Abstract

The process of excitation-contraction coupling involves a sequence of poorly understood steps leading from fiber depolarization to contractile activity. We propose to quantitatively investigate several of the intermediate steps in order either to determine the kinetic relationships between supposed successive steps or, alternatively, to establish that the events are not causally related. A new cut single muscle fiber preparation which permits modification of internal composition and provides for voltage-clamp control of membrane potential with current recording during contraction will be used. The following processes will be monitored: (1) Intra-membrane charge movements thought to be the initial voltage-sensitive step; (2) Optical signals which may be due to changes in SR membrane potential related to calcium release; (3) Myoplasmic free calcium concentration transients; (4) Fiber shortening and/or tension development.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS023346-02
Application #
3406699
Study Section
Physiology Study Section (PHY)
Project Start
1985-07-01
Project End
1986-12-31
Budget Start
1986-01-01
Budget End
1986-12-31
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost

  Institution

Name
University of Maryland Baltimore
Department
Type
Schools of Medicine
DUNS #
003255213
City
Baltimore
State
MD
Country
United States
Zip Code
21201

  Publications

Zhang, Yingfan; Rodney, George G; Schneider, Martin F (2005) Effects of azumolene on Ca2+ sparks in skeletal muscle fibers. J Pharmacol Exp Ther 314:94-102
Rodney, George G; Wilson, Gerald M; Schneider, Martin F (2005) A calmodulin binding domain of RyR increases activation of spontaneous Ca2+ sparks in frog skeletal muscle. J Biol Chem 280:11713-22
Schneider, Martin F; Rodney, George G (2004) Peptide and protein modulation of local Ca2+ release events in permeabilized skeletal muscle fibers. Biol Res 37:613-6
Rodney, George G; Schneider, Martin F (2003) Calmodulin modulates initiation but not termination of spontaneous Ca2+ sparks in frog skeletal muscle. Biophys J 85:921-32
Chun, Lois G; Ward, Christopher W; Schneider, Martin F (2003) Ca2+ sparks are initiated by Ca2+ entry in embryonic mouse skeletal muscle and decrease in frequency postnatally. Am J Physiol Cell Physiol 285:C686-97
Shtifman, Alexander; Ward, Christopher W; Yamamoto, Takeshi et al. (2002) Interdomain interactions within ryanodine receptors regulate Ca2+ spark frequency in skeletal muscle. J Gen Physiol 119:15-32
Schneider, Martin F; Ward, Christopher W (2002) Initiation and termination of calcium sparks in skeletal muscle. Front Biosci 7:d1212-22
Lacampagne, A; Klein, M G; Ward, C W et al. (2000) Two mechanisms for termination of individual Ca2+ sparks in skeletal muscle. Proc Natl Acad Sci U S A 97:7823-8
Shtifman, A; Ward, C W; Wang, J et al. (2000) Effects of imperatoxin A on local sarcoplasmic reticulum Ca(2+) release in frog skeletal muscle. Biophys J 79:814-27
Klein, M G; Lacampagne, A; Schneider, M F (1999) A repetitive mode of activation of discrete Ca2+ release events (Ca2+ sparks) in frog skeletal muscle fibres. J Physiol 515 ( Pt 2):391-411

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