Decrease in stiffness during shortening in calcium activated skinned muscle fibers.

T Tsuchiya; K Güth; H J Kuhn; J C Rüegg

doi:10.1007/bf00581626

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Decrease in stiffness during shortening in calcium activated skinned muscle fibers.

T Tsuchiya·K Güth·H J Kuhn·J C Rüegg

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Abstract

Single fibers from frog sartorius or semitendinosus muscle were mechanically skinned and activated in ATP salt solution containing 10 micro M Ca2+ (7 degrees C). After development of an isometric contraction, fibers were released at constant speed (0.03-2.4 s-1). During ramp shortening, stiffness was determined from the slope of the tension-length diagram obtained during superimposed quick stretches. Both force and stiffness decreased, as the ramp shortening proceeded and approached a steady value after about 60 ms. An increase in speed of shortening caused a decrease in fiber tension and stiffness and an increase in the ratio of stiffness to tension, suggesting a decrease in both the number of attached crossbridges and in the average force per crossbridge.

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Animals Calcium Elasticity Homeostasis Muscle Contraction Rana catesbeiana Rana temporaria Time Factors Journal Article Research Support, Non-U.S. Gov't

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T Tsuchiya, K Güth, H J Kuhn, J C Rüegg. 1982. Decrease in stiffness during shortening in calcium activated skinned muscle fibers.. https://doi.org/10.1007/bf00581626

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