Ionic Mobility in Muscle Cells

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Science  05 Dec 1969:
Vol. 166, Issue 3910, pp. 1297-1298
DOI: 10.1126/science.166.3910.1297


The diffusivities of ionic potassium, sodium, sulfate, and adenosine triphosphate inside a nmuscle cell are reduced by a factor of 2, relative to diffusivities in aqueous solution. The diffusion coefficients of nonelectrolytes are reduced by the same factor, showing that the diffusion of the ions is retarded by physical, rather than chemical, interactions. In contrast, the diffusivity of the calcium ion, which is taken up by the sarcoplasmic reticulum, is reduced fiftyfold.

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