Abstract
We gravimetrically observed evaporation of myowater components from skinned skeletal muscle. Fiber bundles of around 30-130 mg dissected from sartorius muscle of bullfrogs were skinned chemically with 0.5% Triton X-100. The specimen was equilibrated with the controlled humidity at room temperature. The humidity was gradually decreased from 95 to 5%RH. At 85-90%RH, about 60% of myowater was evaporated from the muscle. The second peak was found at 75%RH, where 5-10% was evaporated. Continuous gradual evaporation was followed with intermittent peaks found at 55 and 48%RH. At each of the humidity ranges of 74-55%RH and 55-48%RH, 5-10% of myowater was evaporated. There remained 15-25% of myowater at the lowest humidity of 5-15%. This result indicated that myowater is able to reserve at least up to 3kT of free energy in its state. Parallel observation of spin-spin relaxation of 1H-NMR signals from water protons (spectrometer: varian, Gemini 2000-300BB) indicated that myowater evaporates in the order of its relaxation time constant (T2). From the order of evaporation and the relative volume of water components characterized by characteristic T2 values, the component of T2 around 0.15 s corresponds with water evaporated at 85-90% RH. The component of 10−1.5<T2<10−1 s is considered to evaporate at 74-55%RH and the more rapidly relaxing component would evaporate at 55-48%RH. This assignment confirmed that myowater components resolved by spin-spin relaxation possess characteristics substantially distinct from each other. [Jpn J Physiol 54 Suppl:S120 (2004)]
