Role of viscosity and permeability of erythrocyte plasmatic membrane in controlling the oxygen transport effectiveness by human hemoglobin on completion of space flight
Plasmatic membrane viscosity and permeability and hemoporphyrine conformation in human hemoglobin were studied on completion of long-duration space flight (LSF). Reversible increases in viscosity and selective per-meability (Na+/H+-turnover) of erythrocyte plasmatic membrane were observed immediately after and in the period of recovery from LSF. Viscosity of lipids in both externa/ and internal loca-tions of plasmatic membrane in human erythrocytes was changed after LSF. The reversible rise of the Na+/H+-turnover is likely to alter intracellular pH and oxygen binding with hemoglobin. The former is con-firmed by the concurrent reversible decline in the de-oxyhemoglobin ability to bind oxygen and the oxyhe-moglobin ability to retain oxygen. In LSF and during readaptation to the normal gravity blood levels of he-moglobin and free iron are known to be reduced and may be answerable for the hypoxic state of human organism.