Effect of Disuse on Sarcoplasmic Reticulum in Fast and Slow Skeletal Muscle

Authors

D. H. Kim, Marquette University
Frank Arthur Witzmann, Marquette University
Robert H. Fitts, Marquette UniversityFollow

Document Type

Article

Language

eng

Format of Original

5 p.

Publication Date

9-1982

Publisher

American Physiological Society

Source Publication

American Journal of Physiology - Cell Physiology

Source ISSN

0002-9513

Original Item ID

DOI: 10.1152/ajpcell.1982.243.3.C156

Abstract

The effect of 6 wk of hindlimb immobilization on rat skeletal muscle sarcoplasmic reticulum (SR) was determined in the slow-twitch, type I soleus (SOL), the fast-twitch, type IIA deep region of the vastus lateralis (DVL), and the fast-twitch, type IIB superficial region of the vastus lateralis (SVL). Immobilization produced a significant decline in the Ca²⁺ uptake rate (V_max) of SR vesicles from the slow SOL (0.930 ± 0.116 to 0.365 ± 0.071 µmol Ca²⁺ · mg^-1 ·min^-1), while the SR V_max increased in the fast SVL (2.763 ± 0.133 to 5.209 ± 0.687) and was unaltered in the DVL. Vesicles from the fast SVL and DVL also exhibited a higher total Ca²⁺ uptake capacity following immobilization. An evaluation of the time course of the immobilization-mediated effect revealed an increased Ca²⁺ uptake capacity in all three samples after 1 wk. In the SOL total Ca²⁺ uptake returned to control level after 2 wk, while in the fast-twitch muscles the higher capacities were maintained. The Ca²⁺-stimulated SR ATPase activity was not altered in any of the muscles studies, although the total SR ATPase activity increased twofold in the slow SOL.

Comments

American Journal of Physiology - Cell Physiology, Vol. 243, No. 3 (September 1982): C156-C160. DOI.

Recommended Citation

Kim, D. H.; Witzmann, Frank Arthur; and Fitts, Robert H., "Effect of Disuse on Sarcoplasmic Reticulum in Fast and Slow Skeletal Muscle" (1982). Biological Sciences Faculty Research and Publications. 469.
https://epublications.marquette.edu/bio_fac/469