Related Experiment Videos
Ratiometry of transmembrane voltage-sensitive fluorescent dye emission in hearts.
S B Knisley1, R K Justice, W Kong
1Department of Biomedical Engineering of the School of Engineering, The University of Alabama at Birmingham, Alabama 35294-0019, USA. sbk@crml.uab.edu
American Journal of Physiology. Heart and Circulatory Physiology
|September 20, 2000
Summary
Emission ratiometry using voltage-sensitive dyes significantly reduces baseline drift and motion artifacts in transmembrane voltage measurements. This technique enhances the accuracy of assessing action potentials and resting membrane potential changes in cardiac tissue.
Area of Science:
- Physiology
- Biophysics
- Optical Imaging
Background:
- Transmembrane voltage-sensitive fluorescence measurements are prone to baseline drift and motion artifacts.
- These artifacts obscure critical physiological events like resting membrane potential changes and repolarization.
Purpose of the Study:
- To evaluate the efficacy of emission ratiometry in mitigating drift and motion artifacts.
- To assess the utility of ratiometry for measuring action potentials and resting membrane potential in cardiac tissue.
Main Methods:
- Utilized di-4-ANEPPS dye in rabbit hearts with laser excitation.
- Employed a two-photomultiplier tube system and spectrofluorometer for green and red emission detection.
- Analyzed emission ratios to quantify changes in membrane potential and assess artifact reduction.
Main Results:
- Ratiometry significantly reduced drift (56-66%) and motion artifacts (123-188% increase in depolarization deflections).
- Emission ratios accurately reflected action potential contours with larger fractional changes than individual emissions.
- Ratiometry successfully indicated decreases in resting membrane potential.
Conclusions:
- Emission ratiometry effectively minimizes motion and drift artifacts in voltage-sensitive fluorescence measurements.
- This technique provides a robust method for assessing changes in resting membrane potential and repolarization.
- Ratiometry offers improved signal-to-noise ratio and accuracy for optical recordings of cardiac electrical activity.