Membrane potential as a modulator of the free intracellular Ca2+ concentration in agonist-activated endothelial cells

M. Kamouchi, G. Droogmans, B. Nilius

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

We have used combined patch clamp and fura-2 fluorescence to elucidate the role of membrane potential in the regulation of the cytosolic Ca2+ concentration ([Ca2+]i) in a human umbilical vein derived endothelial cell-line, EA.hy926 (EA cells) stimulated with vasoactive agonists, such as ATP, histamine and bradykinin. This stimulation caused hyperpolarization and sustained Ca2+ plateau in nonclamped cells. Clamping agonist-stimulated cells at negative potentials enhanced the amplitude of this plateau, whereas it was smaller at more depolarized potentials, indicating that Ca2+ influx follows its driving force. Depolarization of the membrane by increasing extracellular K+ or by applying charybdotoxin, a blocker of big conductance Ca2+-dependent K+ channels during agonist stimulation diminished the plateau rise in [Ca2+]i . It is concluded that the membrane potential is an efficient regulator of Ca2+ influx during the plateau phase of agonist-mediated Ca2+ signals. In addition, the modulating effects on Ca2+ signals should be interpreted with caution if the membrane potential of the cells is not controlled.

Original languageEnglish
Pages (from-to)199-208
Number of pages10
JournalGeneral Physiology and Biophysics
Volume18
Issue number2
Publication statusPublished - Dec 1 1999
Externally publishedYes

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Membrane Potentials
Endothelial Cells
Charybdotoxin
Fura-2
Human Umbilical Vein Endothelial Cells
Bradykinin
Vasoconstrictor Agents
Constriction
Histamine
Adenosine Triphosphate
Fluorescence
Cell Line
Membranes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Physiology

Cite this

Membrane potential as a modulator of the free intracellular Ca2+ concentration in agonist-activated endothelial cells. / Kamouchi, M.; Droogmans, G.; Nilius, B.

In: General Physiology and Biophysics, Vol. 18, No. 2, 01.12.1999, p. 199-208.

Research output: Contribution to journalArticle

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