In:
Journal of Vascular Research, S. Karger AG, Vol. 42, No. 5 ( 2005), p. 368-376
Abstract:
〈 i 〉 Background: 〈 /i 〉 Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells (EC) in vitro and angiogenesis in vivo. Furthermore, a role of VEGF in K 〈 sup 〉 + 〈 /sup 〉 channel, nitric oxide (NO) and Ca 〈 sup 〉 2+ 〈 /sup 〉 signaling was reported. We examined whether the K 〈 sup 〉 + 〈 /sup 〉 channel blocker margatoxin (MTX) influences VEGF-induced signaling in human EC. 〈 i 〉 Methods: 〈 /i 〉 Fluorescence imaging was used to analyze changes in the membrane potential (DiBAC), intracellular Ca 〈 sup 〉 2+ 〈 /sup 〉 (FURA-2) and NO (DAF) levels in cultured human EC derived from human umbilical vein EC (HUVEC). Proliferation of HUVEC was examined by cell counts (CC) and [ 〈 sup 〉 3 〈 /sup 〉 H]-thymidine incorporation (TI). 〈 i 〉 Results: 〈 /i 〉 VEGF (5–50 ng/ml) caused a dose-dependent hyperpolarization of EC, with a maximum at 30 ng/ml (n = 30, p 〈 0.05). This effect was completely blocked by MTX (5 µmol/l). VEGF caused an increase in transmembrane Ca 〈 sup 〉 2+ 〈 /sup 〉 influx (n = 30, p 〈 0.05) that was sensitive to MTX and the blocker of transmembrane Ca 〈 sup 〉 2+ 〈 /sup 〉 entry 2-aminoethoxydiphenyl borate (APB, 100 µmol/l). VEGF-induced NO production was significantly reduced by MTX, APB and a reduction in extracellular Ca 〈 sup 〉 2+ 〈 /sup 〉 (n = 30, p 〈 0.05). HUVEC proliferation, examined by CC and TI, was significantly increased by VEGF and inhibited by MTX (CC: –58%, TI –121%); APB (CC –99%, TI –187%); N-monomethyl- 〈 i 〉 L 〈 /i 〉 -arginine (300 µmol/l: CC: –86%, TI –164%). 〈 i 〉 Conclusions: 〈 /i 〉 VEGF caused an MTX-sensitive hyperpolarization which results in an increased transmembrane Ca 〈 sup 〉 2+ 〈 /sup 〉 entry that is responsible for the effects on endothelial proliferation and NO production.
Type of Medium:
Online Resource
ISSN:
1018-1172
,
1423-0135
Language:
English
Publisher:
S. Karger AG
Publication Date:
2005
detail.hit.zdb_id:
1482726-8
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