17O Nuclear Magnetic Resonance Spectrum of H217O in Frog Striated Muscle

Whole striated muscles from the frog Rana esculenta were bathed in Ringer's solution enriched with H₂¹⁷O; the muscle water was subsequently collected by vacuum distillation. The integrated intensity of the nuclear magnetic resonance (NMR) signal of ¹⁷O in the muscle was measured to be approximately ¾ of the signal observed in the distilled water. The phenomenon may arise either from immobilization of a population of the water molecules which may be a very small fraction or as much as ¼ of the total, or may reflect tumbling of ⅓ of the water molecules in a compartment containing an anisotropic medium. Such an effect was demonstrated for H₂¹⁷O using the model system of sodium linoleate in water.