ZM323881 inhibits VEGF-A, EGF and bFEF induced HUVEC cell proliferation with IC50 of 8 nM, 1.9 μM and 1.6 μM, respectively. ZM323881 (10 nM) abolishes VEGF-A-mediated increases in vascular permeability in perfused mesenteric microvessels in male leopard. ZM323881 (10 nM) blocks the increase in intensity of the VEGF-R2 band in the lung of male leopard frogs. M323881 (1 μM) blocks activation of extracellular regulated-kinase, p38, Akt, and endothelial nitric oxide synthetase (eNOS) by VEGF, but did not inhibit p38 activation by the VEGFR-1-specific ligand, placental growth factor (PIGF) in human aortic endothelial cells (HAECs). ZM323881 (1 μM) also perturbes VEGF-induced membrane extension, cell migration, and tube formation by HAECs. ZM323881 (1 μM) reverses VEGF-stimulated phosphorylation of CrkII and its Src homology 2 (SH2)-binding protein p130Cas, which are known to play a pivotal role in regulating endothelial cell migration. ZM323881 (10 nM) completely blocks VEGF-induced VEGF promoter activity in SCC-9 cells. ZM323881 (10 nM) blocks VEGF stimulated Hif-1α protein accumulation in SCC-9 cells. ZM323881 (10 nM) blocks VEGF-induced Rac1 activation at 30 min in HUVECs. ZM323881 (10 nM) prevents Vav2 tyrosine phosphorylation in response to VEGF in HUVECs.