[Activity of Mg2+, Ca2+-ATPase and lipid concentration in the plasma membranes rat brain synaptosomes in the early stages of acute radiation injury].

It is established that an hour after total X-ray irradiation of animals in a dose of 0.21 C/kg the Ca2+ content increases in a homogenate and subcellular fractions of the nervous tissue. The activity of Mg2+, Ca2+-ATP-ase in synaptosome plasma membranes becomes 1.6 times as high as under normal conditions. Changes are also observed in the lipid composition of synaptosome plasma membranes: an increase of the phospholipids and cholesterol contents in the composition of total lipids. The cholesterol phospholipids ratio remains about 1.0. The activation energy of ATP hydrolysis by membrane preparations isolated from the brain tissue of irradiated animals increases as compared to the normal level. It is supposed that variations in characteristics of the lipid bilayer in synaptosome plasma membranes are one of the reasons of changes in the activity of Mg2+, Ca2+-ATP-ase caused by irradiation.