We have shown the increase of Src(Tyr416) phosphorylation in rat colonic mucosa at early stages of 6% iodoacetamide-induced ulcerative colitis (UC), while the level of Src protein expression was not changed. Pretreatment of rats with Src inhibitor PP1 (0.2 mg/100 g, subcutaneously) decreased the colonic vascular permeability (VP) (P < or = 0.001) and pSrc(Tyr416) level during iodoacetamide-UC. Iodoacetamide-induced autophosphorylation and upregulation of VEGFR-2 was associated with Src activation in colonic mucosa of rats. Sequentially, protein-protein interaction between beta-arrestine2 and VE-cadherine was enhanced, that might be a reason of colonic endothelium barrier disruption. We concluded that Src plays a key role in the mechanisms of increasing the colonic VP during experimental UC.