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Stephen
M. Baylor, M.D.
Professor, Dept of Physiology
Cell
Biology and Physiology Program
Address
A406 Richards Building (Lab)
3700 Hamilton Walk
Philadelphia, PA 19104-6085
Office tel.: 215 898-5559
Lab tel.: 215 898-5219
Fax: 215 573-5851
E-mail: baylor@mail.med.upenn.edu
Link(s)
Neuroscience
Graduate Group
Education
Knox College: BA (Mathematics), 1965.
University of Illinois: MA (Mathematics), 1966.
Stanford University: MD, 1971.
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Research Interests
- excitation-contraction coupling; intracellular calcium
signaling.
Key
words: excitation-contraction coupling;
ryanodine receptors; calcium sparks; skeletal muscle.
Description of Research
Dr. Baylor's research is focused on excitation-contraction
(E-C) coupling in vertebrate skeletal muscle and the role
of the calcium ion (Ca) as an intracellular messenger. The
methodology relies primarily on indicator dye measurements
of myoplasmic free [Ca], both in resting muscle fibers and
in fibers stimulated electrically. Much of the recent work
has involved testing hypotheses about calcium and E-C coupling
in fast twitch fibers of frog muscle, with some work also
carried out on twitch fibers in other species (e.g., fast-twitch
and slow-twitch fibers of mouse, super-fast fibers of toadfish
and rattlesnake).
Areas of active investigation include: use of laser-scanning
confocal microscopy to measure "calcium sparks",
which are brief localized increases in fluorescence from a
Ca-indicator such as fluo-3 that are thought to be reflective
of the transient opening of one or a few RyRs (=ryanodine
receptors), the Ca release channels of the sarcoplasmic reticulum
(SR); the possibility that the mechanism of activation of
RyRs involves both voltage-gating and Ca-gating; the nature
of the mechanism whereby SR Ca release is inactivated by a
rise in myoplasmic free [Ca]; the possibility that either
activation or inactivation of SR Ca release may vary with
the RyR isoform composition (RyR1, RyR3, etc.); estimation
of local Ca movements within the sarcomere by means of computer
modeling, including estimation of the kinetics of binding
of Ca to the intracellular Ca buffers troponin, parvalbumin,
ATP, and the SR Ca pump.
Selected
Publications
Baylor, S. M. and Hollingworth, S. 2007. Simulation of Ca2 + movements within the sarcomere of fast-twitch mouse fibbers stimulated by action-potentials. J. Gen.
Physiol. 130:283-302.
Hollingworth, S., W. K. Chandler and
S. M. Baylor. 2006. Effects of tetracaine on calcium
sparks in frog intact skeletal muscle fibers. J. Gen.
Physiol. 127:291-307.
Baylor, S.M. Calcium sparks
in skeletal muscle fibers. Cell Calcium. 37:513-530,
2005.
Baylor, S. M., Hollingworth,
S. Sarcoplasmic reticulum calcium release compared in slow-twitch
and fast-twitch fibres of mouse muscle. J. Physiol.
551:125-138, 2003.
Baylor, S. M., Hollingworth,
S., Chandler, W. K. Comparison of modeled and measured calcium
sparks in intact skeletal muscle fibers of the frog. J.
Gen. Physiol. 120:349-368, 2002
Search PubMed for more articles
Lab
Rotation Projects
- Analysis of myoplasmic calcium movements during activity
of vertebrate skeletal muscle fibers
- Search for calcium sparks in mammalian twitch muscle fibers
- Lab
personnel:
Stephen Hollingworth, PhD - Senior Research Investigator
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last updated 7/2008
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