Muscle Volume Changes: Relation to the Active State

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Science  14 May 1965:
Vol. 148, Issue 3672, pp. 971-972
DOI: 10.1126/science.148.3672.971


The volume of a frog sartorius muscle increases during a single twitch and subsequently decreases. The magnitude of volume change is 10-5 cm3 per gram of muscle. The time courses of change in volume and of onset of tension vary with temperature in a similar way, which implies a relation between the volume changes and the contraction mechanism. The character of the change depends upon the initial length of the muscle: the greatest decrease accompanies an isometric twitch at reference length. Treatment of the muscle with an iodide Ringer solution prolongs the active state and the volume change. These results suggest a correlation between the volume changes and the active state.