Perelman School of Medicine at the University of Pennsylvania

Professor of Physiology

Department of Physiology
A406 Richards Building
3700 Hamilton Walk
Philadelphia, PA 19104-6085

Phone: (215) 898-5559
Fax: (215) 573-5851

Other Perelman School of Medicine Affiliations
Mahoney Institute of Neurological Sciences
Cell and Molecular Biology Graduate Group
Neurosciences Graduate Group
Pennsylvania Muscle Institute

B.A., Knox College, 1965
M.A., University of Illinois, 1966
M.D., Stanford University, 1971

Established Investigator of the American Heart Association (1978-83)
Jacob Javits Neuroscience Investigator Award (1989-1996)
Dean's Award for Excellence in Teaching of the Basic Sciences, 1990.

Professional Affiliations
Biophysical Society
Society of General Physiologists

Research Description
This cell physiology laboratory studies excitation-contraction (E-C) coupling in vertebrate skeletal muscle and the role of the calcium ion (Ca) as an intracellular chemical messenger. The methodology relies on optical, electrical and mechanical measurements from living single muscle fibers. Current work tests hypotheses about calcium and E-C coupling in fast twitch fibers of frog muscle, with some work also carried out on fiber types of other species (e.g., fast-twitch fibers of mouse, super-fast fibers of toadfish and rattlesnake, slow twitch fibers of mouse and toadfish).

Specific areas of active investigation include: (a) use of laser-scanning confocal microscopy to study myoplasmic calcium "sparks", which are brief localized increases in fluorescence measurable with a Ca-indicator such as fluo-3 and thought to reflect the opening of one or a few Ca release channels of the sarcoplasmic reticulum (=ryanodine receptors, RyRs); (b) estimation of local Ca movements within the sarcomere by means of computer modeling; (c) the role that myoplasmic Ca levels play in activation and inactivation gating of RyRs; (d) the possibility that either activation or inactivation of RyRs may vary with the RyR isoform composition (RyR1, RyR3, etc.).


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(searches the National Library of Medicine's PubMed database.)

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