Characterization of voltage-dependent calcium influx in human erythrocytes by fura-2

Laura Soldati, Renato Spaventa, Giuseppe Vezzoli, Simona Zerbi, Donatella Adamo, Andrea Caumo, Rodolfo Rivera, Giuseppe Bianchi

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Pages (from-to)549-554
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume236
Issue number3
DOIs
Publication statusPublished - Jul 30 1997

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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