Single and Multiple Quantum NMR Relaxation Times of Sodium and Potassium in Red Blood Cells

The two components T_2f and T_2s of the transverse magnetization decay curve of ²³Na in dog erythrocytes were measured using the triple quantum filtered spectra. It was shown that this technique, in spite of its inferior sensitivity, may be used for systems where T_2f and T_2s are not very different. Thus it was possible to measure the effect of 2, 3‐diphosphoglycerate (2, 3 DPG) depletion on the intracellular ²³Na relaxation rates. The effect found indicates some contribution of hemoglobin‐2, 3‐DPG complexes to the ²³Na relaxation in intact erythrocytes. ³⁹K relaxation times were measured in human and chicken erythrocytes. The results indicate binding similar to that of ²³Na. Finally, a decrease of the cellular volume of erythrocytes was found to shorten ²³Na relaxation times. The result was interpreted as due to an increase in intracellular concentration of proteins.