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Delta alkalinity: a simple method to measure cellular net acid-base fluxes
Z H Burbea1, S R Gullans, S Ben-Yaakov
1Renal Division, Brigham and Women's Hospital, Boston, Massachusetts.
The American Journal of Physiology
|October 1, 1987
Summary
This study introduces a new method to measure acid-base transport across cell membranes using alkalinity changes, overcoming limitations of previous techniques for accurate cell homeostasis research.
Area of Science:
- Cell Biology
- Physiology
- Biochemistry
Background:
- Cellular acid-base transport is crucial for homeostasis and growth.
- Existing flux measurement techniques have limitations regarding assumptions and solution conditions.
Purpose of the Study:
- To develop a novel, accurate method for quantifying net acid-base fluxes across cell plasma membranes.
- To overcome limitations of current techniques by using standard physiological media.
Main Methods:
- Adapted a marine chemistry approach using acid titration to determine extracellular alkalinity.
- Quantified net acid-base changes by monitoring changes in alkalinity (delta alkalinity).
- Developed a secondary titration to differentiate bicarbonate and nonbicarbonate fractions.
Main Results:
- Demonstrated that delta alkalinity accurately reflects net acid-base changes in the medium.
- Successfully measured net chloride-bicarbonate exchange in human erythrocytes with a ratio of 1.01 ± 0.03.
- Validated the method's applicability in physiological buffer concentrations without CO2 correction.
Conclusions:
- Extracellular delta alkalinity measurements provide a precise and versatile tool for studying acid-base fluxes in various cell systems.
- The new method avoids assumptions about intracellular compartments and buffer properties, enhancing physiological relevance.
- This technique offers a significant advancement for understanding cell membrane transport and homeostasis.