Fatty Acid Composition of Erythrocyte Phospholipids in Rats Exposed to Stress (Prolonged Swimming)

The fatty acid composition of phospholipids was studied in rat erythrocytes after exhausting swimming. It was shown that this stressful exposure does not affect the fatty acid (FA) composition of erythrocyte phospholipids. However, differences in the variability of quantitatively dominant fatty acids were detected in stress-exposed animals compared to unstressed control. In saturated acids (C16:0, 18:0) and polyenoic arachidonic acid (C20:4ω6), the variability was close to its control values, while in unsaturated fatty acids (C18:1, C18:2ω6) it exceeded those 3–4 times. The obtained results indicate significant alterations in the unsaturated fatty acid composition of erythrocyte membrane phospholipids. Due to unsaturated fatty acids, a potential arises in the insulating layer between two surface charges of the erythrocyte plasma membrane. This additional internal potential, alongside with the potential difference between outer and inner surfaces of the erythrocyte plasma membrane, affects aqueous pores and Na+, K+-channels which jointly mediate diffusion of oxygen molecules. The revealed extraordinary variability of unsaturated fatty acids (C18:1, C18:2) with their mobile ω-electrons may relate to the mechanism of chemical interaction between phospholipid fatty acids in the hydrophobic zone of the erythrocyte plasma membrane due to phospholipid diffusion. Analogous mechanism of chemical interaction (via a proton jump from the hydronium ion to the water molecule) occurs in the hydrophilic (aqueous) zone.