Nonselective cation channels in endothelial cells derived from human umbilical vein

M. Kamouchi, A. Mamin, G. Droogmans, B. Nilius

Research output: Contribution to journalArticle

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Abstract

(i) We have used a combined patch-clamp and fura-2 fluorescence technique to characterize a nonselective cation channel (NSC) in Ea.hy926 (EA) cells, an endothelial cell line derived from human umbilical vein. (ii) Stimulation with ATP, histamine and bradykinin activated slowly and with a long delay after application of the agonist, a nonselective cation current (I(NSC)) which is time- and voltage-independent. The permeability sequence for cations was P(Na) > P(Cs) >> P(NMDG), P(Ca). In the absence of external Ca2+ and at rather high concentrations, La3+ and Gd3+ blocked I(NSC). (iii) Single channel analysis revealed that ATP activates in the cell- attached configuration a nonselective cation channel with a conductance of approximately 24 pS and a permeation sequence identical to that of the macroscopic current. The channel activity disappeared after membrane excision. (iv) Activation of NSC required physiological intracellular Ca2+ levels (100 nM or higher). All agonists failed to activate NSC if cytosolic Ca2+ ([Ca2+](i)) was lowered by 10 mM BAPTA. Clamping internal Ca2+ at 1 μm sometimes (8 out of 17 cells) spontaneously activated I(NSC) in the absence of any additional stimulus. (v) Application of 2,5-di-tert- butylhydroquinone and internal perfusion of inositol 1,4,5-trisphosphate also activated I(NSC). The phospholipase C inhibitor, U-73122 inhibited I(NSC) and the sustained Ca2+ plateau during agonist stimulation whereas the inactive analogue, U-73343 had no effect. (vi) These results indicate NSC may act as a Ca2+ entry pathway in endothelium. [Ca2+](i) and inositol 1,4,5- trisphosphate play a role in the activation cascade of NSC, and possibly also store depletion.

Original languageEnglish
Pages (from-to)29-38
Number of pages10
JournalJournal of Membrane Biology
Volume169
Issue number1
DOIs
Publication statusPublished - May 17 1999
Externally publishedYes

Fingerprint

Human Umbilical Vein Endothelial Cells
Cations
Inositol 1,4,5-Trisphosphate
Adenosine Triphosphate
Umbilical Veins
Fura-2
Type C Phospholipases
Bradykinin
Constriction
Histamine
Endothelium
Permeability
Endothelial Cells
Perfusion
Fluorescence

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Physiology
  • Cell Biology

Cite this

Nonselective cation channels in endothelial cells derived from human umbilical vein. / Kamouchi, M.; Mamin, A.; Droogmans, G.; Nilius, B.

In: Journal of Membrane Biology, Vol. 169, No. 1, 17.05.1999, p. 29-38.

Research output: Contribution to journalArticle

Kamouchi, M. ; Mamin, A. ; Droogmans, G. ; Nilius, B. / Nonselective cation channels in endothelial cells derived from human umbilical vein. In: Journal of Membrane Biology. 1999 ; Vol. 169, No. 1. pp. 29-38.
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