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.
Characterization of voltage-dependent calcium influx in human erythrocytes by fura-2 / L. Soldati, R. Spaventa, G. Vezzoli, S. Zerbi, D. Adamo, A. Caumo, R. Rivera, G. Bianchi. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 236:3(1997 Jul 30), pp. 549-554. [10.1006/bbrc.1997.7002]
Characterization of voltage-dependent calcium influx in human erythrocytes by fura-2
L. SoldatiPrimo
;G. Vezzoli;D. Adamo;A. Caumo;
1997
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.Pubblicazioni consigliate
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