Basic Fibroblast Growth Factor–Induced Endothelial Proliferation and NO Synthesis Involves Inward Rectifier

Objectives—Inward rectifier K currents (Kir) determine the resting membrane potential and thereby modulate essential Ca -dependent pathways, like cell growth and synthesis of vasoactive agents in endothelial cells. Basic fibroblast growth factor (bFGF) acts as a vasodilatator and angiogenic factor. Therefore, we investigated the effect of bFGF on Kir and assessed the role in proliferation and nitric oxide (NO) formation of endothelial cells. Methods and Results—Using the patch-clamp technique, we found characteristic Kir in human umbilical cord vein endothelial cells (HUVEC), which were dose-dependently blocked by barium (10 to 100 mol/L). Perfusion with bFGF (50 ng/mL) caused a significant increase of Kir, which was blocked by 100 mol/L barium (n 18, P 0.01). The bFGF-induced HUVEC proliferation was significantly inhibited when using 50 to 100 mol/L barium (n 6; P 0.01). NO production was examined using a cGMP radioimmunoassay. bFGF caused a significant increase of cGMP levels (n 10; P 0.05), which were blocked by barium. Conclusions—Modulation of Kir plays an important role in bFGF-mediated endothelial cell growth and NO formation. (Arterioscler Thromb Vasc Biol. 2004;24:1229-1233.)