Thus far, the methods used to determine erythrocyte Ca2+ influx have not allowed the assessment of the kinetics of ion uptake. To overcome this drawback, we studied a new method, using the fluorescent Ca2+-chelator fura-2, which directly quantifies intracellular Ca2+ changes in human erythrocytes. This method has the advantage over previous techniques that it monitors continuously cellular Ca2+ levels. The Ca2+ influx is modulated by cellular membrane potential in the presence of a transmembrane Ca2+ concentration gradient and exhibits a first slow increase of the intracellular Ca2+ concentration, followed, after the reachment of a threshold value of 125 ± 13 nM Ca2+, by a faster increase until a plateau is reached. The influx rate is inhibited by dihydropyridines in the micromolar range. These findings support the hypothesis that erythrocyte Ca2+ influx is mediated by a carrier similar to the slow Ca2+ channels and is dependent on membrane depolarization.
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - Jul 30 1997|
ASJC Scopus subject areas
- Molecular Biology