Electric fields can have profound effects on biological systems, influencing processes such as differentiation, directed cell and neurite motility, and wound healing. Although it is widely appreciated that the fields can produce small asymmetrically distributed changes in membrane potential, it is not understood how these are amplified and translated into biochemical and biological responses at the level of the cell. This application proposes to test the hypothesis that the field induces a redistributed molecules and Ca2+ channels, clustered this way, produce foci of increased calcium activity which mediate cellular responses. To test these hypotheses, 2 cell types will be used. N1E-115 neuroblastoma cells have calcium channels which are heterogeneously distributed and appear to be involved in neurite outgrowth; they will be used as a model for galvanotropism. The relationship of the dynamics of cell surface molecules and calcium levels to the movement of fish keratocytes has been studied; they also exhibit directed motility in electric fields. Field effects on individual cells will be examined with digital imaging microscopy to study: membrane potential distribution (using potentiometric dyes), calcium channel distribution (using fluorescence and autoradiography with specific antibody or toxin probes), local changes in intracellular calcium levels (using FURA-2), cell and cell-surface particle tracking (using differential interference contrast), and actin cycling (using fluorescent actin and fluorescence recovery after photobleaching techniques).

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
1R01ES005973-01
Application #
3254295
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1992-02-01
Project End
1995-01-31
Budget Start
1992-02-01
Budget End
1993-01-31
Support Year
1
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Connecticut
Department
Type
Schools of Dentistry
DUNS #
City
Farmington
State
CT
Country
United States
Zip Code
06030
Brown, M J; Loew, L M (1996) Graded fibronectin receptor aggregation in migrating cells. Cell Motil Cytoskeleton 34:185-93
Zhang, J; Loew, L M; Davidson, R M (1996) Faster voltage-dependent activation of Na+ channels in growth cones versus somata of neuroblastoma N1E-115 cells. Biophys J 71:2501-8
Koppel, D E; Morgan, F; Cowan, A E et al. (1994) Scanning concentration correlation spectroscopy using the confocal laser microscope. Biophys J 66:502-7
Bedlack Jr, R S; Wei, M D; Fox, S H et al. (1994) Distinct electric potentials in soma and neurite membranes. Neuron 13:1187-93
Brown, M J; Loew, L M (1994) Electric field-directed fibroblast locomotion involves cell surface molecular reorganization and is calcium independent. J Cell Biol 127:117-28
Gross, E; Bedlack Jr, R S; Loew, L M (1994) Dual-wavelength ratiometric fluorescence measurement of the membrane dipole potential. Biophys J 67:208-16
Bedlack Jr, R S; Wei, M; Loew, L M (1992) Localized membrane depolarizations and localized calcium influx during electric field-guided neurite growth. Neuron 9:393-403