title: Age-dependent alterations of the intracellular water and electrolyte content of heart and muscle cells.
abstract: Age-dependent alterations in intracellular concentrations of monovalent ions (Na+, K+ and Cl-) were measured in heart and muscle cells of rats using energy dispersive X-ray microanalysis of bulk specimens. Separate measurements were performed in order to get the elemental concentrations in the dry mass of the cells, and to determine the intracellular water and dry-mass content. The in vivo concentrations were calculated from these two measurements assuming that the monovalent ions were dissolved in the cell water. A statistically significant decrease was measured in the water content of the myocytes of old rats, suggesting an increase in density and viscosity of the cytoplasmic colloid during aging. This loss of cellular water was accompanied by a significant increase in both the single ion concentrations and the total monovalent ion content of the intracellular water. These age-dependent alterations in heart and muscle cells are similar to those demonstrated previously in neurons and hepatocytes.
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002470:Cell Survival; D002712:Chlorides / Q000378:metabolism*; D005260:Female; D007424:Intracellular Fluid / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*
chemical_list: D002712:Chlorides; D012964:Sodium; D011188:Potassium