lymphocytes was examined on the 1st and 10th days after irradiation. Acute gamma irradiation increased the intracellular calcium concentration in the cytoplasm of the lymphocytes on the 1st day after the influence of the radiation. Calcium concentration returned to the control level on the 10th day after the effect of the radiation at all the doses. In the lymphocytes after acute irradiation the increase of the Ca2+ concentration in the intracellular depots on the 1st day was observed. Changes were also observed in the physicochemical state of the plasma membrane of these cells. Research on the influence of prolonged gamma irradiation on intracellular calcium homeostasis revealed opposite effects in comparison with acute gamma irradiation.

[The effect of small doses of ionizing radiation on the physico-chemical characteristics of the membranes of peripheral blood lymphocytes of rats]. / Vliianie ioniziruiushchego izlucheniia v malykh dozakh na fiziko-khimicheskie kharakteristiki membran limfotsitov periferecheskoi krovi.

The fluorescence probe method was used for investigating the physical state of a total lipid phase of a bi-layer and an annular (near-protein) zone of the membrane lipids of lymphocytes in a peripheral blood of rats on the 10th day after a whole-body acute and chronic gamma-exposure to doses of 0.25, 0.5, and 1.0 Gy. It was discovered that exposure to doses of 0.25, 0.5, and 1.0 Gy revealed no reliable distinctions in the parameters of a physical state of the lipid component of membranes within the given period of observation if compared with those of controls. However chronic exposure to the same doses caused the increase in hydrophobicity of the total lipid phase of the membrane bi-layer with no change in the polarity of an annular lipid. The near-protein zone of lipids revealed a local decrease in microviscosity while the fluidity of total lipids of a membrane bi-layer remained unaltered. A detected change of tryptophan fluorescence of the membrane proteins after exposing them to small dosed has also been carried out.