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Calcium Release and Spread Within the Sarcomere of Vertebrate Skeletal Muscle Fibers.

Published online by Cambridge University Press:  02 July 2020

Stephen M. Baylor  and
Stephen Hollingworth
Stephen M. Baylor
Affiliation:
Department of Physiology, University of Pennsylvania, Philadelphia, PA19104-6085.
Stephen Hollingworth
Affiliation:
Department of Physiology, University of Pennsylvania, Philadelphia, PA19104-6085.
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Extract

Experiments were carried out to investigate excitation-contraction coupling in vertebrate skeletal muscle fibers. Single-dissected twitch fibers of frog muscle were injected with flourescent calcium (Ca) indicators, and fluorescence intensity (F) and changes in intensity (ΔF) were recorded during various stimulation protocols (16-22 °C). In fibers activated by an action potential, the low-affinity indicator furaptra was used to estimate the spatially-averaged change in myoplasmic free calcium concentration (ΔC[a]; peak value, 15-20 μM; time to peak, 4-5 ms). Δ[Ca], in combination with a kinetic model, was used to calculate the change in concentration of calcium bound to the principal myoplasmic Ca buffers (ATP, troponin, parvalbumin). The rate of Ca release from the sarcoplasmic reticulum (SR) was obtained from the time derivative of the estimated change in total myoplasmic calcium concentration, Δ[CaT] (= Δ[Ca] + Δ[CaATP] + Δ[CaTroponin] + Δ[CaParvalbumin]).

Type
Philadelphia—The Other Motor City: Muscle and Non-Muscle Motility. A Dedication to Dr. Lee Peachey
Information
Microscopy and Microanalysis , Volume 6 , Issue S2: Proceedings: Microscopy & Microanalysis 2000, Microscopy Society of America 58th Annual Meeting, Microbeam Analysis Society 34th Annual Meeting, Microscopical Society of Canada/Societe de Microscopie de Canada 27th Annual Meeting, Philadelphia, Pennsylvania August 13-17, 2000 , August 2000 , pp. 94 - 95
Copyright
Copyright © Microscopy Society of America

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References

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