New potentiometric probes are proposed based on the concepts of electrochromism, charge-transfer, and thermochromism. Synthetic schemes and methodologies for the characterization of the probes are outlined. Several new strategies are described for the design of experiments aimed at measuring potential changes in single cells and in cells in suspension. These will allow the determination of rapid changes in cell suspensions and the detection of variations in single cells that are not triggered by a controlled external stimulus; currently, neither of these situations are generally accessible to the probe methodology. In addition, the temporal and spatial distribution of membrane potential induced by an external electric field on a variety of cells will be examined with the help of the potentiometric dyes. The following specific applications of these methodologies are proposed: 1) The place of the known membrane potential change within the cascade of biochemical and biophysical events accompanying the stimulus-response in neutrophils will be defined. 2) The kinetics for insertion of a variety of membrane permeabilizing agent into lipid vesicle and cell membranes will be characterized; among the agents to be examined is cytolysin, a cytotoxic factor derived from natural killer cells. 3) The possibility of an altered potential on the membrane of cells undergoing mitosis will be explored and correlated with other variations in cell surface properties. 4) Based on changing patterns of ion permeability during spermatogenesis, we will probe for expected variations of the potential along the mature sperm membrane.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM035063-06
Application #
3287098
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1984-09-01
Project End
1989-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Connecticut
Department
Type
School of Medicine & Dentistry
DUNS #
City
Farmington
State
CT
Country
United States
Zip Code
06030
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Millard, Andrew C; Jin, Lei; Lewis, Aaron et al. (2003) Direct measurement of the voltage sensitivity of second-harmonic generation from a membrane dye in patch-clamped cells. Opt Lett 28:1221-3
Xu, Chang; Loew, Leslie M (2003) The effect of asymmetric surface potentials on the intramembrane electric field measured with voltage-sensitive dyes. Biophys J 84:2768-80
Asamoah, Osei Kwame; Wuskell, Joseph P; Loew, Leslie M et al. (2003) A fluorometric approach to local electric field measurements in a voltage-gated ion channel. Neuron 37:85-97
Xu, Chang; Watras, James; Loew, Leslie M (2003) Kinetic analysis of receptor-activated phosphoinositide turnover. J Cell Biol 161:779-91

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