Abstract

The research project proposed is aimed at the description, characterization and correlation of events involved in excitation-contraction coupling in twitch muscle fibers. Experiments are proposed for studying events occurring in tubular system membranes, triad and sacroplamsic reticulum membranes in addition to calcium concentration changes in thh sarcoplasm. The membrane potential changes of the tubular system and the sarcoplasmic reticulum will be monitored by voltage-sensing-dyes (fluorescence and absorption). Triadic function will be studied in correlation to charge movements. Calcium concentration changes will be monitored by calcium-sensing-dyes. Modifiers of excitation-contraction coupling will be tested to assess the role of each of the above processes in the physiology of muscle contractions. We will use a cut fiber preparation and double vaseline gap voltage clamp technique allowing modification of the internal medium of the muscle fiber, control of the surface membrane potential and measurement of optical signals. Our experiments are expected to provide new information on 1) the steps involved in excitation-contraction coupling, and 2) the links between consecutive steps. These studies are expected to be of importance in the physiology of striated muscle, including heart muscle.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR025201-07
Application #
3155281
Study Section
Physiology Study Section (PHY)
Project Start
1978-12-01
Project End
1987-11-30
Budget Start
1985-12-01
Budget End
1986-11-30
Support Year
7
Fiscal Year
1986
Total Cost
Indirect Cost

  Institution

Name
University of California Los Angeles
Department
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095

  Publications

Gomez, Jose; Neco, Patricia; DiFranco, Marino et al. (2006) Calcium release domains in mammalian skeletal muscle studied with two-photon imaging and spot detection techniques. J Gen Physiol 127:623-37
DiFranco, Marino; Neco, Patricia; Capote, Joana et al. (2006) Quantitative evaluation of mammalian skeletal muscle as a heterologous protein expression system. Protein Expr Purif 47:281-8
Woods, Christopher E; Novo, David; DiFranco, Marino et al. (2005) Propagation in the transverse tubular system and voltage dependence of calcium release in normal and mdx mouse muscle fibres. J Physiol 568:867-80
Woods, Christopher E; Novo, David; DiFranco, Marino et al. (2004) The action potential-evoked sarcoplasmic reticulum calcium release is impaired in mdx mouse muscle fibres. J Physiol 557:59-75
Novo, David; DiFranco, Marino; Vergara, Julio L (2003) Comparison between the predictions of diffusion-reaction models and localized Ca2+ transients in amphibian skeletal muscle fibers. Biophys J 85:1080-97
DiFranco, Marino; Novo, David; Vergara, Julio L (2002) Characterization of the calcium release domains during excitation-contraction coupling in skeletal muscle fibres. Pflugers Arch 443:508-19
DiGregorio, D A; Negrete, O; Jeromin, A et al. (2001) Contact-dependent aggregation of functional Ca2+ channels, synaptic vesicles and postsynaptic receptors in active zones of a neuromuscular junction. Eur J Neurosci 14:533-46
Pattillo, J M; Yazejian, B; DiGregorio, D A et al. (2001) Contribution of presynaptic calcium-activated potassium currents to transmitter release regulation in cultured Xenopus nerve-muscle synapses. Neuroscience 102:229-40
Nagerl, U V; Novo, D; Mody, I et al. (2000) Binding kinetics of calbindin-D(28k) determined by flash photolysis of caged Ca(2+) Biophys J 79:3009-18
Cifuentes, F; Vergara, J; Hidalgo, C (2000) Sodium/calcium exchange in amphibian skeletal muscle fibers and isolated transverse tubules. Am J Physiol Cell Physiol 279:C89-97

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