title: Spin-echo nuclear magnetic resonance evidence for complexing of sodium ions in muscle, brain, and kidney.
abstract: Na(+) in muscle, brain, and kidney is shown by spin-echo nuclear magnetic resonance (NMR) to consist of two fractions with different NMR parameters. The slow fraction of Na(+) in these tissues has NMR relaxation times T(1) and T(2) of 10-15 x 10(-3) sec, which is approximately 4-5 times shorter than for Na(+) in aqueous NaCl solution. The slow fraction may represent Na(+) dissolved in structured tissue water. The fast fraction of tissue Na(+), which is shown to represent approximately 65% of the total tissue Na(+) concentration, has T(2) less than 1 x 10(-3) sec, which resembles the values of T(2) observed for Na(+) complexed by synthetic ion-exchange resins. One is drawn to the conclusion that approximately 65% of total Na(+) in muscle, brain, and kidney is complexed by tissue macromolecules.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D007475:Ion Exchange Resins; D007668:Kidney / Q000378:metabolism*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride; D012975:Sodium Isotopes
chemical_list: D007475:Ion Exchange Resins; D046911:Macromolecular Substances; D012975:Sodium Isotopes; D012965:Sodium Chloride; D012964:Sodium