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CALCIUM CONTENT OF THE ERYTHROCYTES: A SENSITIVE AND EASY HANDLING METHOD FOR MEASURING FREE CALCIUM IONS, AND MODULATION OF THE Ca 2 + ION CONCENTRATION BY THE CALCIUM ANTAGONISTS NIFEDIPINE AND PENTOXIFYLLINE
Author(s) -
Friederichs E.,
Rädisch T.,
Winkler H.
Publication year - 1989
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1989.tb01576.x
Subject(s) - calcium , ionophore , digitonin , chemistry , nifedipine , ion , ion transporter , atpase , biophysics , analytical chemistry (journal) , inorganic chemistry , chromatography , biochemistry , membrane , biology , enzyme , organic chemistry
SUMMARY 1. A method for determining free Ca 2+ ‐ions in the erythrocyte is described, using a commercially available ORION‐Ca‐electrode and calomel reference electrode assembly, where changes in free Ca 2+ ‐ion concentration upon addition of 0.01% digitonin could be measured. 2. The average value found for fresh cells from 20 healthy donors at 37°C (pH = 7.4) was 0.20 ± 0.04 μmol/L referred to a haematocrit of 10%. 3. Decrease of the simultaneously determined adenosinetriphosphate (ATP) concentration indicates that ATP is presumably needed to activate the Ca‐ATPase. 4. In vitro addition of the calcium antagonists pentoxifylline and nifidepine, respectively, induced a normalization of the intraerythrocytic Ca 2+ ‐ion concentration after previous increase with the ion carrier ionophore A23187. 5. The advantages and possible clinical applications of this method are discussed.