Glycerinated Skeletal and Smooth Muscle: Calcium and Magnesium Dependence

See allHide authors and affiliations

Science  26 Mar 1965:
Vol. 147, Issue 3665, pp. 1581-1583
DOI: 10.1126/science.147.3665.1581


Contractions of glycerinated skeletal (striated) and vascular (smooth) muscles are similar in their calcium dependence but differ in their magnesium dependence. The threshold concentration of free Ca++ for contraction of either muscle was 1.8 x 10-7M; maximum tension developed when the concentration of free Ca++ was slightly greater than 10-6M. The Mg concentration required for contraction of smooth muscle was at least ten times as great as that for skeletal muscle.