Calcium transients in intact rat skeletal muscle fibers in agarose gel.
Carroll, Stefanie L., Michael G. Klein, and Martin F. Schneider.
Department of Biological Chemistry, University of Maryland, School of
Medicine, Baltimore Maryland 21201
APStracts 2:0068C, 1995.
Intact single fibers enzymatically dissociated from rat flexor digitorium
brevis muscle were suspended in .5% low melting temperature agarose gel to
minimize fiber movement during action potentials or trains of action
potentials. Resting [Ca2+] and changes in [Ca2+] were monitored
using the fluorescence indicator fura-2. The time course and waveform of
[Ca2+] transients during an action potential or trains of action
potentials in fibers in agarose were calculated using kinetic parameters
previously determined to correct for the calcium fura-2 kinetic delay. Half
-times of the calculated calcium transients for single action potentials were
30-fold briefer than the original fura-2 signals. To confirm the time course
and waveform of the calculated calcium transients, changes in [Ca2+]
were monitored using the more rapidly equilibrating calcium indicator mag
-fura-2. [Ca2+] transients for fibers containing fura-2 had very similar
time courses and waveforms as mag-fura-2 signals from other fibers,
indicating that the corrections for the calcium fura-2 kinetic delay were
accurate. The advantages of the agarose gel suspension are discussed.
Received 17 May 1994; accepted in final form 3 January 1995.
APS Manuscript Number C268-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 February 1995.