An apparatus is described which collects the effluent from the center 0.7 cm of a single muscle fiber or bundle of muscle fibers. It was used to study the efflux of 45Ca from twitch muscle fibers. The efflux can be described by three time constants 18 ± 2 min, 300 ± 40 min, and 882 ± 172 min. These kinetics have been interpreted as those of a three-compartment system. The fastest is thought to be on the surface membrane of the muscle and of the T system. It contains 0.07 ± 0.03 mM Ca/liter of fiber and the Ca efflux is 0.11 ± 0.04 pM Ca/cm2. sec. The intermediate rate compartment is thought to represent the Ca in the longitudinal reticulum. It contains approximately 0.77 mM Ca/liter. Only the efflux from this compartment increases during stimulation. The most slowly exchanging compartment is poorly defined. Neither Ca-free nor Ni-Ringer solutions alter the rate of loss from the fastest exchanging compartment. Ni apparently alters the rate of loss from the slowest compartment.
Article|
February 01 1970
Calcium Efflux from Frog Twitch Muscle Fibers
B. A. Curtis
B. A. Curtis
From the Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111
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B. A. Curtis
From the Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111
Received:
June 02 1969
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright © 1970 by The Rockefeller University Press
1970
J Gen Physiol (1970) 55 (2): 243–253.
Article history
Received:
June 02 1969
Citation
B. A. Curtis; Calcium Efflux from Frog Twitch Muscle Fibers . J Gen Physiol 1 February 1970; 55 (2): 243–253. doi: https://doi.org/10.1085/jgp.55.2.243
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