This preclinical study demonstrates that the majority of intracellular water in cat ventricular muscle is osmotically active, though univalent cations may remain bound at extreme hyperosmolality.
Preclinical osmotic data in feline myocardium leave open whether most intracellular water is freely mobile in human cardiac cells under physiologic stress.
Cell contents of water, K, Na, and Cl have been determined in cat right ventricular papillary muscles immersed in solutions with and without NaCl when the external osmolality was varied with sucrose. The plot of cell water/kilogram dry weight (corrected for sucrose content) vs. (external osmolality)(-1) suggests that not less than 82% of water present in cells at physiological external osmolality is free to move across the cell membrane in response to an imposed osmotic gradient. Cells fail to increase their water content in very hypotonic solutions. For osmolalities greater than 5 times isosmolal, at which the mannitol space and the Cl(36) space are both equal to 100% of muscle water, rather large amounts of univalent cation appear to remain "bound" to the tissue.
No takes yet. Share an insight, caveat, or question.
Page et al. (1966) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: