Water and ions in muscles and model systems.

THE NUCLEAR MAGNETIC REASONANCE (NMR) RELAXATION TIMES OF PROTONS IN TOAD MUSCLE WATER HAVE BEEN MEASURED AT THREE FREQUENCIES: 2.3, 8.9, and 30 MHz. The results are analyzed in terms of a distribution of correlation times, and it is found that only a few percent of the observed protons have mobilities more than two orders of magnitude smaller than normal. Sodium and chloride ion chemical potentials in some hydrated materials with similar proton NMR characteristics to toad muscle have been found to be heightened, but not sufficiently to account for the distribution of sodium ions in muscle.